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Gao R, Fang Q, Zhang X, Xu Q, Ye H, Guo W, He J, Chen Y, Wang R, Wu Z, Yu J. R5 HIV-1 gp120 Activates p38 MAPK to Induce Rat Cardiomyocyte Injury by the CCR5 Coreceptor. Pathobiology 2019; 86:274-284. [PMID: 31574524 DOI: 10.1159/000502238] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 07/18/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Effective antiretroviral therapy extends the survival of patients with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome, but these patients remain at higher risk for heart diseases compared with the general population. Previous studies have suggested that HIV-1 glycoprotein 120 (gp120) may be associated with heart disease. However, the underlying mechanisms by which HIV-1 gp120-mediated myocardial injury occurs remain unknown. OBJECTIVE The current study aimed to uncover the mechanism of C-C chemokine receptor 5 (CCR5) coreceptor (R5) HIV-1 gp120-induced myocardial injury. METHODS Morphology analysis, determination of the percentage of cell apoptosis, as well as lactate dehydrogenase (LDH) and creatine kinase (CK) assays were used to analyze whether R5 HIV-1 gp120 induced myocardial cell injury. We analyzed the phosphorylation of p38 mitogen-activated protein kinase (MAPK) with the CCR5 antagonist D-Ala-peptide T-amide (DAPTA) and NMDA receptor antagonist MK801, detected LDH and CK assays with p38 MAPK antagonist SB203580 (SB), and detected the percentage of cell apoptosis and death with DAPTA to investigate the mechanism of R5 HIV-1 gp120-induced myocardial cell injury. RESULTS R5 HIV-1 gp120 damaged myocardial cells and induced p38 MAPK phosphorylation. SB blocked R5 HIV-1 gp120-induced myocardial cell injury. DAPTA blocked R5 HIV-1 gp120-mediated p38 MAPK phosphorylation, while MK801 did not. DAPTA inhibited R5 HIV-1 gp120-induced myocardial cell injury. CONCLUSION Our data indicate that R5 HIV-1 gp120 activated p38 MAPK to trigger myocardial cell injury by the CCR5 coreceptor.
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Affiliation(s)
- Rui Gao
- The Key Laboratory of Fujian Province University on Ion Channel and Signal Transduction in Cardiovascular Disease, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China.,Department of Pathology, Fujian Provincial Hospital, Provincial Clinical Medical College of Fujian Medical University, Fuzhou, China
| | - Qiujuan Fang
- The Key Laboratory of Fujian Province University on Ion Channel and Signal Transduction in Cardiovascular Disease, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China,
| | - Xi Zhang
- Department of Nursing, Fujian Provincial Hospital, Provincial Clinical Medical College of Fujian Medical University, Fuzhou, China
| | - Qin Xu
- School of Nursing, Fujian Medical University, Fuzhou, China
| | - Hanhui Ye
- Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, China
| | - Wenyan Guo
- The Key Laboratory of Fujian Province University on Ion Channel and Signal Transduction in Cardiovascular Disease, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Jiao He
- The Key Laboratory of Fujian Province University on Ion Channel and Signal Transduction in Cardiovascular Disease, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Yahong Chen
- Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, China
| | - Ruixing Wang
- The Key Laboratory of Fujian Province University on Ion Channel and Signal Transduction in Cardiovascular Disease, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Zhijuan Wu
- The Key Laboratory of Fujian Province University on Ion Channel and Signal Transduction in Cardiovascular Disease, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Jing Yu
- The Key Laboratory of Fujian Province University on Ion Channel and Signal Transduction in Cardiovascular Disease, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
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202
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Neutralization-guided design of HIV-1 envelope trimers with high affinity for the unmutated common ancestor of CH235 lineage CD4bs broadly neutralizing antibodies. PLoS Pathog 2019; 15:e1008026. [PMID: 31527908 PMCID: PMC6764681 DOI: 10.1371/journal.ppat.1008026] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/27/2019] [Accepted: 08/12/2019] [Indexed: 11/19/2022] Open
Abstract
The CD4 binding site (CD4bs) of the HIV-1 envelope glycoprotein is susceptible to multiple lineages of broadly neutralizing antibodies (bnAbs) that are attractive to elicit with vaccines. The CH235 lineage (VH1-46) of CD4bs bnAbs is particularly attractive because the most mature members neutralize 90% of circulating strains, do not possess long HCDR3 regions, and do not contain insertions and deletions that may be difficult to induce. We used virus neutralization to measure the interaction of CH235 unmutated common ancestor (CH235 UCA) with functional Env trimers on infectious virions to guide immunogen design for this bnAb lineage. Two Env mutations were identified, one in loop D (N279K) and another in V5 (G458Y), that acted synergistically to render autologous CH505 transmitted/founder virus susceptible to neutralization by CH235 UCA. Man5-enriched N-glycans provided additional synergy for neutralization. CH235 UCA bound with nanomolar affinity to corresponding soluble native-like Env trimers as candidate immunogens. A cryo-EM structure of CH235 UCA bound to Man5-enriched CH505.N279K.G458Y.SOSIP.664 revealed interactions of the antibody light chain complementarity determining region 3 (CDR L3) with the engineered Env loops D and V5. These results demonstrate that virus neutralization can directly inform vaccine design and suggest a germline targeting and reverse engineering strategy to initiate and mature the CH235 bnAb lineage. Despite a wealth of information on the epitopes, ontogeny, structure and maturation pathways of multiple epitope classes of HIV-1 broadly neutralizing antibodies (bnAbs), there has been little progress eliciting similar antibodies by vaccination. One major contributing factor is the failure of many candidate immunogens to engage germline reverted forms of bnAbs, making it unlikely that they will provide adequate stimulation of appropriate naïve B cells to initiate bnAb lineages. Here we used virus neutralization to identify two point mutations and a modified glycan profile that together render HIV-1 CH505 Env-pseudotyped virus highly susceptible to neutralization by a germline-reverted form of the CH235 lineage of CD4 binding site (CD4bs) bnAbs. These same modifications permit strong binding of corresponding soluble native-like CH505 Env trimers to germline-reverted CH235. These observations provide a conceptual framework for the design and testing of novel immunogens that aim to elicit the CH235 bnAb lineage.
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203
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Abstract
Neutralizing antibodies against human immunodeficiency virus subtype 1 (HIV-1) bind to its envelope glycoprotein (Env). Half of the molecular mass of Env is carbohydrate making it one of the most heavily glycosylated proteins known in nature. HIV-1 Env glycans are derived from the host and present a formidable challenge for host anti-glycan antibody induction. Anti-glycan antibody induction is challenging because anti-HIV-1 glycan antibodies should recognize Env antigen while not acquiring autoreactivity. Thus, the glycan network on HIV-1 Env is referred to as the glycan shield. Despite the challenges presented by immune recognition of host-derived glycans, neutralizing antibodies capable of binding the glycans on HIV-1 Env can be generated by the host immune system in the setting of HIV-1 infection. In particular, a cluster of high mannose glycans, including an N-linked glycan at position 332, form the high mannose patch and are targeted by a variety of broadly neutralizing antibodies. These high mannose patch-directed HIV-1 antibodies can be categorized into distinct categories based on their antibody paratope structure, neutralization activity, and glycan and peptide reactivity. Below we will compare and contrast each of these classes of HIV-1 glycan-dependent antibodies and describe vaccine design efforts to elicit each of these antibody types.
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204
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Hollingsworth LR, Lemkul JA, Bevan DR, Brown AM. HIV-1 Env gp41 Transmembrane Domain Dynamics Are Modulated by Lipid, Water, and Ion Interactions. Biophys J 2019; 115:84-94. [PMID: 29972814 DOI: 10.1016/j.bpj.2018.05.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 05/04/2018] [Accepted: 05/21/2018] [Indexed: 12/20/2022] Open
Abstract
The gp41 transmembrane domain (TMD) of the envelope glycoprotein of the human immunodeficiency virus modulates the conformation of the viral envelope spike, the only druggable target on the surface of the virion. Targeting the envelope glycoprotein with small-molecule and antibody therapies requires an understanding of gp41 TMD dynamics, which is often challenging given the difficulties in describing native membrane properties. Here, atomistic molecular dynamics simulations of a trimeric, prefusion gp41 TMD in a model, asymmetric viral membrane that mimics the native viral envelope were performed. Water and chloride ions were observed to permeate the membrane and interact with the highly conserved arginine bundle, (R696)3, at the center of the membrane and influenced TMD stability by creating a network of hydrogen bonds and electrostatic interactions. We propose that this (R696)3 - water - anion network plays an important role in viral fusion with the host cell by modulating protein conformational changes within the membrane. Additionally, R683 and R707 at the exofacial and cytofacial membrane-water interfaces, respectively, are anchored in the lipid headgroup region and serve as a junction point for stabilization of the termini. The membrane thins as a result of the tilting of the gp41 trimer with nearby lipids increasing in volume, leading to an entropic driving force for TMD conformational change. These results provide additional detail and perspective on the influence of certain lipid types on TMD dynamics and a rationale for targeting key residues of the TMD for therapeutic design. These insights into the molecular details of TMD membrane anchoring will build toward a greater understanding of the dynamics that lead to viral fusion with the host cell.
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Affiliation(s)
| | - Justin A Lemkul
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia; Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia
| | - David R Bevan
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia; Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia
| | - Anne M Brown
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia; Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia; University Libraries, Virginia Tech, Blacksburg, Virginia.
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205
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Developments in single-molecule and single-particle fluorescence-based approaches for studying viral envelope glycoprotein dynamics and membrane fusion. Adv Virus Res 2019; 104:123-146. [PMID: 31439147 DOI: 10.1016/bs.aivir.2019.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Fusion of viral and cellular membranes is an essential step in the entry pathway of all enveloped viruses. This is a dynamic and multistep process, which has been extensively studied, resulting in the endpoints of the reaction being firmly established, and many essential cellular factors identified. What remains is to elucidate the dynamic events that underlie this process, including the order and timing of glycoprotein conformational changes, receptor-binding events, and movement of the glycoprotein on the surface of the virion. Due to the inherently asynchronous nature of these dynamics, there has been an increased focus on the study of single virions and single molecules. These techniques provide researchers the high precision and resolution necessary to bridge the gaps in our understanding of viral membrane fusion. This review highlights the advancement of single-molecule and single-particle fluorescence-based techniques, with a specific focus on how these techniques have been used to study the dynamic nature of the viral fusion pathway.
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206
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Abstract
Single-molecule Förster resonance energy transfer (smFRET) imaging has emerged as a powerful tool to probe conformational dynamics of viral proteins, identify novel structural intermediates that are hiding in averaging population-based measurements, permit access to the energetics of transitions and as such to the precise molecular mechanisms of viral replication. One strength of smFRET is the capability of characterizing biological molecules in their fully hydrated/native state, which are not necessarily available to other structural methods. Elegant experimental design for physiologically relevant conditions, such as intact virions, has permitted the detection of previously unknown conformational states of viral glycoproteins, revealed asymmetric intermediates, and allowed access to the real-time imaging of conformational changes during viral fusion. As more laboratories are applying smFRET, our understanding of the molecular mechanisms and the dynamic nature of viral proteins throughout the virus life cycle are predicted to improve and assist the development of novel antiviral therapies and vaccine design.
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Affiliation(s)
- Maolin Lu
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, United States.
| | - Xiaochu Ma
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, United States
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, United States.
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207
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Duerr R, Gorny MK. V2-Specific Antibodies in HIV-1 Vaccine Research and Natural Infection: Controllers or Surrogate Markers. Vaccines (Basel) 2019; 7:vaccines7030082. [PMID: 31390725 PMCID: PMC6789775 DOI: 10.3390/vaccines7030082] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 07/26/2019] [Accepted: 07/27/2019] [Indexed: 12/20/2022] Open
Abstract
Most human immunodeficiency virus (HIV) vaccine trials have lacked efficacy and empirical vaccine lead targets are scarce. Thus far, the only independent correlate of reduced risk of HIV-1 acquisition in humans is elevated levels of V2-specific antibodies identified in the modestly protective RV144 vaccine trial. Ten years after RV144, human and non-human primate vaccine studies have reassessed the potential contribution of V2-specific antibodies to vaccine efficacy. In addition, studies of natural HIV-1 infection in humans have provided insight into the development of V1V2-directed antibody responses and their impact on clinical parameters and disease progression. Functionally diverse anti-V2 monoclonal antibodies were isolated and their structurally distinct V2 epitope regions characterized. After RV144, a plethora of research studies were performed using different model systems, immunogens, protocols, and challenge viruses. These diverse studies failed to provide a clear picture regarding the contribution of V2 antibodies to vaccine efficacy. Here, we summarize the biological functions and clinical findings associated with V2-specific antibodies and discuss their impact on HIV vaccine research.
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Affiliation(s)
- Ralf Duerr
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA.
| | - Miroslaw K Gorny
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
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208
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Brinkkemper M, Sliepen K. Nanoparticle Vaccines for Inducing HIV-1 Neutralizing Antibodies. Vaccines (Basel) 2019; 7:E76. [PMID: 31362378 PMCID: PMC6789800 DOI: 10.3390/vaccines7030076] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 07/23/2019] [Accepted: 07/25/2019] [Indexed: 01/01/2023] Open
Abstract
The enormous sequence diversity between human immunodeficiency virus type 1 (HIV-1) strains poses a major roadblock for generating a broadly protective vaccine. Many experimental HIV-1 vaccine efforts are therefore aimed at eliciting broadly neutralizing antibodies (bNAbs) that are capable of neutralizing the majority of circulating HIV-1 strains. The envelope glycoprotein (Env) trimer on the viral membrane is the sole target of bNAbs and the key component of vaccination approaches aimed at eliciting bNAbs. Multimeric presentation of Env on nanoparticles often plays a critical role in these strategies. Here, we will discuss the different aspects of nanoparticles in Env vaccination, including recent insights in immunological processes underlying their perceived advantages, the different nanoparticle platforms and the various immunogenicity studies that employed nanoparticles to improve (neutralizing) antibody responses against Env.
