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Characteristics of HIV-1 env genes from Chinese chronically infected donors with highly broad cross-neutralizing activity. Virology 2020; 551:16-25. [PMID: 33010671 DOI: 10.1016/j.virol.2020.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 08/17/2020] [Accepted: 08/23/2020] [Indexed: 11/24/2022]
Abstract
Knowledge about the special characteristics of HIV-1 envelope (env) glycoproteins in rare individuals developing >90% neutralization breadth in Chinese subtype B' slow progressors may provide insights for vaccine design against local viruses. We performed a cross-sectional analysis on 7 samples. We tested the neutralization breadth and geometric mean ID50 titers (GMTs) of these samples, and divided them into hBCN+ and hBCN- group according to whether their neutralization breadth >90%. We obtained env sequences in these samples through single genome amplification (SGA) assay. By comparing with hBCN-, subtype B chronically infected group (B-SP), and Chinese subtype B group (B-Database), we analyzed the characteristics of the env sequences of hBCN+ group. Longer V1 and V4 regions with more glycosylation sites were found in hBCN+ samples compared to hBCN- samples. Further analysis compared to B-SP and B-Database showed that hBCN+ group exhibited unique extra-long V1 region containing higher proportion of N-glycan sites and additional cysteines.
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2
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Hutchinson JM, Mesa KA, Alexander DL, Yu B, O'Rourke SM, Limoli KL, Wrin T, Deeks SG, Berman PW. Unusual Cysteine Content in V1 Region of gp120 From an Elite Suppressor That Produces Broadly Neutralizing Antibodies. Front Immunol 2019; 10:1021. [PMID: 31156622 PMCID: PMC6530427 DOI: 10.3389/fimmu.2019.01021] [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: 02/12/2019] [Accepted: 04/23/2019] [Indexed: 01/21/2023] Open
Abstract
Although it is now possible to produce recombinant HIV envelope glycoproteins (Envs) with epitopes recognized by the 5–6 major classes of broadly neutralizing antibodies (bNAbs), these have failed to consistently stimulate the formation of bNAbs in immunized animals or humans. In an effort to identify new immunogens better able to elicit bNAbs, we are studying Envs derived from rare individuals who possess bNAbs and are able to control their infection without the need for anti-retroviral drugs (elite supressors or ES), hypothesizing that in at least some people the antibodies may mediate durable virus control. Because virus evolution in people with the ES only phenotype was reported to be limited, we reasoned the Env proteins recovered from these individuals may more closely resemble the Envs that gave rise to bNAbs compared to the highly diverse viruses isolated from normal progressors. Using a phenotypic assay, we screened 25 controllers and identified two for more detailed investigation. In this study, we examined 20 clade B proviral sequences isolated from an African American woman, who had the rare bNAb/ES phenotype. Phylogenetic analysis of proviral envelope sequences demonstrated low genetic diversity. Envelope proteins were unusual in that most possessed two extra cysteines within an elongated V1 region. In this report, we examine the impact of the extra cysteines on the binding to bNAbs, virus infectivity, and sensitivity to neutralization. These data suggest structural motifs in V1 can affect infectivity, and that rare viruses may be prevented from developing escape.
