1
|
Lerner G, Ding L, Candor K, Spearman P. Incorporation of the HIV-1 envelope glycoprotein into viral particles is regulated by the tubular recycling endosome in a cell type-specific manner. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.17.572063. [PMID: 38168173 PMCID: PMC10760151 DOI: 10.1101/2023.12.17.572063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
The HIV-1 envelope glycoprotein (Env) is incorporated into particles during assembly on the plasma membrane (PM). Env initially reaches the PM through the secretory pathway, after which it is rapidly endocytosed via an AP-2- and clathrin-dependent mechanism. Here we show that endocytosed cell surface Env enters the tubular recycling endosome compartment (TRE). Trafficking to the TRE was dependent upon motifs within the CT previously implicated in Env recycling and particle incorporation. Depletion of TRE components MICAL-L1 or EHD1 led to defects in Env incorporation, particle infectivity, and viral replication. Remarkably, defects were limited to cell types defined as nonpermissive for incorporation of CT-deleted Env, including monocyte-derived macrophages, and not observed in 293T, HeLa, or MT-4 cells. This work identifies the TRE as an essential component of Env trafficking and particle incorporation, and provides evidence that the cell type-dependent incorporation of Env is defined by interactions with components of the TRE.
Collapse
Affiliation(s)
- Grigoriy Lerner
- Molecular and Cellular Biosciences, University of Cincinnati College of Medicine, and Infectious Diseases, Cincinnati Children’s Hospital, Cincinnati, OH
| | - Lingmei Ding
- Infectious Diseases, Cincinnati Children’s Hospital Medical Center and University of Cincinnati, Cincinnati, OH
| | - Kathleen Candor
- Immunology Graduate Program, University of Cincinnati College of Medicine, and Infectious Diseases, Cincinnati Children’s Hospital, Cincinnati, OH
| | - Paul Spearman
- Infectious Diseases, Cincinnati Children’s Hospital Medical Center and University of Cincinnati, Cincinnati, OH
| |
Collapse
|
2
|
Nguyen HT, Wang Q, Anang S, Sodroski JG. Characterization of the Human Immunodeficiency Virus (HIV-1) Envelope Glycoprotein Conformational States on Infectious Virus Particles. J Virol 2023; 97:e0185722. [PMID: 36815832 PMCID: PMC10062176 DOI: 10.1128/jvi.01857-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 02/01/2023] [Indexed: 02/24/2023] Open
Abstract
Human immunodeficiency virus (HIV-1) entry into cells involves triggering of the viral envelope glycoprotein (Env) trimer ([gp120/gp41]3) by the primary receptor, CD4, and coreceptors, CCR5 or CXCR4. The pretriggered (State-1) conformation of the mature (cleaved) Env is targeted by broadly neutralizing antibodies (bNAbs), which are inefficiently elicited compared with poorly neutralizing antibodies (pNAbs). Here, we characterize variants of the moderately triggerable HIV-1AD8 Env on virions produced by an infectious molecular proviral clone; such virions contain more cleaved Env than pseudotyped viruses. We identified three types of cleaved wild-type AD8 Env trimers on virions: (i) State-1-like trimers preferentially recognized by bNAbs and exhibiting strong subunit association; (ii) trimers recognized by pNAbs directed against the gp120 coreceptor-binding region and exhibiting weak, detergent-sensitive subunit association; and (iii) a minor gp41-only population. The first Env population was enriched and the other Env populations reduced by introducing State-1-stabilizing changes in the AD8 Env or by treatment of the virions with crosslinker or the State-1-preferring entry inhibitor, BMS-806. These stabilized AD8 Envs were also more resistant to gp120 shedding induced by a CD4-mimetic compound or by incubation on ice. Conversely, a State-1-destabilized, CD4-independent AD8 Env variant exhibited weaker bNAb recognition and stronger pNAb recognition. Similar relationships between Env triggerability and antigenicity/shedding propensity on virions were observed for other HIV-1 strains. State-1 Envs on virions can be significantly enriched by minimizing the adventitious incorporation of uncleaved Env; stabilizing the pretriggered conformation by Env modification, crosslinking or BMS-806 treatment; strengthening Env subunit interactions; and using CD4-negative producer cells. IMPORTANCE Efforts to develop an effective HIV-1 vaccine have been frustrated by the inability to elicit broad neutralizing antibodies that recognize multiple virus strains. Such antibodies can bind a particular shape of the HIV-1 envelope glycoprotein trimer, as it exists on a viral membrane but before engaging receptors on the host cell. Here, we establish simple yet powerful assays to characterize the envelope glycoproteins in a natural context on virus particles. We find that, depending on the HIV-1 strain, some envelope glycoproteins change shape and fall apart, creating decoys that can potentially divert the host immune response. We identify requirements to keep the relevant envelope glycoprotein target for broad neutralizing antibodies intact on virus-like particles. These studies suggest strategies that should facilitate efforts to produce and use virus-like particles as vaccine immunogens.