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Affiliation(s)
- Mitch Brinkkemper
- Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands
| | - Kwinten Sliepen
- Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands.
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209
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Zhou H, Chen Y, Zhang S, Niu P, Qin K, Jia W, Huang B, Zhang S, Lan J, Zhang L, Tan W, Wang X. Structural definition of a neutralization epitope on the N-terminal domain of MERS-CoV spike glycoprotein. Nat Commun 2019; 10:3068. [PMID: 31296843 PMCID: PMC6624210 DOI: 10.1038/s41467-019-10897-4] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 06/05/2019] [Indexed: 02/05/2023] Open
Abstract
Most neutralizing antibodies against Middle East respiratory syndrome coronavirus (MERS-CoV) target the receptor-binding domain (RBD) of the spike glycoprotein and block its binding to the cellular receptor dipeptidyl peptidase 4 (DPP4). The epitopes and mechanisms of mAbs targeting non-RBD regions have not been well characterized yet. Here we report the monoclonal antibody 7D10 that binds to the N-terminal domain (NTD) of the spike glycoprotein and inhibits the cell entry of MERS-CoV with high potency. Structure determination and mutagenesis experiments reveal the epitope and critical residues on the NTD for 7D10 binding and neutralization. Further experiments indicate that the neutralization by 7D10 is not solely dependent on the inhibition of DPP4 binding, but also acts after viral cell attachment, inhibiting the pre-fusion to post-fusion conformational change of the spike. These properties give 7D10 a wide neutralization breadth and help explain its synergistic effects with several RBD-targeting antibodies. Antibodies that target the N-terminal domain (NTD) of the MERS-CoV spike remain poorly characterized. Here, Zhou et al. report the structural and functional analysis of the NTD-targeting mAb 7D10 and show that it synergizes with antibodies targeting the receptor-binding domain against different MERS-CoV strains.
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Affiliation(s)
- Haixia Zhou
- The Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Collaborative Innovation Center for Biotherapy, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Yingzhu Chen
- Key Laboratory of Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, China CDC, 102206, Beijing, China.,Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Clinical Laboratory, Peking University Cancer Hospital & Institute, 100142, Beijing, China
| | - Shuyuan Zhang
- The Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Collaborative Innovation Center for Biotherapy, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Peihua Niu
- Key Laboratory of Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, China CDC, 102206, Beijing, China
| | - Kun Qin
- Key Laboratory of Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, China CDC, 102206, Beijing, China
| | - Wenxu Jia
- Comprehensive AIDS Research Center, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, 100084, Beijing, China
| | - Baoying Huang
- Key Laboratory of Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, China CDC, 102206, Beijing, China
| | - Senyan Zhang
- The Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Collaborative Innovation Center for Biotherapy, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Jun Lan
- The Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Collaborative Innovation Center for Biotherapy, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Linqi Zhang
- Comprehensive AIDS Research Center, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, 100084, Beijing, China
| | - Wenjie Tan
- Key Laboratory of Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, China CDC, 102206, Beijing, China.
| | - Xinquan Wang
- The Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Collaborative Innovation Center for Biotherapy, School of Life Sciences, Tsinghua University, 100084, Beijing, China. .,Collaborative Innovation Center for Biotherapy, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, 610065, Chengdu, China.
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210
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Shen Z, Liu S, Li X, Wan Z, Mao Y, Chen C, Liu W. Conformational change within the extracellular domain of B cell receptor in B cell activation upon antigen binding. eLife 2019; 8:42271. [PMID: 31290744 PMCID: PMC6620044 DOI: 10.7554/elife.42271] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 06/27/2019] [Indexed: 12/20/2022] Open
Abstract
B lymphocytes use B cell receptors (BCRs) to recognize antigens. It is still not clear how BCR transduces antigen-specific physical signals upon binding across cell membrane for the conversion to chemical signals, triggering downstream signaling cascades. It is hypothesized that through a series of conformational changes within BCR, antigen engagement in the extracellular domain of BCR is transduced to its intracellular domain. By combining site-specific labeling methodology and FRET-based assay, we monitored conformational changes in the extracellular domains within BCR upon antigen engagement. Conformational changes within heavy chain of membrane-bound immunoglobulin (mIg), as well as conformational changes in the spatial relationship between mIg and Igβ were observed. These conformational changes were correlated with the strength of BCR activation and were distinct in IgM- and IgG-BCR. These findings provide molecular mechanisms to explain the fundamental aspects of BCR activation and a framework to investigate ligand-induced molecular events in immune receptors.
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Affiliation(s)
- Zhixun Shen
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
| | - Sichen Liu
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
| | - Xinxin Li
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
| | - Zhengpeng Wan
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
| | - Youxiang Mao
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
| | - Chunlai Chen
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing, China
| | - Wanli Liu
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
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211
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Zolla-Pazner S, Alvarez R, Kong XP, Weiss S. Vaccine-induced V1V2-specific antibodies control and or protect against infection with HIV, SIV and SHIV. Curr Opin HIV AIDS 2019; 14:309-317. [PMID: 30994501 PMCID: PMC6542703 DOI: 10.1097/coh.0000000000000551] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
PURPOSE OF REVIEW In humans, only one independent immunologic correlate of reduced risk of HIV infection has been identified: a robust antibody (Ab) response to the V1V2 domain of the gp120 envelope (Env) protein. In recent years, the presence and level of V1V2-specific Abs has also been correlated with protection from SIV and SHIV infections. Here, we review the multitude of studies showing the in-vivo protective effects of V1V2 Abs and review their immunologic characteristics and antiviral functions. RECENT FINDINGS Structural and immunologic studies have defined four epitope families in the V1V2 domain: one epitope family, V2q, which preferentially presents as a quaternary structure of the Env trimer, and another epitope family (V2qt) which requires the quaternary trimeric Env structure; these two epitope types are recognized by two families of monoclonal Abs (mAbs)-V2q-specific and V2qt-specific mAbs-which display broad and potent neutralizing activity. A third epitope family, V2i, is present as a discontinuous conformational structure that overlays the α4β7 integrin binding motif, and a fourth epitope family (V2p) exists on V2 peptides. Antibodies specific for V2i and V2p epitopes display only poor neutralizing activity but effectively mediate other antiviral activities and have been correlated with control of and/or protection from HIV, SIV and SHIV. Notably, V2q and V2qt Abs have not been induced by any vaccines, but V2p and V2i Abs have been readily induced with various vaccines in nonhuman primates and humans. SUMMARY The correlation of vaccine-induced V2p and V2i Abs with protection from HIV, SIV and SHIV suggests that these Ab types are extremely important to induce with prophylactic vaccines.
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Affiliation(s)
- Susan Zolla-Pazner
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai
| | - Raymond Alvarez
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai
| | - Xiang-Peng Kong
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Svenja Weiss
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai
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212
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Han Q, Jones JA, Nicely NI, Reed RK, Shen X, Mansouri K, Louder M, Trama AM, Alam SM, Edwards RJ, Bonsignori M, Tomaras GD, Korber B, Montefiori DC, Mascola JR, Seaman MS, Haynes BF, Saunders KO. Difficult-to-neutralize global HIV-1 isolates are neutralized by antibodies targeting open envelope conformations. Nat Commun 2019; 10:2898. [PMID: 31263112 PMCID: PMC6602974 DOI: 10.1038/s41467-019-10899-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 06/03/2019] [Indexed: 12/21/2022] Open
Abstract
The HIV-1 envelope (Env) is the target for neutralizing antibodies and exists on the surface of virions in open or closed conformations. Difficult-to-neutralize viruses (tier 2) express Env in a closed conformation antigenic for broadly neutralizing antibodies (bnAbs) but not for third variable region (V3) antibodies. Here we show that select V3 macaque antibodies elicited by Env vaccination can neutralize 26% of otherwise tier 2 HIV-1 isolates in standardized virus panels. The V3 antibodies only bound to Env in its open conformation. Thus, Envs on tier 2 viruses sample a state where the V3 loop is not in its closed conformation position. Envelope second variable region length, glycosylation sites and V3 amino acids were signatures of neutralization sensitivity. This study determined that open conformations of Env with V3 exposed are present on a subset of otherwise neutralization-resistant virions, therefore neutralization of tier 2 HIV-1 does not always indicate bnAb induction.
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Affiliation(s)
- Qifeng Han
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - Julia A Jones
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - Nathan I Nicely
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - Rachel K Reed
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - Xiaoying Shen
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - Katayoun Mansouri
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
- Department of Cell Biology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Mark Louder
- Vaccine Research Center, National Instiftute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, MD, 20892, USA
| | - Ashley M Trama
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - S Munir Alam
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - Robert J Edwards
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
- Department of Cell Biology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Mattia Bonsignori
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - Georgia D Tomaras
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
- Department of Surgery, Duke University Medical Center, Durham, NC, 27710, USA
- Department of Microbiology and Molecular Genetics, Duke University Medical Center, Durham, NC, 27710, USA
- Department of Immunology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Bette Korber
- Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - David C Montefiori
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
- Department of Surgery, Duke University Medical Center, Durham, NC, 27710, USA
| | - John R Mascola
- Vaccine Research Center, National Instiftute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, MD, 20892, USA
| | - Michael S Seaman
- Center for Virology and Vaccine Research, Israel Deaconess Medical Center, Boston, MA, 02115, USA
| | - Barton F Haynes
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA.
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA.
- Department of Immunology, Duke University Medical Center, Durham, NC, 27710, USA.
| | - Kevin O Saunders
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA.
- Department of Surgery, Duke University Medical Center, Durham, NC, 27710, USA.
- Department of Microbiology and Molecular Genetics, Duke University Medical Center, Durham, NC, 27710, USA.
- Department of Immunology, Duke University Medical Center, Durham, NC, 27710, USA.
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213
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CD4 Expression and Env Conformation Are Critical for HIV-1 Restriction by SERINC5. J Virol 2019; 93:JVI.00544-19. [PMID: 31043528 DOI: 10.1128/jvi.00544-19] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 04/25/2019] [Indexed: 12/29/2022] Open
Abstract
Serine incorporator 5 (SERINC5) is a recently identified restriction factor that strongly blocks HIV-1 entry but is counteracted by Nef. Notably, tier 1 HIV-1 Env proteins are sensitive to SERINC5, whereas the majority of tier 2/3 Env proteins are resistant to SERINC5, when viruses are produced from CD4-negative cells and tested by a single-round replication assay. Here, we investigated the Env-dependent SERINC5 antiviral mechanism by comparing tier 1 NL Env with tier 3 AD8 Env proteins. We found that when NL and AD8 viruses were inoculated into CD4+ T cells and human peripheral blood mononuclear cells (PBMCs), the propagation of the two viruses was restricted to a similar level when Nef was not expressed. Using a bimolecular fluorescence complementation (BiFC) assay, we detected Env-Env association and Env-SERINC5 interactions. A much greater level of NL Env-SERINC5 interactions was detected than was AD8 Env-SERINC5 interactions, which was further validated by immunoprecipitation assays. In addition, SERINC5 dissociated the NL Env trimeric complex more effectively than the AD8 Env trimeric complex when CD4 was not expressed. However, when CD4 was expressed, SERINC5 became more capable of interacting with AD8 Env and dissociating its trimeric complex. Moreover, AD8 and several other tier 2/3 viruses produced in the presence of CD4 became sensitive to SERINC5 when measured by the single-round replication assay. Because tier 1 and tier 2/3 Env trimers have open and closed conformations, respectively, and CD4 opens the closed conformation, we conclude that SERINC5 selectively dissociates Env trimers with an open conformation to restrict HIV-1 replication.IMPORTANCE Restriction factors provide the first line of defense against retrovirus infection by posing several blocks to the viral replication cycle. SERINC5 is a novel restriction factor that strongly blocks HIV-1 entry, although it is counteracted by Nef. Currently, it is still unclear how HIV-1 entry is blocked by SERINC5. Notably, this entry block is dependent on viral Env proteins. Laboratory-adapted HIV-1 strains are sensitive, whereas primary isolates are highly resistant to SERINC5. Env proteins mediate virus entry via extensive conformational rearrangements from a closed ground state to a CD4-bound open state. We detected Env-Env associations and Env-SERINC5 interactions in live cells by a novel bimolecular fluorescence assay. We demonstrate that CD4 expression increases the Env sensitivity to SERINC5 and allows SERINC5 to dissociate the Env complex, suggesting that SERINC5 restriction is dependent on Env conformation. Our results provide new insights into the poorly defined Env-dependent SERINC5 antiviral mechanism.
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214
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Chen B. Molecular Mechanism of HIV-1 Entry. Trends Microbiol 2019; 27:878-891. [PMID: 31262533 DOI: 10.1016/j.tim.2019.06.002] [Citation(s) in RCA: 199] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 05/20/2019] [Accepted: 06/05/2019] [Indexed: 11/19/2022]
Abstract
HIV-1 envelope glycoprotein [Env; trimeric (gp160)3 cleaved to (gp120/gp41)3] attaches the virion to a susceptible cell and induces fusion of viral and cell membranes to initiate infection. It interacts with the primary receptor CD4 and coreceptor (e.g., chemokine receptor CCR5 or CXCR4) to allow viral entry by triggering large structural rearrangements and unleashing the fusogenic potential of gp41 to induce membrane fusion. Recent advances in structural biology of HIV-1 Env and its complexes with the cellular receptors have revealed molecular details of HIV-1 entry and yielded new mechanistic insights. In this review, I summarize our latest understanding of the HIV-1 membrane fusion process and discuss possible pathways for productive viral entry.