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Affiliation(s)
- Jennie M Hutchinson
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Kathryn A Mesa
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - David L Alexander
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Bin Yu
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Sara M O'Rourke
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Kay L Limoli
- Monogram Biosciences, South San Francisco, CA, United States
| | - Terri Wrin
- Monogram Biosciences, South San Francisco, CA, United States
| | - Steven G Deeks
- Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Phillip W Berman
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA, United States
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3
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de Taeye SW, Go EP, Sliepen K, de la Peña AT, Badal K, Medina-Ramírez M, Lee WH, Desaire H, Wilson IA, Moore JP, Ward AB, Sanders RW. Stabilization of the V2 loop improves the presentation of V2 loop-associated broadly neutralizing antibody epitopes on HIV-1 envelope trimers. J Biol Chem 2019; 294:5616-5631. [PMID: 30728245 PMCID: PMC6462529 DOI: 10.1074/jbc.ra118.005396] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 01/15/2019] [Indexed: 11/16/2022] Open
Abstract
A successful HIV-1 vaccine will likely need to elicit broadly neutralizing antibodies (bNAbs) that target the envelope glycoprotein (Env) spike on the virus. Native-like recombinant Env trimers of the SOSIP design now serve as a platform for achieving this challenging goal. However, SOSIP trimers usually do not bind efficiently to the inferred germline precursors of bNAbs (gl-bNAbs). We hypothesized that the inherent flexibilities of the V1 and V2 variable loops in the Env trimer contribute to the poor recognition of gl-bNAb epitopes at the trimer apex that extensively involve V2 residues. To reduce local V2 flexibility and improve the binding of V2-dependent bNAbs and gl-bNAbs, we designed BG505 SOSIP.664 trimer variants containing newly created disulfide bonds intended to stabilize the V2 loop in an optimally antigenic configuration. The first variant, I184C/E190C, contained a new disulfide bond within the V2 loop, whereas the second variant, E153C/R178C, had a new disulfide bond that cross-linked V2 and V1. The resulting engineered native-like trimer variants were both more reactive with and were neutralized by V2 bNAbs and gl-bNAbs, a finding that may be valuable in the design of germline targeting and boosting trimer immunogens to create an antigenic conformation optimal for HIV vaccine development.
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Affiliation(s)
- Steven W de Taeye
- From the Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam, 1105 AZ, The Netherlands
| | - Eden P Go
- the Department of Chemistry, University of Kansas, Lawrence, Kansas 66045
| | - Kwinten Sliepen
- From the Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam, 1105 AZ, The Netherlands
| | - Alba Torrents de la Peña
- From the Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam, 1105 AZ, The Netherlands
| | - Kimberly Badal
- From the Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam, 1105 AZ, The Netherlands
| | - Max Medina-Ramírez
- From the Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam, 1105 AZ, The Netherlands
| | - Wen-Hsin Lee
- the Department of Integrative Structural and Computational Biology, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California 92037, and
| | - Heather Desaire
- the Department of Chemistry, University of Kansas, Lawrence, Kansas 66045
| | - Ian A Wilson
- the Department of Integrative Structural and Computational Biology, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California 92037, and
| | - John P Moore
- the Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10021
| | - Andrew B Ward
- the Department of Integrative Structural and Computational Biology, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California 92037, and
| | - Rogier W Sanders
- From the Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam, 1105 AZ, The Netherlands, .,the Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10021
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4
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van den Kerkhof TLGM, de Taeye SW, Boeser-Nunnink BD, Burton DR, Kootstra NA, Schuitemaker H, Sanders RW, van Gils MJ. HIV-1 escapes from N332-directed antibody neutralization in an elite neutralizer by envelope glycoprotein elongation and introduction of unusual disulfide bonds. Retrovirology 2016; 13:48. [PMID: 27388013 PMCID: PMC4936165 DOI: 10.1186/s12977-016-0279-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 06/21/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Current HIV-1 immunogens are unable to induce antibodies that can neutralize a broad range of HIV-1 (broadly neutralizing antibodies; bNAbs). However, such antibodies are elicited in 10-30 % of HIV-1 infected individuals, and the co-evolution of the virus and the humoral immune responses in these individuals has attracted attention, because they can provide clues for vaccine design. RESULTS Here we characterized the NAb responses and envelope glycoprotein evolution in an HIV-1 infected "elite neutralizer" of the Amsterdam Cohort Studies on HIV-1 infection and AIDS who developed an unusually potent bNAb response rapidly after infection. The NAb response was dependent on the N332-glycan and viral resistance against the N332-glycan dependent bNAb PGT135 developed over time but viral escape did not occur at or near this glycan. In contrast, the virus likely escaped by increasing V1 length, with up to 21 amino acids, accompanied by the introduction of 1-3 additional glycans, as well as 2-4 additional cysteine residues within V1. CONCLUSIONS In the individual studied here, HIV-1 escaped from N332-glycan directed NAb responses without changing the epitope itself, but by elongating a variable loop that shields this epitope.