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Affiliation(s)
- Bing Chen
- Division of Molecular Medicine, Boston Children's Hospital, and Department of Pediatrics, Harvard Medical School, 3 Blackfan Street, Boston, MA 02115, USA.
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215
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Broadly resistant HIV-1 against CD4-binding site neutralizing antibodies. PLoS Pathog 2019; 15:e1007819. [PMID: 31194843 PMCID: PMC6592578 DOI: 10.1371/journal.ppat.1007819] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 06/25/2019] [Accepted: 05/07/2019] [Indexed: 01/15/2023] Open
Abstract
Recently identified broadly neutralizing antibodies (bnAbs) show great potential for clinical interventions against HIV-1 infection. However, resistant strains may impose substantial challenges. Here, we report on the identification and characterization of a panel of HIV-1 strains with broad and potent resistance against a large number of bnAbs, particularly those targeting the CD4-binding site (CD4bs). Site-directed mutagenesis revealed that several key epitope mutations facilitate resistance and are located in the inner domain, loop D, and β23/loop V5/β24 of HIV-1 gp120. The resistance is largely correlated with binding affinity of antibodies to the envelope trimers expressed on the cell surface. Our results therefore demonstrate the existence of broadly resistant HIV-1 strains against CD4bs neutralizing antibodies. Treatment strategies based on the CD4bs bnAbs must overcome such resistance to achieve optimal clinical outcomes. Recently identified broadly neutralizing antibodies (bnAbs) show great potential for clinical interventions against HIV-1 infection. Among the bnAbs isolated to date, those targeting the CD4bs are the most abundant and thoroughly studied as they disrupt the crucial step of viral interaction with the cellular receptor molecule CD4. Despite the superior potency and breadth of these CD4bs bnAbs, each fails to neutralize a small but significant portion of pseudotyped virus panels. Here, we report on the identification and characterization of a panel of HIV-1 strains with broad and potent resistance against a large number of bnAbs, particularly those targeting the CD4bs. Resistance is largely attributed to mutated residues within the epitopes or steric hindrance imposed by the bulky side-chain or glycan shield of the mutated residues, and is largely correlated with reduced binding avidity of the antibody to the quaternary trimeric envelope protein expressed on the surface of the transfected cells. Treatment strategies based on the CD4bs bnAbs therefore must overcome such resistance to achieve optimal clinical outcomes.
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216
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Bignon EA, Albornoz A, Guardado-Calvo P, Rey FA, Tischler ND. Molecular organization and dynamics of the fusion protein Gc at the hantavirus surface. eLife 2019; 8:46028. [PMID: 31180319 PMCID: PMC6609335 DOI: 10.7554/elife.46028] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 06/10/2019] [Indexed: 01/01/2023] Open
Abstract
The hantavirus envelope glycoproteins Gn and Gc mediate virion assembly and cell entry, with Gc driving fusion of viral and endosomal membranes. Although the X-ray structures and overall arrangement of Gn and Gc on the hantavirus spikes are known, their detailed interactions are not. Here we show that the lateral contacts between spikes are mediated by the same 2-fold contacts observed in Gc crystals at neutral pH, allowing the engineering of disulfide bonds to cross-link spikes. Disrupting the observed dimer interface affects particle assembly and overall spike stability. We further show that the spikes display a temperature-dependent dynamic behavior at neutral pH, alternating between ‘open’ and ‘closed’ forms. We show that the open form exposes the Gc fusion loops but is off-pathway for productive Gc-induced membrane fusion and cell entry. These data also provide crucial new insights for the design of optimized Gn/Gc immunogens to elicit protective immune responses. Hantaviruses infect rodents and other small mammals, but do not harm them. When transmitted to humans, often through rodent urine, feces or saliva, they can cause serious and even fatal diseases. Currently, there are no known methods that effectively prevent hantavirus infections or treat the diseases that they cause. During an infection, viruses invade the cells of their host. A hantavirus interacts with target cells through proteins on its surface called Gn and Gc glycoproteins. Previous work has shown that these glycoproteins are organized in bundles of four Gn and four Gc proteins, termed spikes, which project from the membrane that surrounds the virus. The Gc protein changes shape when it is activated and exposes a hidden region that can insert into the membrane of the target cell. The Gc proteins then change shape again to force the cell to fuse with the viral membrane. This process allows the virus to be taken up into the cell, where it can replicate. While the structures of each viral glycoprotein have been determined in isolation, it was not known how they interact within the Gn/Gc spike. Such information is crucial to understand how the viruses infect cells and which areas are exposed to the immune system of the host – and so could be targeted by antiviral treatments. Bignon et al. have now identified the molecular contacts that occur between spikes and interconnect them into a grid-like lattice on the surface of the virus. Genetically altering specific sections of the Gc glycoprotein strengthened or weakened these contacts, which correspondingly increased or decreased how stable the spike was. Preventing the contacts from forming resulted in cells releasing fewer virus-like particles. Bignon et al. also show that at the body temperature of mammals, the shape of the spike fluctuates between an ‘open’ form that exposes the region of Gc that inserts into the cell membrane, and a ‘closed’ form that hides this region. However, when Gc is activated, the open form becomes unable to cause the viral and cell membranes to fuse together. Together, the results presented by Bignon et al. help us to understand how changes to the hantavirus surface enable the virus to infect cells. This knowledge will help researchers to design vaccines that protect against hantavirus infections.
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Affiliation(s)
- Eduardo A Bignon
- Laboratorio de Virología Molecular, Fundación Ciencia & Vida, Santiago, Chile
| | - Amelina Albornoz
- Laboratorio de Virología Molecular, Fundación Ciencia & Vida, Santiago, Chile
| | - Pablo Guardado-Calvo
- Structural Virology Unit, Virology Department, Institut Pasteur, CNRS UMR 3569, Paris, France
| | - Félix A Rey
- Structural Virology Unit, Virology Department, Institut Pasteur, CNRS UMR 3569, Paris, France
| | - Nicole D Tischler
- Laboratorio de Virología Molecular, Fundación Ciencia & Vida, Santiago, Chile
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217
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Dowd KA, Pierson TC. The Many Faces of a Dynamic Virion: Implications of Viral Breathing on Flavivirus Biology and Immunogenicity. Annu Rev Virol 2019; 5:185-207. [PMID: 30265634 DOI: 10.1146/annurev-virology-092917-043300] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Flaviviruses are arthropod-borne RNA viruses that are a significant threat to global health due to their widespread distribution, ability to cause severe disease in humans, and capacity for explosive spread following introduction into new regions. Members of this genus include dengue, tick-borne encephalitis, yellow fever, and Zika viruses. Vaccination has been a highly successful means to control flaviviruses, and neutralizing antibodies are an important component of a protective immune response. High-resolution structures of flavivirus structural proteins and virions, alone and in complex with antibodies, provide a detailed understanding of viral fusion mechanisms and virus-antibody interactions. However, mounting evidence suggests these structures provide only a snapshot of an otherwise structurally dynamic virus particle. The contribution of the structural ensemble arising from viral breathing to the biology, antigenicity, and immunity of flaviviruses is discussed, including implications for the development and evaluation of flavivirus vaccines.
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Affiliation(s)
- Kimberly A Dowd
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA; ,
| | - Theodore C Pierson
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA; ,
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218
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Anand SP, Grover JR, Tolbert WD, Prévost J, Richard J, Ding S, Baril S, Medjahed H, Evans DT, Pazgier M, Mothes W, Finzi A. Antibody-Induced Internalization of HIV-1 Env Proteins Limits Surface Expression of the Closed Conformation of Env. J Virol 2019; 93:e00293-19. [PMID: 30894474 PMCID: PMC6532100 DOI: 10.1128/jvi.00293-19] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 03/16/2019] [Indexed: 01/10/2023] Open
Abstract
To minimize immune responses against infected cells, HIV-1 limits the surface expression of its envelope glycoprotein (Env). Here, we demonstrate that this mechanism is specific for the Env conformation and affects the efficiency of antibody-dependent cellular cytotoxicity (ADCC). Using flow cytometry and confocal microscopy, we show that broadly neutralizing antibodies (bNAbs) targeting the "closed" conformation of Env induce its internalization from the surface. In contrast, non-neutralizing antibodies (nNAbs) are displayed on the cell surface for prolonged period of times. The bNAb-induced Env internalization can be decreased by blocking dynamin function, which translates into higher susceptibilities of infected cells to ADCC. Our results suggest that antibody-mediated Env internalization is a mechanism used by HIV-1 to evade immune responses against the "closed" conformation of Env expressed on HIV-1-infected cells.IMPORTANCE HIV-1 has evolved to acquire several strategies to limit the exposure of its envelope glycoproteins (Env) on the surface of infected cells. In this study, we show that antibody-induced Env internalization is conformation specific and reduces the susceptibility of infected cells to antibody-dependent cellular cytotoxicity (ADCC). Thus, a better understanding of this mechanism might help develop antibodies with improved capacities to mediate ADCC.
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Affiliation(s)
- Sai Priya Anand
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Jonathan R Grover
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - William D Tolbert
- Infectious Diseases Division, Department of Medicine of Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | | | - Shilei Ding
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Sophie Baril
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
| | | | - David T Evans
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, USA
- Wisconsin National Primate Research Center, University of Wisconsin, Madison, Wisconsin, USA
| | - Marzena Pazgier
- Infectious Diseases Division, Department of Medicine of Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
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219
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Balasubramaniam M, Pandhare J, Dash C. Immune Control of HIV. JOURNAL OF LIFE SCIENCES (WESTLAKE VILLAGE, CALIF.) 2019; 1:4-37. [PMID: 31468033 PMCID: PMC6714987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The human immunodeficiency virus (HIV) infection of the immune cells expressing the cluster of differentiation 4 cell surface glycoprotein (CD4+ cells) causes progressive decline of the immune system and leads to the acquired immunodeficiency syndrome (AIDS). The ongoing global HIV/AIDS pandemic has already claimed over 35 million lives. Even after 37 years into the epidemic, neither a cure is available for the 37 million people living with HIV (PLHIV) nor is a vaccine discovered to avert the millions of new HIV infections that continue to occur each year. If left untreated, HIV infection typically progresses to AIDS and, ultimately, causes death in a majority of PLHIV. The recommended combination antiretroviral therapy (cART) suppresses virus replication and viremia, prevents or delays progression to AIDS, reduces transmission rates, and lowers HIV-associated mortality and morbidity. However, because cART does not eliminate HIV, and an enduring pool of infected resting memory CD4+ T cells (latent HIV reservoir) is established early on, any interruption to cART leads to a relapse of viremia and disease progression. Hence, strict adherence to a life-long cART regimen is mandatory for managing HIV infection in PLHIV. The HIV-1-specific cytotoxic T cells expressing the CD8 glycoprotein (CD8+ CTL) limit the virus replication in vivo by recognizing the viral antigens presented by human leukocyte antigen (HLA) class I molecules on the infected cell surface and killing those cells. Nevertheless, CTLs fail to durably control HIV-1 replication and disease progression in the absence of cART. Intriguingly, <1% of cART-naive HIV-infected individuals called elite controllers/HIV controllers (HCs) exhibit the core features that define a HIV-1 "functional cure" outcome in the absence of cART: durable viral suppression to below the limit of detection, long-term non-progression to AIDS, and absence of viral transmission. Robust HIV-1-specific CTL responses and prevalence of protective HLA alleles associated with enduring HIV-1 control have been linked to the HC phenotype. An understanding of the molecular mechanisms underlying the CTL-mediated suppression of HIV-1 replication and disease progression in HCs carrying specific protective HLA alleles may yield promising insights towards advancing the research on HIV cure and prophylactic HIV vaccine.
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Affiliation(s)
- Muthukumar Balasubramaniam
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, TN – 37208. USA
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN – 37208. USA
| | - Jui Pandhare
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, TN – 37208. USA
- School of Graduate Studies and Research, Meharry Medical College, Nashville, TN – 37208. USA
| | - Chandravanu Dash
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, TN – 37208. USA
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN – 37208. USA
- School of Graduate Studies and Research, Meharry Medical College, Nashville, TN – 37208. USA
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220
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Effects of the SOS (A501C/T605C) and DS (I201C/A433C) Disulfide Bonds on HIV-1 Membrane Envelope Glycoprotein Conformation and Function. J Virol 2019; 93:JVI.00304-19. [PMID: 30944182 DOI: 10.1128/jvi.00304-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 03/29/2019] [Indexed: 02/06/2023] Open
Abstract
Most broadly neutralizing antibodies and many entry inhibitors target the pretriggered (state 1) conformation of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env). Here we examine two previously reported Env mutants designed to be stabilized in this conformation by the introduction of artificial disulfide bonds: A501C/T605C (called SOS) and I201C/A433C (called DS). SOS Env supported virus entry and cell-cell fusion only after exposure to a reducing agent, dithiothreitol (DTT). Deletion of the Env cytoplasmic tail improved the efficiency with which the SOS Env supported virus infection in a reducing environment. The antigenicity of the SOS Env was similar to that of the unmodified Env, except for greater sensitivity to some state 1-preferring ligands. In contrast, viruses with the DS Env were not infectious, even after DTT treatment. The proteolytic maturation of the DS Env on both cell surfaces and virions was severely compromised compared with that of the unmodified Env. The DS Env exhibited detectable cell-fusing activity when DTT was present. However, the profiles of cell-surface Env recognition and cell-cell fusion inhibition by antibodies differed for the DS Env and the unmodified Env. Thus, the DS Env appears to be stabilized in an off-pathway conformation that is nonfunctional on the virus. The SOS change exerted more subtle, context-dependent effects on Env conformation and function.IMPORTANCE The human immunodeficiency virus type 1 (HIV-1) envelope proteins (Envs) bind receptors on the host cell and change shape to allow the virus to enter the cell. Most virus-inhibiting antibodies and drugs recognize a particular shape of Env called state 1. Disulfide bonds formed by cysteine residues have been introduced into soluble forms of the flexible envelope proteins in an attempt to lock them into state 1 for use in vaccines and as research tools. We evaluated the effect of these cysteine substitutions on the ability of the membrane Env to support virus entry and on susceptibility to inhibition by antibodies and small molecules. We found that the conformation of the envelope proteins with the cysteine substitutions differed from that of the unmodified membrane envelope proteins. Awareness of these effects can assist efforts to create stable HIV-1 Env complexes that more closely resemble the state 1 conformation.
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221
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Quantifying Anti-HIV Envelope-Specific Antibodies in Plasma from HIV Infected Individuals. Viruses 2019; 11:v11060487. [PMID: 31141927 PMCID: PMC6631318 DOI: 10.3390/v11060487] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/21/2019] [Accepted: 05/25/2019] [Indexed: 12/15/2022] Open
Abstract
Quantifying HIV Envelope (Env)-specific antibodies in HIV+ plasma is useful for interpreting antibody dependent cellular cytotoxicity assay results. HIV Env, the only viral protein expressed on the surface of infected cells, has a native trimeric closed conformation on cells infected with wild-type HIV. However, CD4+ uninfected bystander cells in HIV+ cell cultures bind gp120 shed from HIV+ cells exposing CD4-induced epitopes normally hidden in native Env. We used flow-cytometry based assays to quantify antibodies in HIV+ plasma specific for native trimeric Env or gp120/CD4 conjugates using CEM.NKr.CCR5 (CEM) cells infected with HIV (iCEM) or coated with recombinant gp120 (cCEM), as a surrogate for gp120+ HIV- bystander cells. Results from both assays were compared to those of a plate-based ELISA to monomeric gp120. The levels of Env-specific antibodies to cCEM and iCEM, measured by flow cytometry, and to gp120 by ELISA were positively correlated. More antibodies in HIV+ plasma recognized the gp120 conformation exposed on cCEM than on iCEM. Comparisons of plasma from untreated progressors, treated progressors, and elite controllers revealed that antibodies to Env epitopes were the lowest in treated progressors. Plasma from elite controllers and untreated progressors had similarly high levels of Env-specific antibodies, despite elite controllers having undetectable HIV viral loads, while untreated progressors maintained high viral loads.
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222
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Gilman MSA, Furmanova-Hollenstein P, Pascual G, B van 't Wout A, Langedijk JPM, McLellan JS. Transient opening of trimeric prefusion RSV F proteins. Nat Commun 2019; 10:2105. [PMID: 31068578 PMCID: PMC6506550 DOI: 10.1038/s41467-019-09807-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 04/02/2019] [Indexed: 01/19/2023] Open
Abstract
The respiratory syncytial virus (RSV) F glycoprotein is a class I fusion protein that mediates viral entry and is a major target of neutralizing antibodies. Structures of prefusion forms of RSV F, as well as other class I fusion proteins, have revealed compact trimeric arrangements, yet whether these trimeric forms can transiently open remains unknown. Here, we perform structural and biochemical studies on a recently isolated antibody, CR9501, and demonstrate that it enhances the opening of prefusion-stabilized RSV F trimers. The 3.3 Å crystal structure of monomeric RSV F bound to CR9501, combined with analysis of over 25 previously determined RSV F structures, reveals a breathing motion of the prefusion conformation. We also demonstrate that full-length RSV F trimers transiently open and dissociate on the cell surface. Collectively, these findings have implications for the function of class I fusion proteins, as well as antibody prophylaxis and vaccine development for RSV.
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MESH Headings
- Animals
- Antibodies, Neutralizing/chemistry
- Antibodies, Neutralizing/immunology
- Antibodies, Neutralizing/metabolism
- Antibodies, Viral/chemistry
- Antibodies, Viral/immunology
- Antibodies, Viral/metabolism
- B-Lymphocytes/virology
- Chlorocebus aethiops
- Computer Simulation
- Crystallography, X-Ray
- Drug Development
- HEK293 Cells
- HeLa Cells
- Humans
- Models, Molecular
- Protein Multimerization/physiology
- Respiratory Syncytial Virus Infections/immunology
- Respiratory Syncytial Virus Infections/prevention & control
- Respiratory Syncytial Virus Infections/virology
- Respiratory Syncytial Virus Vaccines/immunology
- Respiratory Syncytial Virus, Human/isolation & purification
- Respiratory Syncytial Virus, Human/physiology
- Vero Cells
- Viral Fusion Proteins/chemistry
- Viral Fusion Proteins/immunology
- Viral Fusion Proteins/metabolism
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Affiliation(s)
- Morgan S A Gilman
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, 03755, USA
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA
| | | | - Gabriel Pascual
- Janssen Immunosciences, World Without Disease Accelerator, San Diego, CA, 92121, USA
| | - Angélique B van 't Wout
- Janssen Prevention Center, Janssen Vaccines & Prevention B.V, Leiden, CN, 2333, The Netherlands
- AlphaBiomics, London, SW4 0PA, United Kingdom
| | | | - Jason S McLellan
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA.
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223
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Braun E, Hotter D, Koepke L, Zech F, Groß R, Sparrer KM, Müller JA, Pfaller CK, Heusinger E, Wombacher R, Sutter K, Dittmer U, Winkler M, Simmons G, Jakobsen MR, Conzelmann KK, Pöhlmann S, Münch J, Fackler OT, Kirchhoff F, Sauter D. Guanylate-Binding Proteins 2 and 5 Exert Broad Antiviral Activity by Inhibiting Furin-Mediated Processing of Viral Envelope Proteins. Cell Rep 2019; 27:2092-2104.e10. [DOI: 10.1016/j.celrep.2019.04.063] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 03/11/2019] [Accepted: 04/12/2019] [Indexed: 12/13/2022] Open
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224
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Bridging Vaccine-Induced HIV-1 Neutralizing and Effector Antibody Responses in Rabbit and Rhesus Macaque Animal Models. J Virol 2019; 93:JVI.02119-18. [PMID: 30842326 PMCID: PMC6498063 DOI: 10.1128/jvi.02119-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 02/20/2019] [Indexed: 12/13/2022] Open
Abstract
Nonneutralizing antibody functions have been associated with reduced infection risk, or control of virus replication, for HIV-1 and related viruses. It is therefore critical to evaluate development of these responses throughout all stages of preclinical testing. Rabbits are conventionally used to evaluate the ability of vaccine candidates to safely elicit antibodies that bind and neutralize HIV-1. However, it remained unexplored how effectively rabbits model the development of nonneutralizing antibody responses in primates. We administered identical HIV-1 vaccine regimens to rabbits and rhesus macaques and performed detailed comparisons of vaccine-induced antibody responses. We demonstrated that nonneutralizing HIV-specific antibody responses can be studied in the rabbit model and have identified aspects of these responses that are common, and those that are unique, to rabbits and rhesus macaques. Our findings will help determine how to best utilize preclinical rabbit and rhesus macaque models to accelerate HIV vaccine candidate testing in human trials. Studies in animal models are essential prerequisites for clinical trials of candidate HIV vaccines. Small animals, such as rabbits, are used to evaluate promising strategies prior to further immunogenicity and efficacy testing in nonhuman primates. Our goal was to determine how HIV-specific vaccine-elicited antibody responses, epitope specificity, and Fc-mediated functions in the rabbit model can predict those in the rhesus macaque (RM) model. Detailed comparisons of the HIV-1-specific IgG response were performed on serum from rabbits and RM given identical modified vaccinia virus Ankara-prime/gp120-boost immunization regimens. We found that vaccine-induced neutralizing antibody, gp120-binding antibody levels and immunodominant specificities, antibody-dependent cellular phagocytosis of HIV-1 virions, and antibody-dependent cellular cytotoxicity (ADCC) responses against gp120-coated target cells were similar in rabbits and RM. However, we also identified characteristics of humoral immunity that differed across species. ADCC against HIV-infected target cells was elicited in rabbits but not in RM, and we observed differences among subdominantly targeted epitopes. Human Fc receptor binding assays and analysis of antibody-cell interactions indicated that rabbit vaccine-induced antibodies effectively recruited and activated human natural killer cells, while vaccine-elicited RM antibodies were unable to activate either human or RM NK cells. Thus, our data demonstrate that both Fc-independent and Fc-dependent functions of rabbit antibodies can be measured with commonly used in vitro assays; however, the ability of immunogenicity studies performed in rabbits to predict responses in RM will vary depending on the particular immune parameter of interest. IMPORTANCE Nonneutralizing antibody functions have been associated with reduced infection risk, or control of virus replication, for HIV-1 and related viruses. It is therefore critical to evaluate development of these responses throughout all stages of preclinical testing. Rabbits are conventionally used to evaluate the ability of vaccine candidates to safely elicit antibodies that bind and neutralize HIV-1. However, it remained unexplored how effectively rabbits model the development of nonneutralizing antibody responses in primates. We administered identical HIV-1 vaccine regimens to rabbits and rhesus macaques and performed detailed comparisons of vaccine-induced antibody responses. We demonstrated that nonneutralizing HIV-specific antibody responses can be studied in the rabbit model and have identified aspects of these responses that are common, and those that are unique, to rabbits and rhesus macaques. Our findings will help determine how to best utilize preclinical rabbit and rhesus macaque models to accelerate HIV vaccine candidate testing in human trials.
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225
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Meuser ME, Rashad AA, Ozorowski G, Dick A, Ward AB, Cocklin S. Field-Based Affinity Optimization of a Novel Azabicyclohexane Scaffold HIV-1 Entry Inhibitor. Molecules 2019; 24:molecules24081581. [PMID: 31013646 PMCID: PMC6514670 DOI: 10.3390/molecules24081581] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/19/2019] [Accepted: 04/20/2019] [Indexed: 12/22/2022] Open
Abstract
Small-molecule HIV-1 entry inhibitors are an extremely attractive therapeutic modality. We have previously demonstrated that the entry inhibitor class can be optimized by using computational means to identify and extend the chemotypes available. Here we demonstrate unique and differential effects of previously published antiviral compounds on the gross structure of the HIV-1 Env complex, with an azabicyclohexane scaffolded inhibitor having a positive effect on glycoprotein thermostability. We demonstrate that modification of the methyltriazole-azaindole headgroup of these entry inhibitors directly effects the potency of the compounds, and substitution of the methyltriazole with an amine-oxadiazole increases the affinity of the compound 1000-fold over parental by improving the on-rate kinetic parameter. These findings support the continuing exploration of compounds that shift the conformational equilibrium of HIV-1 Env as a novel strategy to improve future inhibitor and vaccine design efforts.
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Affiliation(s)
- Megan E Meuser
- Department of Biochemistry & Molecular Biology, Drexel University College of Medicine, Rooms 10307, 10309, and 10315, 245 North 15th Street, Philadelphia, PA 19102, USA.
| | - Adel A Rashad
- Department of Biochemistry & Molecular Biology, Drexel University College of Medicine, Rooms 10307, 10309, and 10315, 245 North 15th Street, Philadelphia, PA 19102, USA.
| | - Gabriel Ozorowski
- Department of Integrative Structural and Computational Biology, Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, CA 92037, USA.
| | - Alexej Dick
- Department of Biochemistry & Molecular Biology, Drexel University College of Medicine, Rooms 10307, 10309, and 10315, 245 North 15th Street, Philadelphia, PA 19102, USA.
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, CA 92037, USA.
| | - Simon Cocklin
- Department of Biochemistry & Molecular Biology, Drexel University College of Medicine, Rooms 10307, 10309, and 10315, 245 North 15th Street, Philadelphia, PA 19102, USA.
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226
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Munro JB, Lee KK. Probing Structural Variation and Dynamics in the HIV-1 Env Fusion Glycoprotein. Curr HIV Res 2019; 16:5-12. [PMID: 29268688 DOI: 10.2174/1570162x16666171222110025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 08/16/2017] [Accepted: 08/17/2017] [Indexed: 11/22/2022]
Abstract
BACKGROUND Recent advances in structural characterization of the HIV envelope glycoprotein (Env) have provided a high-resolution glimpse of the architecture of this target for neutralizing antibodies and the machinery responsible for mediating receptor binding and membrane fusion. These structures primarily capture the detailed organization of the receptor-naive, prefusion conformation of Env, but under native solution conditions Env is highly dynamic, sampling multiple conformational states as well as exhibiting local protein flexibility. METHODS Special emphasis is placed on the use of biophysical methods, including single-molecule fluorescence microscopy and hydrogen/deuterium-exchange mass spectrometry. RESULTS Using novel biophysical approaches, striking isolate-specific differences in Env's dynamic profile have been revealed that appear to underlie phenotypic differences of the viral isolates such as neutralization sensitivity and CD4 receptor reactivity. CONCLUSION Structural studies are complemented by novel biophysical investigations that enable visualization of the dynamics of HIV-1 Env under native conditions. These approaches will also enable us to gain new insights into the mechanisms of action of antibodies and drugs.