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Affiliation(s)
- Tom L G M van den Kerkhof
- Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands.,Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
| | - Steven W de Taeye
- Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
| | - Brigitte D Boeser-Nunnink
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
| | - Dennis R Burton
- Department of Immunology and Microbial Science and IAVI Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA, 92037, USA.,Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, 02139, USA
| | - Neeltje A Kootstra
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
| | - Hanneke Schuitemaker
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands.,Janssen Pharmaceuticals, 2333 CN, Leiden, The Netherlands
| | - Rogier W Sanders
- Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands. .,Department of Microbiology and Immunology, Weill Medical College, Cornell University, New York, NY, 10065, USA.
| | - Marit J van Gils
- Department of Microbiology and Immunology, Weill Medical College, Cornell University, New York, NY, 10065, USA.
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5
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Edlefsen PT, Rolland M, Hertz T, Tovanabutra S, Gartland AJ, deCamp AC, Magaret CA, Ahmed H, Gottardo R, Juraska M, McCoy C, Larsen BB, Sanders-Buell E, Carrico C, Menis S, Bose M, RV144 Sequencing Team, Arroyo MA, O’Connell RJ, Nitayaphan S, Pitisuttithum P, Kaewkungwal J, Rerks-Ngarm S, Robb ML, Kirys T, Georgiev IS, Kwong PD, Scheffler K, Pond SLK, Carlson JM, Michael NL, Schief WR, Mullins JI, Kim JH, Gilbert PB. Comprehensive sieve analysis of breakthrough HIV-1 sequences in the RV144 vaccine efficacy trial. PLoS Comput Biol 2015; 11:e1003973. [PMID: 25646817 PMCID: PMC4315437 DOI: 10.1371/journal.pcbi.1003973] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 10/08/2014] [Indexed: 01/25/2023] Open
Abstract
The RV144 clinical trial showed the partial efficacy of a vaccine regimen with an estimated vaccine efficacy (VE) of 31% for protecting low-risk Thai volunteers against acquisition of HIV-1. The impact of vaccine-induced immune responses can be investigated through sieve analysis of HIV-1 breakthrough infections (infected vaccine and placebo recipients). A V1/V2-targeted comparison of the genomes of HIV-1 breakthrough viruses identified two V2 amino acid sites that differed between the vaccine and placebo groups. Here we extended the V1/V2 analysis to the entire HIV-1 genome using an array of methods based on individual sites, k-mers and genes/proteins. We identified 56 amino acid sites or "signatures" and 119 k-mers that differed between the vaccine and placebo groups. Of those, 19 sites and 38 k-mers were located in the regions comprising the RV144 vaccine (Env-gp120, Gag, and Pro). The nine signature sites in Env-gp120 were significantly enriched for known antibody-associated sites (p = 0.0021). In particular, site 317 in the third variable loop (V3) overlapped with a hotspot of antibody recognition, and sites 369 and 424 were linked to CD4 binding site neutralization. The identified signature sites significantly covaried with other sites across the genome (mean = 32.1) more than did non-signature sites (mean = 0.9) (p < 0.0001), suggesting functional and/or structural relevance of the signature sites. Since signature sites were not preferentially restricted to the vaccine immunogens and because most of the associations were insignificant following correction for multiple testing, we predict that few of the genetic differences are strongly linked to the RV144 vaccine-induced immune pressure. In addition to presenting results of the first complete-genome analysis of the breakthrough infections in the RV144 trial, this work describes a set of statistical methods and tools applicable to analysis of breakthrough infection genomes in general vaccine efficacy trials for diverse pathogens.