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Affiliation(s)
- James B Munro
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, United States
| | - Kelly K Lee
- Department of Medicinal Chemistry and Biological Physics Structure and Design Program, University of Washington, Seattle, WA, United States
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227
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Alsahafi N, Bakouche N, Kazemi M, Richard J, Ding S, Bhattacharyya S, Das D, Anand SP, Prévost J, Tolbert WD, Lu H, Medjahed H, Gendron-Lepage G, Ortega Delgado GG, Kirk S, Melillo B, Mothes W, Sodroski J, Smith AB, Kaufmann DE, Wu X, Pazgier M, Rouiller I, Finzi A, Munro JB. An Asymmetric Opening of HIV-1 Envelope Mediates Antibody-Dependent Cellular Cytotoxicity. Cell Host Microbe 2019; 25:578-587.e5. [PMID: 30974085 PMCID: PMC6592637 DOI: 10.1016/j.chom.2019.03.002] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 12/03/2018] [Accepted: 02/28/2019] [Indexed: 10/27/2022]
Abstract
The HIV-1 envelope glycoprotein (Env) (gp120-gp41)3 is the target for neutralizing antibodies and antibody-dependent cellular cytotoxicity (ADCC). HIV-1 Env is flexible, sampling different conformational states. Before engaging CD4, Env adopts a closed conformation (State 1) that is largely antibody resistant. CD4 binding induces an intermediate state (State 2), followed by an open conformation (State 3) that is susceptible to engagement by antibodies that recognize otherwise occluded epitopes. We investigate conformational changes in Env that induce ADCC in the presence of a small-molecule CD4-mimetic compound (CD4mc). We uncover an asymmetric Env conformation (State 2A) recognized by antibodies targeting the conserved gp120 inner domain and mediating ADCC. Sera from HIV+ individuals contain these antibodies, which can stabilize Env State 2A in combination with CD4mc. Additionally, triggering State 2A on HIV-infected primary CD4+ T cells exposes epitopes that induce ADCC. Strategies that induce this Env conformation may represent approaches to fight HIV-1 infection.
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Affiliation(s)
- Nirmin Alsahafi
- Centre de Recherche du CHUM, Montreal, QC, Canada; Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Nordine Bakouche
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA
| | - Mohsen Kazemi
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia
| | - Jonathan Richard
- Centre de Recherche du CHUM, Montreal, QC, Canada; Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
| | - Shilei Ding
- Centre de Recherche du CHUM, Montreal, QC, Canada; Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
| | - Sudipta Bhattacharyya
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia
| | - Durba Das
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia
| | - Sai Priya Anand
- Centre de Recherche du CHUM, Montreal, QC, Canada; Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, QC, Canada; Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
| | - William D Tolbert
- Infectious Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Hong Lu
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, NY, USA
| | | | | | | | - Sharon Kirk
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Bruno Melillo
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA; Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Amos B Smith
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Daniel E Kaufmann
- Centre de Recherche du CHUM, Montreal, QC, Canada; Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada; Department of Medicine, Université de Montréal, Montreal, QC, Canada; Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Xueling Wu
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, NY, USA
| | - Marzena Pazgier
- Infectious Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Isabelle Rouiller
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia.
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, QC, Canada; Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada; Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada.
| | - James B Munro
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA.
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228
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Conformation of the native HIV-1 envelope protein raises questions for vaccine design. Nature 2019; 568:321-322. [DOI: 10.1038/d41586-019-01085-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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229
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Lu M, Ma X, Castillo-Menendez LR, Gorman J, Alsahafi N, Ermel U, Terry DS, Chambers M, Peng D, Zhang B, Zhou T, Reichard N, Wang K, Grover JR, Carman BP, Gardner MR, Nikić-Spiegel I, Sugawara A, Arthos J, Lemke EA, Smith AB, Farzan M, Abrams C, Munro JB, McDermott AB, Finzi A, Kwong PD, Blanchard SC, Sodroski JG, Mothes W. Associating HIV-1 envelope glycoprotein structures with states on the virus observed by smFRET. Nature 2019; 568:415-419. [PMID: 30971821 PMCID: PMC6655592 DOI: 10.1038/s41586-019-1101-y] [Citation(s) in RCA: 160] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Accepted: 03/08/2019] [Indexed: 11/09/2022]
Abstract
The HIV-1 envelope glycoprotein (Env) trimer mediates cell entry and is
conformationally dynamic1–8. Imaging
by single-molecule fluorescence resonance energy transfer (smFRET) has revealed
that, on the surface of intact virions, mature pre-fusion Env transitions from a
pre-triggered conformation (state 1) through a default intermediate conformation
(state 2) to a conformation in which it is bound to three CD4 receptor molecules
(state 3)8–10. It is currently unclear how these
states relate to known structures. Breakthroughs in the structural
characterization of the HIV-1 Env trimer have previously been achieved by
generating soluble and proteolytically cleaved trimers of gp140 Env that are
stabilized by a disulfide bond, an isoleucine-to-proline substitution at residue
559 and a truncation at residue 664 (SOSIP.664 trimers)5,11–18.
Cryo-electron microscopy studies have been performed with C-terminally truncated
Env of the HIV-1JR-FL strain in complex with the antibody PGT15119. Both approaches have revealed similar
structures for Env. Although these structures have been presumed to represent
the pre-triggered state 1 of HIV-1 Env, this hypothesis has never directly been
tested. Here we use smFRET to compare the conformational states of Env trimers
used for structural studies with native Env on intact virus. We find that the
constructs upon which extant high-resolution structures are based predominantly
occupy downstream conformations that represent states 2 and 3. Therefore, the
structure of the pretriggered state-1 conformation of viral Env that has been
identified by smFRET and that is preferentially stabilized by many broadly
neutralizing antibodies—and thus of interest for the design of
immunogens—remains unknown.
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Affiliation(s)
- Maolin Lu
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Xiaochu Ma
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Luis R Castillo-Menendez
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Jason Gorman
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Nirmin Alsahafi
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada.,Centre de Recherche du CHUM (CRCHUM), Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Utz Ermel
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Daniel S Terry
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Michael Chambers
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Dongjun Peng
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Baoshan Zhang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Tongqing Zhou
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Nick Reichard
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Kevin Wang
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Jonathan R Grover
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Brennan P Carman
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Matthew R Gardner
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Ivana Nikić-Spiegel
- Werner Reichardt Centre for Integrative Neuroscience, University of Tuebingen, Tuebingen, Germany
| | - Akihiro Sugawara
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA
| | - James Arthos
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Edward A Lemke
- Departments of Biology and Chemistry, Pharmacy and Geosciences, Johannes Gutenberg University Mainz, Mainz, Germany.,Institute of Molecular Biology (IMB), Johannes Gutenberg University Mainz, Mainz, Germany.,Structural and Computational Biology Unit and Cell Biology and Biophysics Unit, EMBL, Heidelberg, Germany
| | - Amos B Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael Farzan
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Cameron Abrams
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, PA, USA
| | - James B Munro
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA
| | - Adrian B McDermott
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Andrés Finzi
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada.,Centre de Recherche du CHUM (CRCHUM), Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Scott C Blanchard
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA.
| | - Joseph G Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, USA. .,Department of Microbiology, Harvard Medical School, Boston, MA, USA.
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA.
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230
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Kalemera M, Mincheva D, Grove J, Illingworth CJR. Building a mechanistic mathematical model of hepatitis C virus entry. PLoS Comput Biol 2019; 15:e1006905. [PMID: 30883541 PMCID: PMC6445459 DOI: 10.1371/journal.pcbi.1006905] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 04/02/2019] [Accepted: 02/28/2019] [Indexed: 12/12/2022] Open
Abstract
The mechanism by which hepatitis C virus (HCV) gains entry into cells is a complex one, involving a broad range of host proteins. Entry is a critical phase of the viral lifecycle, and a potential target for therapeutic or vaccine-mediated intervention. However, the mechanics of HCV entry remain poorly understood. Here we describe a novel computational model of viral entry, encompassing the relationship between HCV and the key host receptors CD81 and SR-B1. We conduct experiments to thoroughly quantify the influence of an increase or decrease in receptor availability upon the extent of viral entry. We use these data to build and parameterise a mathematical model, which we then validate by further experiments. Our results are consistent with sequential HCV-receptor interactions, whereby initial interaction between the HCV E2 glycoprotein and SR-B1 facilitates the accumulation CD81 receptors, leading to viral entry. However, we also demonstrate that a small minority of viruses can achieve entry in the absence of SR-B1. Our model estimates the impact of the different obstacles that viruses must surmount to achieve entry; among virus particles attaching to the cell surface, around one third of viruses accumulate sufficient CD81 receptors, of which 4-8% then complete the subsequent steps to achieve productive infection. Furthermore, we make estimates of receptor stoichiometry; in excess of 10 receptors are likely to be required to achieve viral entry. Our model provides a tool to investigate the entry characteristics of HCV variants and outlines a framework for future quantitative studies of the multi-receptor dynamics of HCV entry.
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Affiliation(s)
- Mphatso Kalemera
- Institute of Immunity and Transplantation, Division of Infection and Immunity, University College London, United Kingdom
| | - Dilyana Mincheva
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Joe Grove
- Institute of Immunity and Transplantation, Division of Infection and Immunity, University College London, United Kingdom
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231
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Ananthaswamy N, Fang Q, AlSalmi W, Jain S, Chen Z, Klose T, Sun Y, Liu Y, Mahalingam M, Chand S, Tovanabutra S, Robb ML, Rossmann MG, Rao VB. A sequestered fusion peptide in the structure of an HIV-1 transmitted founder envelope trimer. Nat Commun 2019; 10:873. [PMID: 30787293 PMCID: PMC6382815 DOI: 10.1038/s41467-019-08825-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 02/01/2019] [Indexed: 12/23/2022] Open
Abstract
The envelope protein of human immunodeficiency virus-1 (HIV-1) and its fusion peptide are essential for cell entry and vaccine design. Here, we describe the 3.9-Å resolution structure of an envelope protein trimer from a very early transmitted founder virus (CRF01_AE T/F100) complexed with Fab from the broadly neutralizing antibody (bNAb) 8ANC195. The overall T/F100 trimer structure is similar to other reported "closed" state prefusion trimer structures. In contrast, the fusion peptide, which is exposed to solvent in reported closed structures, is sequestered (buried) in the hydrophobic core of the T/F100 trimer. A buried conformation has previously been observed in "open" state structures formed after CD4 receptor binding. The T/F100 trimer binds poorly to bNAbs including the fusion peptide-specific bNAbs PGT151 and VRC34.01. The T/F100 structure might represent a prefusion state, intermediate between the closed and open states. These observations are relevant to mechanisms of HIV-1 transmission and vaccine design.
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Affiliation(s)
- Neeti Ananthaswamy
- Department of Biology, The Catholic University of America, Washington, DC, 20064, USA
| | - Qianglin Fang
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Wadad AlSalmi
- Department of Biology, The Catholic University of America, Washington, DC, 20064, USA
| | - Swati Jain
- Department of Biology, The Catholic University of America, Washington, DC, 20064, USA
| | - Zhenguo Chen
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA.,The Fifth People's Hospital of Shanghai & Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, People's Republic of China
| | - Thomas Klose
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Yingyuan Sun
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Yue Liu
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Marthandan Mahalingam
- Department of Biology, The Catholic University of America, Washington, DC, 20064, USA
| | - Subhash Chand
- Department of Biology, The Catholic University of America, Washington, DC, 20064, USA
| | - Sodsai Tovanabutra
- U.S. Military HIV Research Program, Henry M. Jackson Foundation for the Advancement of Military Medicine, Silver Spring, MD, 20910, USA
| | - Merlin L Robb
- U.S. Military HIV Research Program, Henry M. Jackson Foundation for the Advancement of Military Medicine, Silver Spring, MD, 20910, USA
| | - Michael G Rossmann
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA.
| | - Venigalla B Rao
- Department of Biology, The Catholic University of America, Washington, DC, 20064, USA.
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232
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Dingens AS, Arenz D, Weight H, Overbaugh J, Bloom JD. An Antigenic Atlas of HIV-1 Escape from Broadly Neutralizing Antibodies Distinguishes Functional and Structural Epitopes. Immunity 2019; 50:520-532.e3. [PMID: 30709739 PMCID: PMC6435357 DOI: 10.1016/j.immuni.2018.12.017] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/16/2018] [Accepted: 12/14/2018] [Indexed: 11/18/2022]
Abstract
Anti-HIV broadly neutralizing antibodies (bnAbs) have revealed vaccine targets on the virus's envelope (Env) protein and are themselves promising immunotherapies. The efficacy of bnAb-based therapies and vaccines depends in part on how readily the virus can escape neutralization. Although structural studies can define contacts between bnAbs and Env, only functional studies can define mutations that confer escape. Here, we mapped how all possible single amino acid mutations in Env affect neutralization of HIV by nine bnAbs targeting five epitopes. For most bnAbs, mutations at only a small fraction of structurally defined contact sites mediated escape, and most escape occurred at sites near, but not in direct contact with, the antibody. The Env mutations selected by two pooled bnAbs were similar to those expected from the combination of the bnAbs's independent action. Overall, our mutation-level antigenic atlas provides a comprehensive dataset for understanding viral immune escape and refining therapies and vaccines.