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Affiliation(s)
- Paul T. Edlefsen
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Morgane Rolland
- US Military HIV Research Program, Silver Spring, Maryland, United States of America
| | - Tomer Hertz
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- The Shraga Segal Dept. of Microbiology, Immunology and Genetics, Faculty of Health Sciences, and The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Sodsai Tovanabutra
- US Military HIV Research Program, Silver Spring, Maryland, United States of America
| | - Andrew J. Gartland
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Allan C. deCamp
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Craig A. Magaret
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Hasan Ahmed
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Raphael Gottardo
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Michal Juraska
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Connor McCoy
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Brendan B. Larsen
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Eric Sanders-Buell
- US Military HIV Research Program, Silver Spring, Maryland, United States of America
| | - Chris Carrico
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- IAVI Neutralizing Antibody Center and Department of Immunology and Microbial Sciences, The Scripps Research Institute, La Jolla, California, United States of America
| | - Sergey Menis
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- IAVI Neutralizing Antibody Center and Department of Immunology and Microbial Sciences, The Scripps Research Institute, La Jolla, California, United States of America
| | - Meera Bose
- US Military HIV Research Program, Silver Spring, Maryland, United States of America
| | | | | | | | | | | | | | | | - Merlin L. Robb
- US Military HIV Research Program, Silver Spring, Maryland, United States of America
| | - Tatsiana Kirys
- Vaccine Research Center, NIAID, NIH, Bethesda, Maryland, United States of America
| | - Ivelin S. Georgiev
- Vaccine Research Center, NIAID, NIH, Bethesda, Maryland, United States of America
| | - Peter D. Kwong
- Vaccine Research Center, NIAID, NIH, Bethesda, Maryland, United States of America
| | - Konrad Scheffler
- Department of Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Sergei L. Kosakovsky Pond
- Department of Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Jonathan M. Carlson
- eSience Research Group, Microsoft Research, Redmond, Washington, United States of America
| | - Nelson L. Michael
- US Military HIV Research Program, Silver Spring, Maryland, United States of America
| | - William R. Schief
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- IAVI Neutralizing Antibody Center and Department of Immunology and Microbial Sciences, The Scripps Research Institute, La Jolla, California, United States of America
- Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - James I. Mullins
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Jerome H. Kim
- US Military HIV Research Program, Silver Spring, Maryland, United States of America
| | - Peter B. Gilbert
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
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Go EP, Hua D, Desaire H. Glycosylation and disulfide bond analysis of transiently and stably expressed clade C HIV-1 gp140 trimers in 293T cells identifies disulfide heterogeneity present in both proteins and differences in O-linked glycosylation. J Proteome Res 2014; 13:4012-27. [PMID: 25026075 PMCID: PMC4156237 DOI: 10.1021/pr5003643] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The HIV-1 envelope protein (Env) mediates viral entry into host cells to initiate infection and is the sole target of antibody-based vaccine development. Significant efforts have been made toward the design, engineering, and expression of various soluble forms of HIV Env immunogen, yet a highly effective immunogen remains elusive. One of the key challenges in the development of an effective HIV vaccine is the presence of the complex set of post-translational modifications (PTMs) on Env, namely, glycosylation and disulfide bonds, that affect protein folding, epitope accessibility, and immunogenecity. Although these PTMs vary with expression systems, variations in Env's PTMs due to changes in the expression method are not yet well established. In this study, we compared the disulfide bond network and glycosylation profiles of clade C recombinant HIV-1 Env trimers, C97ZA012 gp140, expressed by stable and transient transfections using an integrated mass mapping workflow that combines collision induced dissociation (CID) and electron transfer dissociation (ETD). Site-specific analysis of the N- and O-glycosylation profiles revealed that C97ZA012 gp140 produced by both transfection methods displayed a high degree of similarity in N-glycosylation profiles and site occupancy except for one site. By contrast, different O-glycosylation profiles were detected. Analysis of the disulfide bond networks of the Env revealed that both transfection methods yielded C97ZA012 gp140 adopting the expected disulfide bond pattern identified for the monomeric gp120 and gp41 as well as alternative disulfide bond patterns in the C1, V1/V2, and C2 regions. The finding that disulfide bonding is consistently heterogeneous in these proteins is perhaps the most significant outcome of these studies; this disulfide heterogeneity has been reported for multiple other recombinant gp140s, and it is likely present in most recombinantly expressed Env immunogens.
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Affiliation(s)
- Eden P Go
- Department of Chemistry, University of Kansas , Lawrence, Kansas 66047, United States
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Stabilizing exposure of conserved epitopes by structure guided insertion of disulfide bond in HIV-1 envelope glycoprotein. PLoS One 2013; 8:e76139. [PMID: 24146829 PMCID: PMC3797752 DOI: 10.1371/journal.pone.0076139] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 08/26/2013] [Indexed: 11/19/2022] Open
Abstract
Entry of HIV-1 into target cells requires binding of the viral envelope glycoprotein (Env) to cellular receptors and subsequent conformational changes that culminates in fusion of viral and target cell membranes. Recent structural information has revealed that these conformational transitions are regulated by three conserved but potentially flexible layers stacked between the receptor-binding domain (gp120) and the fusion arm (gp41) of Env. We hypothesized that artificial insertion of a covalent bond will ‘snap’ Env into a conformation that is less mobile and stably expose conserved sites. Therefore, we analyzed the interface between these gp120 layers (layers 1, 2 and 3) and identified residues that may form disulfide bonds when substituted with cysteines. We subsequently probed the structures of the resultant mutant gp120 proteins by assaying their binding to a variety of ligands using Surface Plasmon Resonance (SPR) assay. We found that a single disulfide bond strategically inserted between the highly conserved layers 1 and 2 (C65-C115) is able to ‘lock’ gp120 in a CD4 receptor bound conformation (in the absence of CD4), as indicated by the lower dissociation constant (Kd) for the CD4-induced (CD4i) epitope binding 17b antibody. When disulfide-stabilized monomeric (gp120) and trimeric (gp140) Envs were used to immunize rabbits, they were found to elicit a higher proportion of antibodies directed against both CD4i and CD4 binding site epitopes than the wild-type proteins. These results demonstrate that structure-guided stabilization of inter-layer interactions within HIV-1 Env can be used to expose conserved epitopes and potentially overcome the sequence diversity of these molecules.
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8
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Checkley MA, Luttge BG, Freed EO. HIV-1 envelope glycoprotein biosynthesis, trafficking, and incorporation. J Mol Biol 2011; 410:582-608. [PMID: 21762802 PMCID: PMC3139147 DOI: 10.1016/j.jmb.2011.04.042] [Citation(s) in RCA: 350] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 04/14/2011] [Accepted: 04/15/2011] [Indexed: 12/13/2022]
Abstract
The HIV-1 envelope (Env) glycoproteins play an essential role in the virus replication cycle by mediating the fusion between viral and cellular membranes during the entry process. The Env glycoproteins are synthesized as a polyprotein precursor (gp160) that is cleaved by cellular proteases to the mature surface glycoprotein gp120 and the transmembrane glycoprotein gp41. During virus assembly, the gp120/gp41 complex is incorporated as heterotrimeric spikes into the lipid bilayer of nascent virions. These gp120/gp41 complexes then initiate the infection process by binding receptor and coreceptor on the surface of target cells. Much is currently known about the HIV-1 Env glycoprotein trafficking pathway and the structure of gp120 and the extracellular domain of gp41. However, the mechanism by which the Env glycoprotein complex is incorporated into virus particles remains incompletely understood. Genetic data support a major role for the cytoplasmic tail of gp41 and the matrix domain of Gag in Env glycoprotein incorporation. Still to be defined are the identities of host cell factors that may promote Env incorporation and the role of specific membrane microdomains in this process. Here, we review our current understanding of HIV-1 Env glycoprotein trafficking and incorporation into virions.