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Affiliation(s)
- Adam S Dingens
- Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Molecular & Cellular Biology PhD Program, University of Washington, Seattle, WA 98195, USA; Division of Human Biology and Epidemiology Program, Seattle, WA 98109, USA
| | - Dana Arenz
- Division of Human Biology and Epidemiology Program, Seattle, WA 98109, USA
| | - Haidyn Weight
- Division of Human Biology and Epidemiology Program, Seattle, WA 98109, USA
| | - Julie Overbaugh
- Division of Human Biology and Epidemiology Program, Seattle, WA 98109, USA.
| | - Jesse D Bloom
- Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Howard Hughes Medical Institute, Seattle, WA 98109, USA.
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233
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Abstract
Purpose of review HIV-1 isolates are often classified on the basis of neutralization ‘tier’ phenotype. Tier classification has important implications for the monitoring and interpretation of vaccine-elicited neutralizing antibody responses. The molecular basis that distinguishes the multiple neutralization phenotypes of HIV-1 has been unclear. We present a model based on the dynamic nature of the HIV-1 envelope glycoproteins and its impact on epitope exposure. We also describe a new approach for ranking HIV-1 vaccine-elicited neutralizing antibody responses. Recent findings The unliganded trimeric HIV-1 envelope glycoprotein spike spontaneously transitions through at least three conformations. Neutralization tier phenotypes correspond to the frequency by which the trimer exists in a closed (tiers 2 and 3), open (tier 1A), or intermediate (tier 1B) conformation. An increasing number of epitopes become exposed as the trimer opens, making the virus more sensitive to neutralization by certain antibodies. The closed conformation is stabilized by many broadly neutralizing antibodies. Summary The tier 2 neutralization phenotype is typical of most circulating strains and is associated with a predominantly closed Env trimer configuration that is a high priority to target with vaccines. Assays with tier 1A viruses should be interpreted with caution and with the understanding that they detect many antibody specificities that do not neutralize tier 2 viruses and do not protect against HIV-1 infection.
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A Coreceptor-Mimetic Peptide Enhances the Potency of V3-Glycan Antibodies. J Virol 2019; 93:JVI.01653-18. [PMID: 30541842 DOI: 10.1128/jvi.01653-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 12/02/2018] [Indexed: 12/23/2022] Open
Abstract
Broadly neutralizing antibodies (bNAbs) target five major epitopes on the HIV-1 envelope glycoprotein (Env). The most potent bNAbs have median half-maximal inhibitory concentration (IC50) values in the nanomolar range, and the broadest bNAbs neutralize up to 98% of HIV-1 strains. The engineered HIV-1 entry inhibitor eCD4-Ig has greater breadth than bNAbs and similar potency. eCD4-Ig is markedly more potent than CD4-Ig due to its C-terminal coreceptor-mimetic peptide. Here we investigated whether the coreceptor-mimetic peptide mim6 improved the potency of bNAbs with different epitopes. We observed that when mim6 was appended to the C terminus of the heavy chains of bNAbs, this sulfopeptide improved the potency of all classes of bNAbs against HIV-1 isolates that are sensitive to neutralization by the sulfopeptide alone. However, mim6 did not significantly enhance neutralization of other isolates when appended to most classes of bNAbs, with one exception. Specifically, mim6 improved the potency of bNAbs of the V3-glycan class, including PGT121, PGT122, PGT128, and 10-1074, by an average of 2-fold for all HIV-1 isolates assayed. Despite this difference, 10-1074 does not induce exposure of the coreceptor-binding site, and addition of mim6 to 10-1074 did not promote shedding of the gp120 subunit of Env. Mixtures of 10-1074 and an Fc domain fused to mim6 neutralized less efficiently than a 10-1074/mim6 fusion, indicating that mim6 enhances the avidity of this fusion. Our data show that mim6 can consistently improve the potency of V3-glycan antibodies and suggest that these antibodies bind in an orientation that facilitates mim6 association with Env.IMPORTANCE HIV-1 requires both the cellular receptor CD4 and a tyrosine-sulfated coreceptor to infect its target cells. CD4-Ig is a fusion of the HIV-1-binding domains of CD4 with an antibody Fc domain. Previous studies have demonstrated that the potency of CD4-Ig is markedly increased by appending a coreceptor-mimetic sulfopeptide to its C terminus. We investigated whether this coreceptor-mimetic peptide improves the potency of broadly neutralizing antibodies (bNAbs) targeting five major epitopes on the HIV-1 envelope glycoprotein (Env). We observed that inclusion of the sulfopeptide dramatically improved the potency of all bNAb classes against isolates with more-open Env structures, typically those that utilize the coreceptor CXCR4. In contrast, the sulfopeptide improved only V3-glycan antibodies when neutralizing primary isolates, on average by 2-fold. These studies improve the potency of one class of bNAbs, show that coreceptor-mimetic sulfopeptides enhance neutralization through distinct mechanisms, and provide insight for the design of novel multispecific entry inhibitors.
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235
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Kumar S, Sarkar A, Pugach P, Sanders RW, Moore JP, Ward AB, Wilson IA. Capturing the inherent structural dynamics of the HIV-1 envelope glycoprotein fusion peptide. Nat Commun 2019; 10:763. [PMID: 30770829 PMCID: PMC6377653 DOI: 10.1038/s41467-019-08738-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 01/25/2019] [Indexed: 02/04/2023] Open
Abstract
The N-terminal fusion peptide (FP) of the human immunodeficiency virus (HIV)-1 envelope glycoprotein (Env) gp41 subunit plays a critical role in cell entry. However, capturing the structural flexibility in the unbound FP is challenging in the native Env trimer. Here, FP conformational isomerism is observed in two crystal structures of a soluble clade B transmitted/founder virus B41 SOSIP.664 Env with broadly neutralizing antibodies (bNAbs) PGT124 and 35O22 to aid in crystallization and that are not specific for binding to the FP. Large rearrangements in the FP and fusion peptide proximal region occur around M530, which remains anchored in the tryptophan clasp (gp41 W623, W628, W631) in the B41 Env prefusion state. Further, we redesigned the FP at position 518 to reinstate the bNAb VRC34.01 epitope. These findings provide further structural evidence for the dynamic nature of the FP and how a bNAb epitope can be restored during vaccine design. The fusion peptide (FP) of HIV envelope (Env) is critical in the cell entry process. Here, Kumar et al. present crystal structures of B41 SOSIP.664 Env trimer and show the dynamic nature of the FP and proximal region, which likely relates to conformational rearrangements required for membrane fusion.
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Affiliation(s)
- Sonu Kumar
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA.,IAVI Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA, 92037, USA.,Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Anita Sarkar
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA.,IAVI Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA, 92037, USA.,Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Pavel Pugach
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY 10065, USA
| | - Rogier W Sanders
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY 10065, USA.,Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - John P Moore
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY 10065, USA
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA.,IAVI Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA, 92037, USA.,Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA. .,IAVI Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA, 92037, USA. .,Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, CA, 92037, USA. .,Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA.
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236
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Abuharfeil NM, Yaseen MM, Alsheyab FM. Harnessing Antibody-Dependent Cellular Cytotoxicity To Control HIV-1 Infection. ACS Infect Dis 2019; 5:158-176. [PMID: 30525453 DOI: 10.1021/acsinfecdis.8b00167] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Passive administration of broadly neutralizing anti-human immunodeficiency virus type 1 (HIV-1) antibodies (bNAbs) has been recently suggested as a promising alternative therapeutic approach for HIV-1 infection. Although the success behind the studies that used this approach has been attributed to the potency and neutralization breadth of anti-HIV-1 antibodies, several lines of evidence support the idea that specific antibody-dependent effector functions, particularly antibody-dependent cellular cytotoxicity (ADCC), play a critical role in controlling HIV-1 infection. In this review, we showed that there is a direct association between the activation of ADCC and better clinical outcomes. This, in turn, suggests that ADCC could be harnessed to control HIV-1 infection. To this end, we addressed the passive administration of bNAbs capable of selectively activating ADCC responses to HIV-1 patients. Finally, we summarized the potential barriers that may impede the optimal activation of ADCC during HIV-1 infection and provided strategic solutions to overcome these barriers.
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Affiliation(s)
- Nizar Mohammad Abuharfeil
- Department of Applied Biological Sciences, College of Science and Arts, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Mahmoud Mohammad Yaseen
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid 22110. Jordan
| | - Fawzi M. Alsheyab
- Department of Applied Biological Sciences, College of Science and Arts, Jordan University of Science and Technology, Irbid 22110, Jordan
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237
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Turner HL, Pallesen J, Lang S, Bangaru S, Urata S, Li S, Cottrell CA, Bowman CA, Crowe JE, Wilson IA, Ward AB. Potent anti-influenza H7 human monoclonal antibody induces separation of hemagglutinin receptor-binding head domains. PLoS Biol 2019; 17:e3000139. [PMID: 30716060 PMCID: PMC6375650 DOI: 10.1371/journal.pbio.3000139] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 02/14/2019] [Accepted: 01/18/2019] [Indexed: 01/02/2023] Open
Abstract
Seasonal influenza virus infections can cause significant morbidity and mortality, but the threat from the emergence of a new pandemic influenza strain might have potentially even more devastating consequences. As such, there is intense interest in isolating and characterizing potent neutralizing antibodies that target the hemagglutinin (HA) viral surface glycoprotein. Here, we use cryo-electron microscopy (cryoEM) to decipher the mechanism of action of a potent HA head-directed monoclonal antibody (mAb) bound to an influenza H7 HA. The epitope of the antibody is not solvent accessible in the compact, prefusion conformation that typifies all HA structures to date. Instead, the antibody binds between HA head protomers to an epitope that must be partly or transiently exposed in the prefusion conformation. The "breathing" of the HA protomers is implied by the exposure of this epitope, which is consistent with metastability of class I fusion proteins. This structure likely therefore represents an early structural intermediate in the viral fusion process. Understanding the extent of transient exposure of conserved neutralizing epitopes also may lead to new opportunities to combat influenza that have not been appreciated previously.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Neutralizing/chemistry
- Antibodies, Neutralizing/genetics
- Antibodies, Neutralizing/metabolism
- Antibody Specificity
- Baculoviridae/genetics
- Baculoviridae/metabolism
- Binding Sites
- Cloning, Molecular
- Cryoelectron Microscopy
- Gene Expression
- Hemagglutinin Glycoproteins, Influenza Virus/chemistry
- Hemagglutinin Glycoproteins, Influenza Virus/genetics
- Hemagglutinin Glycoproteins, Influenza Virus/immunology
- Hydrogen Bonding
- Immunoglobulin Fab Fragments/chemistry
- Immunoglobulin Fab Fragments/genetics
- Immunoglobulin Fab Fragments/metabolism
- Influenza A virus/chemistry
- Influenza A virus/genetics
- Influenza A virus/immunology
- Molecular Docking Simulation
- Protein Binding
- Protein Conformation, alpha-Helical
- Protein Conformation, beta-Strand
- Protein Interaction Domains and Motifs
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/immunology
- Sequence Alignment
- Sequence Homology, Amino Acid
- Sf9 Cells
- Spodoptera
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Affiliation(s)
- Hannah L. Turner
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Jesper Pallesen
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Shanshan Lang
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Sandhya Bangaru
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Sarah Urata
- Department of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Sheng Li
- Department of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Christopher A. Cottrell
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Charles A. Bowman
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - James E. Crowe
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Ian A. Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, United States of America
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Andrew B. Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, United States of America
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238
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Anand SP, Prévost J, Baril S, Richard J, Medjahed H, Chapleau JP, Tolbert WD, Kirk S, Smith AB, Wines BD, Kent SJ, Hogarth PM, Parsons MS, Pazgier M, Finzi A. Two Families of Env Antibodies Efficiently Engage Fc-Gamma Receptors and Eliminate HIV-1-Infected Cells. J Virol 2019; 93:e01823-18. [PMID: 30429344 PMCID: PMC6340017 DOI: 10.1128/jvi.01823-18] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 11/07/2018] [Indexed: 12/17/2022] Open
Abstract
HIV-1 conceals epitopes of its envelope glycoproteins (Env) recognized by antibody (Ab)-dependent cellular cytotoxicity (ADCC)-mediating antibodies. These Abs, including anti-coreceptor binding site (CoRBS) and anti-cluster A antibodies, preferentially recognize Env in its "open" conformation. The binding of anti-CoRBS Abs has been shown to induce conformational changes that further open Env, allowing interaction of anti-cluster A antibodies. We explored the possibility that CoRBS Abs synergize with anti-cluster A Abs to engage Fc-gamma receptors to mediate ADCC. We found that binding of anti-CoRBS and anti-cluster A Abs to the same gp120 is required for interaction with soluble dimeric FcγRIIIa in enzyme-linked immunosorbent assays (ELISAs). We also found that Fc regions of both Abs are required to optimally engage FcγRIIIa and mediate robust ADCC. Taken together, our results indicate that these two families of Abs act together in a sequential and synergistic fashion to promote FcγRIIIa engagement and ADCC.IMPORTANCE The "open" CD4-bound conformation of HIV-1 envelope glycoproteins is the primary target of antibody-dependent cellular cytotoxicity (ADCC)-mediating antibodies present in HIV-positive (HIV+) sera, such as anti-coreceptor binding site and anti-cluster A antibodies. Here we report that the binding of these two families of antibodies is required to engage FcγRIIIa and mediate ADCC.