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Affiliation(s)
- Mary Ann Checkley
- Virus-Cell Interaction Section, HIV Drug Resistance Program National Cancer Institute Frederick, MD 21702
| | - Benjamin G. Luttge
- Virus-Cell Interaction Section, HIV Drug Resistance Program National Cancer Institute Frederick, MD 21702
| | - Eric O. Freed
- Virus-Cell Interaction Section, HIV Drug Resistance Program National Cancer Institute Frederick, MD 21702
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9
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Go EP, Zhang Y, Menon S, Desaire H. Analysis of the disulfide bond arrangement of the HIV-1 envelope protein CON-S gp140 ΔCFI shows variability in the V1 and V2 regions. J Proteome Res 2011; 10:578-91. [PMID: 21114338 PMCID: PMC3075074 DOI: 10.1021/pr100764a] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Disulfide bonding of cysteines is one of the most important protein modifications, and it plays a key role in establishing/maintaining protein structures in biologically active forms. Therefore, the determination of disulfide bond arrangement is one important aspect to understanding the chemical structure of a protein and defining its functional domains. Herein, aiming to understand how the HIV-1 envelope protein's structure influences its immunogenicity, we used an MS-based approach, liquid chromatography electrospray ionization Fourier transform ion cyclotron resonance (LC/ESI-FTICR) mass spectrometry, to determine the disulfide linkages on an oligomeric form of the group M consensus HIV-1 envelope protein (Env), CON-S gp140 ΔCFI. This protein has marked improvement in its immunogenicity compared to monomeric gp120 and wild-type forms of gp140 Envs. Our results demonstrate that the disulfide connectivity in the N-terminal region of CON-S gp140 ΔCFI is different from the disulfide bonding previously reported in the monomeric form of gp120 HIV-1 Env. Additionally, heterogeneity of the disulfide bonding was detected in this region. These data suggest that the V1/V2 region does not have a single, conserved disulfide bonding pattern and that variability could impact immunogenicity of expressed Envs.
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Affiliation(s)
- Eden P. Go
- Department of Chemistry, University of Kansas, Lawrence KS 66047
| | - Ying Zhang
- Department of Chemistry, University of Kansas, Lawrence KS 66047
| | - Sushma Menon
- Department of Chemistry, University of Kansas, Lawrence KS 66047
| | - Heather Desaire
- Department of Chemistry, University of Kansas, Lawrence KS 66047
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10
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Pérez-Losada M, Jobes DV, Sinangil F, Crandall KA, Posada D, Berman PW. Phylodynamics of HIV-1 from a phase-III AIDS vaccine trial in North America. Mol Biol Evol 2009; 27:417-25. [PMID: 19864468 PMCID: PMC2806245 DOI: 10.1093/molbev/msp254] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
In 2003, a phase III placebo-controlled trial (VAX004) of a candidate HIV-1 vaccine (AIDSVAX B/B) was completed in 5,403 volunteers at high risk for HIV-1 infection from North America and the Netherlands. A total of 368 individuals became infected with HIV-1 during the trial. The envelope glycoprotein gene (gp120) from the HIV-1 subtype B viruses infecting 349 patients was sequenced from clinical samples taken as close as possible to the time of diagnosis, rendering a final data set of 1,047 sequences (1,032 from North America and 15 from the Netherlands). Here, we used these data in combination with other sequences available in public databases to assess HIV-1 variation as a function of vaccination treatment, geographic region, race, risk behavior, and viral load. Viral samples did not show any phylogenetic structure for any of these factors, but individuals with different viral loads showed significant differences (P = 0.009) in genetic diversity. The estimated time of emergence of HIV-1 subtype B was 1966-1970. Despite the fact that the number of AIDS cases has decreased in North America since the early 90s, HIV-1 genetic diversity seems to have remained almost constant over time. This study represents one of the largest molecular epidemiologic surveys of viruses responsible for new HIV-1 infections in North America and could help the selection of epidemiologically representative vaccine antigens to include in the next generation of candidate HIV-1 vaccines.
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Affiliation(s)
- Marcos Pérez-Losada
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal.
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11
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O'Rourke SM, Schweighardt B, Scott WG, Wrin T, Fonseca DPAJ, Sinangil F, Berman PW. Novel ring structure in the gp41 trimer of human immunodeficiency virus type 1 that modulates sensitivity and resistance to broadly neutralizing antibodies. J Virol 2009; 83:7728-38. [PMID: 19474108 PMCID: PMC2708639 DOI: 10.1128/jvi.00688-09] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Accepted: 05/18/2009] [Indexed: 11/20/2022] Open
Abstract
The identification of the determinants of sensitivity and resistance to broadly neutralizing antibodies is a high priority for human immunodeficiency virus (HIV) research. An analysis of the swarm of closely related envelope protein variants in an HIV-infected individual revealed a mutation that markedly affected sensitivity to neutralization by antibodies and antiviral entry inhibitors targeting both gp41 and gp120. This mutation mapped to the C34 helix of gp41 and disrupted an unexplored structural feature consisting of a ring of hydrogen bonds in the gp41 trimer. This mutation appeared to affect the assembly of the six-helix bundle required for virus fusion and to alter the conformational equilibria so as to favor the prehairpin intermediate conformation required for the binding of the membrane proximal external region-specific neutralizing antibodies 2F5 and 4E10 and the antiviral drug enfuvirtide (Fuzeon). The "swarm analysis" method we describe furthers our understanding of the relationships among the structure, function, and antigenicity of the HIV envelope protein and represents a new approach to the identification of vaccine antigens.
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Affiliation(s)
- Sara M O'Rourke
- Department of Biomolecular Engineering, University of California, Santa Cruz, CA 95064, USA
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12
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Fromme BJ, Coetsee M, Van Der Watt P, Chan MC, Sperling KM, Katz AA, Flanagan CA. High-affinity binding of southern African HIV type 1 subtype C envelope protein, gp120, to the CCR5 coreceptor. AIDS Res Hum Retroviruses 2008; 24:1527-36. [PMID: 19018669 DOI: 10.1089/aid.2008.0105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
HIV-1 subtype C is the fastest spreading subtype worldwide and predominantly uses the CCR5 coreceptor, showing minimal transition to the X4 phenotype. This raises the possibility that envelope proteins of HIV-1 subtype C have structural features that favor interaction with CCR5. Preference for CCR5 could arise from enhanced affinity of HIV-1 subtype C for CCR5. To test this, we have characterized the interaction of gp120 envelope proteins from HIV-1 subtype C clones with CD4 and CCR5. Recombinant gp120 proteins from isolates of HIV-1 subtypes B and C were expressed, purified, and assessed in a CD4 binding assay and a CCR5 chemokine competition binding assay. All gp120 proteins bound to CD4-expressing cells, except one, 97ZA347ts, which had Arg substituted for the Cys239 in the conserved C2 loop. Reconstitution of Cys239, using site-directed mutagenesis, restored CD4 binding, while introducing Arg or Ser into position 239 of the functional Du151 gp120 protein abrogated CD4 binding. This shows that the Cys228-Cys239 disulfide bond of gp120 is required for high-affinity binding to CD4. Recombinant gp120 proteins from two HIV-1 subtype B clones bound CCR5 in the presence of CD4, while gp120 from the X4-tropic, HxB2, clone did not bind CCR5. gp120 from two functional HIV-1 subtype C clones, Du151 and MOLE1, bound CCR5 with high affinity in the presence of CD4 and Du151 showed significant CCR5 binding in the absence of CD4. A gp120 from a nonfunctional subtype C clone had lower affinity for CCR5. These results indicate that HIV-1 subtype C proteins have high affinity for CCR5 with variable dependence on CD4.