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Affiliation(s)
- Sai Priya Anand
- Centre de Recherche du CHUM, Montreal, QC, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, QC, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
| | - Sophie Baril
- Centre de Recherche du CHUM, Montreal, QC, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
| | - Jonathan Richard
- Centre de Recherche du CHUM, Montreal, QC, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
| | | | - Jean-Philippe Chapleau
- Centre de Recherche du CHUM, Montreal, QC, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
| | - William D Tolbert
- Infectious Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Sharon Kirk
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Amos B Smith
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Bruce D Wines
- Immune Therapies Group Burnet Institute, Melbourne, Victoria, Australia
- Department of Clinical Pathology, University of Melbourne, Melbourne, Victoria, Australia
- Department of Immunology and Pathology, Monash University, Melbourne, Victoria, Australia
| | - Stephen J Kent
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - P Mark Hogarth
- Immune Therapies Group Burnet Institute, Melbourne, Victoria, Australia
- Department of Clinical Pathology, University of Melbourne, Melbourne, Victoria, Australia
- Department of Immunology and Pathology, Monash University, Melbourne, Victoria, Australia
| | - Matthew S Parsons
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Marzena Pazgier
- Infectious Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, QC, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
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239
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Rey FA, Lok SM. Common Features of Enveloped Viruses and Implications for Immunogen Design for Next-Generation Vaccines. Cell 2019. [PMID: 29522750 PMCID: PMC7112304 DOI: 10.1016/j.cell.2018.02.054] [Citation(s) in RCA: 174] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Enveloped viruses enter cells by inducing fusion of viral and cellular membranes, a process catalyzed by a specialized membrane-fusion protein expressed on their surface. This review focuses on recent structural studies of viral fusion proteins with an emphasis on their metastable prefusion form and on interactions with neutralizing antibodies. The fusion glycoproteins have been difficult to study because they are present in a labile, metastable form at the surface of infectious virions. Such metastability is a functional requirement, allowing these proteins to refold into a lower energy conformation while transferring the difference in energy to catalyze the membrane fusion reaction. Structural studies have shown that stable immunogens presenting the same antigenic sites as the labile wild-type proteins efficiently elicit potently neutralizing antibodies, providing a framework with which to engineer the antigens for stability, as well as identifying key vulnerability sites that can be used in next-generation subunit vaccine design.
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Affiliation(s)
- Felix A Rey
- Institut Pasteur, Structural Virology Unit, CNRS UMR3569, 25-28 rue du Dr. Roux, 75015 Paris, France.
| | - Shee-Mei Lok
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore AND Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore.
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240
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Doi N, Yokoyama M, Koma T, Kotani O, Sato H, Adachi A, Nomaguchi M. Concomitant Enhancement of HIV-1 Replication Potential and Neutralization-Resistance in Concert With Three Adaptive Mutations in Env V1/C2/C4 Domains. Front Microbiol 2019; 10:2. [PMID: 30705669 PMCID: PMC6344430 DOI: 10.3389/fmicb.2019.00002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 01/04/2019] [Indexed: 12/23/2022] Open
Abstract
HIV-1 Env protein functions in the entry process and is the target of neutralizing antibodies. Its intrinsically high mutation rate is certainly one of driving forces for persistence/survival in hosts. For optimal replication in various environments, HIV-1 Env must continue to adapt and evolve through balancing sometimes incompatible function, replication fitness, and neutralization sensitivity. We have previously reported that adapted viruses emerge in repeated and prolonged cultures of cells originally infected with a macaque-tropic HIV-1NL4-3 derivative. We have also shown that the adapted viral clones exhibit enhanced growth potentials both in macaque PBMCs and individuals, and that three single-amino acid mutations are present in their Env V1/C2/C4 domains. In this study, we investigated how lab-adapted and highly neutralization-sensitive HIV-1NL4-3 adapts its Env to macaque cells with strongly replication-restrictive nature for HIV-1. While a single and two mutations gave a significantly enhanced replication phenotype in a macaque cell line and also in human cell lines that stably express either human CD4 or macaque CD4, the virus simultaneously carrying the three adaptive mutations always grew best. Entry kinetics of parental and triple mutant viruses were similar, whereas the mutant was significantly more readily inhibited for its infectivity by soluble CD4 than parental virus. Furthermore, molecular dynamics simulations of the Env ectodomain (gp120 and gp41 ectodomain) bound with CD4 suggest that the three mutations increase binding affinity of Env for CD4 in solution. Thus, it is quite likely that the affinity for CD4 of the mutant Env is enhanced relative to the parental Env. Neutralization sensitivity of the triple mutant to CD4 binding site antibodies was not significantly different from that of parental virus, whereas the mutant exhibited a considerably higher resistance against neutralization by a CD4-induced epitope antibody and Env trimer-targeting V1/V2 antibodies. These results suggest that the three adaptive mutations cooperatively promote viral growth via increased CD4 affinity, and also that they enhance viral resistance to several neutralization antibodies by changing the Env-trimer conformation. In total, we have verified here an HIV-1 adaptation pathway in host cells and individuals involving Env derived from a lab-adapted and highly neutralization-sensitive clone.
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Affiliation(s)
- Naoya Doi
- Department of Microbiology, Tokushima University Graduate School of Medical Sciences, Tokushima, Japan
| | - Masaru Yokoyama
- Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Takaaki Koma
- Department of Microbiology, Tokushima University Graduate School of Medical Sciences, Tokushima, Japan
| | - Osamu Kotani
- Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Hironori Sato
- Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Akio Adachi
- Department of Microbiology, Kansai Medical University, Osaka, Japan
| | - Masako Nomaguchi
- Department of Microbiology, Tokushima University Graduate School of Medical Sciences, Tokushima, Japan
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241
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Conformational Differences between Functional Human Immunodeficiency Virus Envelope Glycoprotein Trimers and Stabilized Soluble Trimers. J Virol 2019; 93:JVI.01709-18. [PMID: 30429345 DOI: 10.1128/jvi.01709-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 11/07/2018] [Indexed: 01/11/2023] Open
Abstract
Binding to the receptor CD4 triggers entry-related conformational changes in the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) trimer, (gp120/gp41)3 Soluble versions of HIV-1 Env trimers (sgp140 SOSIP.664) stabilized by a gp120-gp41 disulfide bond and a change (I559P) in gp41 have been structurally characterized. Here, we use cross-linking/mass spectrometry to evaluate the conformations of functional membrane Env and sgp140 SOSIP.664. Differences were detected in the gp120 trimer association domain and C terminus and in the gp41 heptad repeat 1 (HR1) region. Whereas the membrane Env trimer exposes the gp41 HR1 coiled coil only after CD4 binding, the sgp140 SOSIP.664 HR1 coiled coil was accessible to the gp41 HR2 peptide even in the absence of CD4. Our results delineate differences in both gp120 and gp41 subunits between functional membrane Env and the sgp140 SOSIP.664 trimer and provide distance constraints that can assist validation of candidate structural models of the native HIV-1 Env trimer.IMPORTANCE HIV-1 envelope glycoprotein spikes mediate the entry of the virus into host cells and are a major target for vaccine-induced antibodies. Soluble forms of the envelope glycoproteins that are stable and easily produced have been characterized extensively and are being considered as vaccines. Here, we present evidence that these stabilized soluble envelope glycoproteins differ in multiple respects from the natural HIV-1 envelope glycoproteins. By pinpointing these differences, our results can guide the improvement of envelope glycoprotein preparations to achieve greater similarity to the viral envelope glycoprotein spike, potentially increasing their effectiveness as a vaccine.
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242
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Zhang P, Gorman J, Geng H, Liu Q, Lin Y, Tsybovsky Y, Go EP, Dey B, Andine T, Kwon A, Patel M, Gururani D, Uddin F, Guzzo C, Cimbro R, Miao H, McKee K, Chuang GY, Martin L, Sironi F, Malnati MS, Desaire H, Berger EA, Mascola JR, Dolan MA, Kwong PD, Lusso P. Interdomain Stabilization Impairs CD4 Binding and Improves Immunogenicity of the HIV-1 Envelope Trimer. Cell Host Microbe 2019; 23:832-844.e6. [PMID: 29902444 DOI: 10.1016/j.chom.2018.05.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 04/04/2018] [Accepted: 05/02/2018] [Indexed: 01/29/2023]
Abstract
The HIV-1 envelope (Env) spike is a trimer of gp120/gp41 heterodimers that mediates viral entry. Binding to CD4 on the host cell membrane is the first essential step for infection but disrupts the native antigenic state of Env, posing a key obstacle to vaccine development. We locked the HIV-1 Env trimer in a pre-fusion configuration, resulting in impaired CD4 binding and enhanced binding to broadly neutralizing antibodies. This design was achieved via structure-guided introduction of neo-disulfide bonds bridging the gp120 inner and outer domains and was successfully applied to soluble trimers and native gp160 from different HIV-1 clades. Crystallization illustrated the structural basis for CD4-binding impairment. Immunization of rabbits with locked trimers from two different clades elicited neutralizing antibodies against tier-2 viruses with a repaired glycan shield regardless of treatment with a functional CD4 mimic. Thus, interdomain stabilization provides a widely applicable template for the design of Env-based HIV-1 vaccines.
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Affiliation(s)
- Peng Zhang
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Jason Gorman
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Hui Geng
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Qingbo Liu
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Yin Lin
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Yaroslav Tsybovsky
- Electron Microscopy Laboratory, Cancer Research Technology Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, MD 21701, USA
| | - Eden P Go
- Department of Chemistry, University of Kansas, Lawrence, KS 66047, USA
| | - Barna Dey
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Tsion Andine
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Alice Kwon
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Mit Patel
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Deepali Gururani
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Ferzan Uddin
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Christina Guzzo
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Raffaello Cimbro
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Huiyi Miao
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Krisha McKee
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Gwo-Yu Chuang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Loïc Martin
- CEA, Joliot, Service d'Ingénierie Moléculaire des Protéines, 91191 Gif-sur-Yvette, France
| | - Francesca Sironi
- Department of Biological and Technological Research, San Raffaele Scientific Institute, Milan 20122, Italy
| | - Mauro S Malnati
- Department of Biological and Technological Research, San Raffaele Scientific Institute, Milan 20122, Italy
| | - Heather Desaire
- Department of Chemistry, University of Kansas, Lawrence, KS 66047, USA
| | - Edward A Berger
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - John R Mascola
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Michael A Dolan
- Bioinformatics and Computational Biosciences Branch, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Paolo Lusso
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA.
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243
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Ivan B, Sun Z, Subbaraman H, Friedrich N, Trkola A. CD4 occupancy triggers sequential pre-fusion conformational states of the HIV-1 envelope trimer with relevance for broadly neutralizing antibody activity. PLoS Biol 2019; 17:e3000114. [PMID: 30650070 PMCID: PMC6351000 DOI: 10.1371/journal.pbio.3000114] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 01/29/2019] [Accepted: 01/04/2019] [Indexed: 12/18/2022] Open
Abstract
During the entry process, the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) trimer undergoes a sequence of conformational changes triggered by both CD4 and coreceptor engagement. Resolving the conformation of these transient entry intermediates has proven challenging. Here, we fine-mapped the antigenicity of entry intermediates induced by increasing CD4 engagement of cell surface–expressed Env. Escalating CD4 triggering led to the sequential adoption of different pre-fusion conformational states of the Env trimer, up to the pre-hairpin conformation, that we assessed for antibody epitope presentation. Maximal accessibility of the coreceptor binding site was detected below Env saturation by CD4. Exposure of the fusion peptide and heptad repeat 1 (HR1) required higher CD4 occupancy. Analyzing the diverse antigenic states of the Env trimer, we obtained key insights into the transitions in epitope accessibility of broadly neutralizing antibodies (bnAbs). Several bnAbs preferentially bound CD4-triggered Env, indicating a potential capacity to neutralize both pre- and post-CD4 engagement, which needs to be explored. Assessing binding and neutralization activity of bnAbs, we confirm antibody dissociation rates as a driver of incomplete neutralization. Collectively, our findings highlight a need to resolve Env conformations that are neutralization-relevant to provide guidance for immunogen development. Comprehensive mapping of conformational stages adopted by the HIV‐1 envelope glycoprotein trimer during entry into the cell reveals the preference of broadly neutralizing antibodies for distinct pre-fusion states of the trimer. The trimeric human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) mediates HIV-1 entry into its target cells. Entry is initiated by sequential triggering of Env upon interaction with its primary receptor CD4 and a coreceptor on target cells. The ensuing structural rearrangements of the Env trimer bring the viral membrane in close vicinity of the cellular membrane, enabling fusion. Resolving the structural differences between the consecutive conformations Env adopts during the entry process is of high interest, as different antigenic domains are exposed, which may affect the capacity of neutralizing antibodies to bind to Env and inhibit entry. Here, we compared the conformation of unliganded closed Env with the transitional CD4-bound Env forms by studying the antigenicity of cell surface–expressed Env with and without CD4 triggering. We show that incremental triggering by soluble CD4 allows the capture of the full continuum of conformational changes, including events that follow coreceptor interaction. Thus, the setup we introduce here turns a simple binding assay into a powerful tool to study transitional conformation changes in HIV-1 Env. Analyzing the capacity of Env-reactive antibodies to recognize the diverse Env stages, our study reveals novel aspects of the binding preferences of neutralizing antibodies that affect their inhibitory activity.
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Affiliation(s)
- Branislav Ivan
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Zhaozhi Sun
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Harini Subbaraman
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Nikolas Friedrich
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Alexandra Trkola
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
- * E-mail:
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244
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Wang L, Izadmehr S, Kamau E, Kong XP, Chen BK. Sequential trafficking of Env and Gag to HIV-1 T cell virological synapses revealed by live imaging. Retrovirology 2019; 16:2. [PMID: 30646921 PMCID: PMC6334456 DOI: 10.1186/s12977-019-0464-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 01/07/2019] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND HIV infection is enhanced by cell adhesions that form between infected and uninfected T cells called virological synapses (VS). VS are initiated by an interaction between Env and CD4 on cell surfaces and result in the recruitment of virus assembly to the site of cell-cell contact. However, the recruitment of Env to the VS and its relationship to Gag recruitment is not well defined. RESULTS To study the trafficking of HIV-1 Env through the VS, we constructed a molecular clone of HIV carrying a green fluorescent protein-Env fusion protein called, HIV Env-isfGFP-∆V1V2. The Env-isfGFP-∆V1V2 fusion protein does not produce virus particles on its own, but can be rescued by cotransfection with full-length HIV constructs and produce virus particles that package the fluorescent Env. These rescued fluorescent Env can participate in VS formation and can be used to directly image CD4-dependent Env transfer across VS from donor to target cells. The movements of fluorescently tagged Gag and Env to the VS and transfer into target cells can be also tracked through live imaging. Time lapse live imaging reveals evidence of limited Env accumulation at the site of cell-cell contact shortly after cell adhesion, followed by Gag re-distribution to contact area. Both Gag and Env can be recruited to form button-like spots characteristic of VS. CONCLUSIONS Env and Gag are recruited to the VS in a coordinated temporal sequence and subsequently transfer together across the synapse into the target cell. Env accumulations, when observed, are earlier than Gag re-distribution to the contact area during formation of VS.
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Affiliation(s)
- Lili Wang
- 0000 0001 0670 2351grid.59734.3cDepartment of Medicine, Division of Infectious Diseases, Immunology Institute, Mount Sinai School of Medicine, New York, NY 10029 USA
| | - Sudeh Izadmehr
- 0000 0001 0670 2351grid.59734.3cDepartment of Medicine, Division of Infectious Diseases, Immunology Institute, Mount Sinai School of Medicine, New York, NY 10029 USA
| | - Edwin Kamau
- 0000 0004 1936 8753grid.137628.9Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, New York, NY 10016 USA
| | - Xiang-Peng Kong
- 0000 0004 1936 8753grid.137628.9Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, New York, NY 10016 USA
| | - Benjamin K. Chen
- 0000 0001 0670 2351grid.59734.3cDepartment of Medicine, Division of Infectious Diseases, Immunology Institute, Mount Sinai School of Medicine, New York, NY 10029 USA
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245
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Li Y, Deng L, Yang LQ, Sang P, Liu SQ. Effects of CD4 Binding on Conformational Dynamics, Molecular Motions, and Thermodynamics of HIV-1 gp120. Int J Mol Sci 2019; 20:E260. [PMID: 30634692 PMCID: PMC6359530 DOI: 10.3390/ijms20020260] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 12/19/2018] [Accepted: 12/19/2018] [Indexed: 12/04/2022] Open
Abstract
Human immunodeficiency virus type-1 (HIV-1) infection is triggered by its envelope (Env) glycoprotein gp120 binding to the host-cell receptor CD4. Although structures of Env/gp120 in the liganded state are known, detailed information about dynamics of the liganded gp120 has remained elusive. Two structural models, the CD4-free gp120 and the gp120-CD4 complex, were subjected to µs-scale multiple-replica molecular dynamics (MD) simulations to probe the effects of CD4 binding on the conformational dynamics, molecular motions, and thermodynamics of gp120. Comparative analyses of MD trajectories in terms of structural deviation and conformational flexibility reveal that CD4 binding effectively suppresses the overall conformational fluctuations of gp120. Despite the largest fluctuation amplitude of the V1/V2 region in both forms of gp120, the presence of CD4 prevents it from approaching the gp120 core. Comparison of the constructed free energy landscapes (FELs) shows that CD4 binding reduces the conformational entropy and conformational diversity while enhancing the stability of gp120. Further comparison of the representative structures extracted from free energy basins/minima of FELs reveals that CD4 binding weakens the reorientation ability of V1/V2 and hence hinders gp120 from transitioning out of the liganded state to the unliganded state. Therefore, locking gp120 conformation via restraining V1/V2 reorientation with small molecules seems to be a promising strategy to control HIV-1 infection. Our computer simulation results support the conformational selection mechanism for CD4 binding to gp120 and facilitate the understanding of HIV-1 immune evasion mechanisms.
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Affiliation(s)
- Yi Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan & School of Life Sciences, Yunnan University, Kunming 650091, China.
- College of Mathematics and Computer, Dali University, Dali 671003, China.
| | - Lei Deng
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan & School of Life Sciences, Yunnan University, Kunming 650091, China.
| | - Li-Quan Yang
- College of Agriculture and Biological Science, Dali University, Dali 671003, China.
| | - Peng Sang
- College of Agriculture and Biological Science, Dali University, Dali 671003, China.
| | - Shu-Qun Liu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan & School of Life Sciences, Yunnan University, Kunming 650091, China.
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246
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Carravilla P, Chojnacki J, Rujas E, Insausti S, Largo E, Waithe D, Apellaniz B, Sicard T, Julien JP, Eggeling C, Nieva JL. Molecular recognition of the native HIV-1 MPER revealed by STED microscopy of single virions. Nat Commun 2019; 10:78. [PMID: 30622256 PMCID: PMC6325134 DOI: 10.1038/s41467-018-07962-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 12/07/2018] [Indexed: 11/09/2022] Open
Abstract
Antibodies against the Membrane-Proximal External Region (MPER) of the Env gp41 subunit neutralize HIV-1 with exceptional breadth and potency. Due to the lack of knowledge on the MPER native structure and accessibility, different and exclusive models have been proposed for the molecular mechanism of MPER recognition by broadly neutralizing antibodies. Here, accessibility of antibodies to the native Env MPER on single virions has been addressed through STED microscopy. STED imaging of fluorescently labeled Fabs reveals a common pattern of native Env recognition for HIV-1 antibodies targeting MPER or the surface subunit gp120. In the case of anti-MPER antibodies, the process evolves with extra contribution of interactions with the viral lipid membrane to binding specificity. Our data provide biophysical insights into the recognition of the potent and broadly neutralizing MPER epitope on HIV virions, and as such is of importance for the design of therapeutic interventions.
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Affiliation(s)
- Pablo Carravilla
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080, Bilbao, Spain
| | - Jakub Chojnacki
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Edurne Rujas
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080, Bilbao, Spain
| | - Sara Insausti
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080, Bilbao, Spain
| | - Eneko Largo
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080, Bilbao, Spain
| | - Dominic Waithe
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Beatriz Apellaniz
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080, Bilbao, Spain
| | - Taylor Sicard
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, ON, M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Jean-Philippe Julien
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, ON, M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
- Department of Immunology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Christian Eggeling
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK.
- Institute of Applied Optics Friedrich-Schiller-University Jena, Max-Wien Platz 4, 07743, Jena, Germany.
- Leibniz Institute of Photonic Technology e.V., Albert-Einstein-Straße 9, 07745, Jena, Germany.
| | - José L Nieva
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080, Bilbao, Spain.
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247
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Structural Constraints at the Trimer Apex Stabilize the HIV-1 Envelope in a Closed, Antibody-Protected Conformation. mBio 2018; 9:mBio.00955-18. [PMID: 30538178 PMCID: PMC6299476 DOI: 10.1128/mbio.00955-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The extraordinary ability of human immunodeficiency virus type 1 (HIV-1) to evade host immunity represents a major obstacle to the development of a protective vaccine. Thus, elucidating the mechanisms whereby HIV-1 protects its external envelope (Env), which is the sole target of virus-neutralizing antibodies, is an essential step toward vaccine design. We identified a key structural element that maintains the HIV-1 Env trimer in a closed, antibody-resistant conformation. A major role is played by two conserved tyrosines at the apex of the Env spike, whose mutation causes a global opening of the trimer structure, exposing multiple concealed targets for neutralizing antibodies. We also found that HIV-infected individuals produce very large amounts of antibodies that neutralize the open Env form; however, the bulk of these antibodies are unable to penetrate the tight defensive shield of the native virus. This work may help to devise new strategies to overcome the viral defensive mechanisms and facilitate the development of an effective HIV-1 vaccine. The human immunodeficiency virus type 1 (HIV-1) envelope (Env) trimer evades antibody recognition by adopting a closed prefusion conformation. Here, we show that two conserved tyrosines (Y173, Y177) within the second variable (V2) loop of the gp120 Env glycoprotein are key regulators of the closed, antibody-protected state of the trimer by establishing intramolecular interaction with the base of the third variable (V3) loop. Mutation of Y177 and/or Y173 to phenylalanine or alanine dramatically altered the susceptibility of diverse HIV-1 strains to neutralization, increasing sensitivity to weakly and nonneutralizing antibodies directed against diverse Env regions, consistent with the adoption of an open trimer configuration. Conversely, potent broadly neutralizing antibodies (bNAbs) against different supersites of HIV-1 vulnerability exhibited reduced potency against V2 loop tyrosine mutants, consistent with their preferential targeting of the closed trimer. Mutation of V3 loop residues predicted to interact with the V2 loop tyrosines yielded a similar neutralization phenotype. Sera from chronically HIV-1-infected patients contained very high titers of antibodies capable of neutralizing V2 loop tyrosine mutants but not wild-type viruses, indicating that the bulk of antibodies produced in infected hosts are unable to penetrate the protective shield of the closed trimer. These results identify the tyrosine-mediated V2-V3 loop complex at the trimer apex as a key structural constraint that facilitates HIV-1 evasion from the bulk of host antibodies.
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248
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van Schooten J, van Gils MJ. HIV-1 immunogens and strategies to drive antibody responses towards neutralization breadth. Retrovirology 2018; 15:74. [PMID: 30477581 PMCID: PMC6260891 DOI: 10.1186/s12977-018-0457-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 11/16/2018] [Indexed: 12/13/2022] Open
Abstract
Despite enormous efforts no HIV-1 vaccine has been developed that elicits broadly neutralizing antibodies (bNAbs) to protect against infection to date. The high antigenic diversity and dense N-linked glycan armor, which covers nearly the entire HIV-1 envelope protein (Env), are major roadblocks for the development of bNAbs by vaccination. In addition, the naive human antibody repertoire features a low frequency of exceptionally long heavy chain complementary determining regions (CDRH3s), which is a typical characteristic that many HIV-1 bNAbs use to penetrate the glycan armor. Native-like Env trimer immunogens can induce potent but strain-specific neutralizing antibody responses in animal models but how to overcome the many obstacles towards the development of bNAbs remains a challenge. Here, we review recent HIV-1 Env immunization studies and discuss strategies to guide strain-specific antibody responses towards neutralization breadth.
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Affiliation(s)
- Jelle van Schooten
- Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Location AMC, Meibergdreef 9, Room K3-105, 1105AZ, Amsterdam, The Netherlands
| | - Marit J van Gils
- Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Location AMC, Meibergdreef 9, Room K3-105, 1105AZ, Amsterdam, The Netherlands.
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249
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Chuang GY, Zhou J, Acharya P, Rawi R, Shen CH, Sheng Z, Zhang B, Zhou T, Bailer RT, Dandey VP, Doria-Rose NA, Louder MK, McKee K, Mascola JR, Shapiro L, Kwong PD. Structural Survey of Broadly Neutralizing Antibodies Targeting the HIV-1 Env Trimer Delineates Epitope Categories and Characteristics of Recognition. Structure 2018; 27:196-206.e6. [PMID: 30471922 DOI: 10.1016/j.str.2018.10.007] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 08/01/2018] [Accepted: 10/10/2018] [Indexed: 01/23/2023]
Abstract
Over the past decade, structures have been determined for broadly neutralizing antibodies that recognize all major exposed surfaces of the prefusion-closed HIV-1-envelope (Env) trimer. To understand this recognition and its implications, we analyzed 206 antibody-HIV-1 Env structures from the Protein Data Bank with resolution suitable to define interaction chemistries and measured antibody neutralization on a 208-strain panel. Those with >25% breadth segregated into almost two dozen classes based on ontogeny and recognition and into six epitope categories based on recognized Env residues. For paratope, the number of protruding loops and level of somatic hypermutation were significantly higher for broad HIV-1 neutralizing antibodies than for a comparison set of non-HIV-1 antibodies (p < 0.0001). For epitope, the number of independent sequence segments was higher (p < 0.0001), as well as the glycan component surface area (p = 0.0005). The unusual characteristics of epitope and paratope delineated here are likely to reflect respectively virus-immune evasion and antibody-recognition solutions that allow effective neutralization of HIV-1.
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Affiliation(s)
- Gwo-Yu Chuang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Jing Zhou
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Priyamvada Acharya
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Reda Rawi
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Chen-Hsiang Shen
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zizhang Sheng
- Department of Biochemistry and Molecular Biophysics & Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10032, USA
| | - Baoshan Zhang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tongqing Zhou
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Robert T Bailer
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Venkata P Dandey
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Nicole A Doria-Rose
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mark K Louder
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Krisha McKee
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - John R Mascola
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lawrence Shapiro
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Department of Biochemistry and Molecular Biophysics & Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10032, USA
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Department of Biochemistry and Molecular Biophysics & Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10032, USA.
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250
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Abstract
: Interactions between the Fc segment of IgG and its receptors (FcγRs) found on cells such as natural killer cells, monocytes, macrophages and neutrophils can potentially mediate antiviral effects in the setting of HIV and related infections. We review the potential role of FcγR interactions in HIV, SIV and SHIV infections, with an emphasis on antibody-dependent cellular cytotoxicity (ADCC). Notably, these viruses employ various strategies, including CD4 down-regulation and BST-2/tetherin antagonism to limit the effect of ADCC. Although correlative data suggest that ADCC participates in both protection and control of established infection, there is little direct evidence in support of either role. Direct evidence does, however, implicate an FcγR-dependent function in augmenting the beneficial in vivo activity of neutralizing antibodies.
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