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Affiliation(s)
- Bernhard J. Fromme
- MRC/UCT Research Group for Receptor Biology, University of Cape Town, Cape Town, South Africa
| | - Marla Coetsee
- MRC/UCT Research Group for Receptor Biology, University of Cape Town, Cape Town, South Africa
| | - Pauline Van Der Watt
- MRC/UCT Research Group for Receptor Biology, University of Cape Town, Cape Town, South Africa
| | - Mei-Chi Chan
- MRC/UCT Research Group for Receptor Biology, University of Cape Town, Cape Town, South Africa
| | - Karin M. Sperling
- MRC/UCT Research Group for Receptor Biology, University of Cape Town, Cape Town, South Africa
| | - Arieh A. Katz
- MRC/UCT Research Group for Receptor Biology, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- Department of Clinical Laboratory Sciences, University of Cape Town, Cape Town, South Africa
| | - Colleen A. Flanagan
- MRC/UCT Research Group for Receptor Biology, University of Cape Town, Cape Town, South Africa
- School of Physiology, University of the Witwatersrand, Parktown, South Africa
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Veljkovic V, Veljkovic N, Glisic S, Ho MW. AIDS vaccine: efficacy, safety and ethics. Vaccine 2007; 26:3072-7. [PMID: 18164521 DOI: 10.1016/j.vaccine.2007.11.061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 11/14/2007] [Accepted: 11/23/2007] [Indexed: 10/22/2022]
Abstract
Human immunodeficiency virus (HIV) has infected 50 million people worldwide and killed 16 million so far, and the epidemic is still spreading with 16,000 new cases of HIV infection daily and a projection of 100 million infected individuals by the end of the next decade. There is no question that a safe and effective acquired immunodeficiency syndrome (AIDS) vaccine is urgently needed to bring the current AIDS pandemic under control. But, is preventive AIDS vaccine an attainable goal? Unfortunately, the results of many laboratory and clinical studies over the past two decades are not encouraging. We comment on the efficacy, safety and ethics of AIDS vaccine, and the urgent need for a new strategy for AIDS vaccine development.
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Affiliation(s)
- Veljko Veljkovic
- Center for Multidisciplinary Research, Institute of Nuclear Sciences VINCA, 11001 Belgrade, Serbia.
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Qi X, Xiong S, Yang H, Miller M, Delaney WE. In vitro susceptibility of adefovir-associated hepatitis B virus polymerase mutations to other antiviral agents. AIDS Res Hum Retroviruses 2007. [PMID: 17591025 DOI: 10.1089/aid.2007.9999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Adefovir dipivoxil is a nucleotide prodrug approved for the treatment of chronic hepatitis B. During clinical trials, ADV-associated mutations were observed in 0, 3, 11, 18 and 29% of patients after 48, 96, 144, 192 and 240 weeks of therapy, respectively. Hepatitis B virus (HBV) polymerase mutations associated with virological breakthrough to ADV include rtA181V and rtN236T, which occur alone or in combination. The rtA181T mutation has also been observed at low frequency, alone or in combination with rtN236T. METHODS To investigate the in vitro activity of adefovir and other anti-HBV agents against these mutants, we generated five stable cell lines that each expressed one of the following HBV mutants: rtN236T, rtA181V, rtA181V + rtN236T, rtA181T + rtN236T and rtA181T. Using these cell lines, we quantified in vitro changes in drug susceptibility for eight nucleotide/nucleoside analogues. RESULTS The rtN236T mutant had 7-fold resistance to adefovir but remained sensitive to entecavir, telbivudine and torcitabine (53.2-fold reduced susceptibility). The A181V mutant had 4.3-fold resistance to adefovir and had reduced susceptibility to multiple other agents ranging from 3.2-fold (tenofovir) to >191-fold (clevudine). The A181V + rtN236T double mutant was the most highly resistant showing 18-fold resistance to adefovir and higher levels of resistance to other tested drugs with the exception of tenofovir (10-fold reduced susceptibility). Our results and preliminary clinical data suggest that patients with rtN236T or rtA181V remain susceptible to tenofovir, entecavir and lamivudine. Further clinical data are necessary to precisely define in vitro cutoffs indicative of clinically-relevant resistance, particularly for drugs in development such as emtricitabine, telbivudine, torcitabine and clevudine.
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Affiliation(s)
- Xiaoping Qi
- Department of Clinical Virology, Gilead Sciences, Foster City, CA, USA
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