Collapse
Affiliation(s)
- Hanh T. Nguyen
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Qian Wang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Saumya Anang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Joseph G. Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| |
Collapse
|
3
|
Noailly B, Yaugel-Novoa M, Werquin J, Jospin F, Drocourt D, Bourlet T, Rochereau N, Paul S. Antiviral Activities of HIV-1-Specific Human Broadly Neutralizing Antibodies Are Isotype-Dependent. Vaccines (Basel) 2022; 10:vaccines10060903. [PMID: 35746511 PMCID: PMC9227833 DOI: 10.3390/vaccines10060903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 05/30/2022] [Accepted: 06/02/2022] [Indexed: 02/04/2023] Open
Abstract
Broadly neutralizing antibodies (bNAbs) offer promising opportunities for preventing HIV-1 infection. The protection mechanisms of bNAbs involve the Fc domain, as well as their Fab counterpart. Here, different bNAb isotypes including IgG1, IgA1, IgA2, and IgA122 (IgA2 with the hinge of IgA1) were generated and then produced in CHO cells. Their ability to neutralize pseudovirus and primary HIV-1 isolates were measured, as well as their potential ADCC-like activity using a newly developed assay. In our work, gp41-specific IgA seems to be more efficient than IgG1 in inducing ADCC-like activity, but not in its virus neutralization effect. We show that either gp120-specific IgA or IgG1 isotypes are both efficient in neutralizing different viral strains. In contrast, gp120-specific IgG1 was a better ADCC-like inducer than IgA isotypes. These results provide new insights into the neutralization and ADCC-like activity of different bNAbs that might be taken into consideration when searching for new treatments or antibody-based vaccines.
Collapse
Affiliation(s)
- Blandine Noailly
- CIRI—Centre International de Recherche en Infectiologie, Team GIMAP, Université Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR530, CIC 1408 Vaccinology, 42023 Saint-Etienne, France; (B.N.); (M.Y.-N.); (J.W.); (F.J.); (T.B.); (N.R.)
| | - Melyssa Yaugel-Novoa
- CIRI—Centre International de Recherche en Infectiologie, Team GIMAP, Université Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR530, CIC 1408 Vaccinology, 42023 Saint-Etienne, France; (B.N.); (M.Y.-N.); (J.W.); (F.J.); (T.B.); (N.R.)
| | - Justine Werquin
- CIRI—Centre International de Recherche en Infectiologie, Team GIMAP, Université Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR530, CIC 1408 Vaccinology, 42023 Saint-Etienne, France; (B.N.); (M.Y.-N.); (J.W.); (F.J.); (T.B.); (N.R.)
| | - Fabienne Jospin
- CIRI—Centre International de Recherche en Infectiologie, Team GIMAP, Université Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR530, CIC 1408 Vaccinology, 42023 Saint-Etienne, France; (B.N.); (M.Y.-N.); (J.W.); (F.J.); (T.B.); (N.R.)
| | | | - Thomas Bourlet
- CIRI—Centre International de Recherche en Infectiologie, Team GIMAP, Université Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR530, CIC 1408 Vaccinology, 42023 Saint-Etienne, France; (B.N.); (M.Y.-N.); (J.W.); (F.J.); (T.B.); (N.R.)
| | - Nicolas Rochereau
- CIRI—Centre International de Recherche en Infectiologie, Team GIMAP, Université Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR530, CIC 1408 Vaccinology, 42023 Saint-Etienne, France; (B.N.); (M.Y.-N.); (J.W.); (F.J.); (T.B.); (N.R.)
| | - Stéphane Paul
- CIRI—Centre International de Recherche en Infectiologie, Team GIMAP, Université Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR530, CIC 1408 Vaccinology, 42023 Saint-Etienne, France; (B.N.); (M.Y.-N.); (J.W.); (F.J.); (T.B.); (N.R.)
- Correspondence:
| |
Collapse
|
4
|
Glycosylation of ALV-J envelope protein at sites 17 and 193 is pivotal in the virus replication. J Virol 2021; 96:e0154921. [PMID: 34878920 PMCID: PMC8865534 DOI: 10.1128/jvi.01549-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glycans on envelope glycoprotein (Env) of the subgroup J avian leukosis virus (ALV-J) play an essential role in virion integrity and infection process. In this study, we found that among the 13 predicted N-linked glycosylation sites (NGSs) in gp85 of Tibetan chicken strain TBC-J6, N17 and N193/N191 are pivotal in the virus replication. Further research illustrated that mutation at N193 weakened Env-receptor binding in blocking assay of viral entrance, co-immunoprecipitation and ELISA. Our studies also showed that N17 was involved in Env protein processing and later virion incorporation, based on the detection of p27 and Env protein in the supernatant and gp37 in the cell culture. This report is a systematic research on clarifying the biological function of NGSs on ALV-J gp85, which would provide valuable insights in the role of gp85 in ALV life cycle as well as anti-ALV-J strategies. Importance ALV-J is a retrovirus that can cause multiple types of tumors in chickens. Among all the viral proteins, the heavily glycosylated envelope protein is especially crucial. Glycosylation plays a major role in Env protein function, including protein processing, receptor attachment and immune evasion. Notably, viruses isolated recently seem to lose the 6th and 11st NGSs, which are proved to be important in receptor binding. In our study, the 1st (N17) and 8th (N193) NGS of gp85 of strain TBC-J6 can largely influence the titer of this virus. Deglycosylation at N193 weakened Env-receptor binding, while mutation at N17 influenced Env protein processing. This study systemically analyzed the function of NGSs in ALV-J in different aspects, which may help us to understand the lifecycle of ALV-J and provide antiviral targets for the control of ALV-J.
Collapse
|
5
|
Xiao P, Dienger-Stambaugh K, Chen X, Wei H, Phan S, Beavis AC, Singh K, Adhikary NRD, Tiwari P, Villinger F, He B, Spearman P. Parainfluenza Virus 5 Priming Followed by SIV/HIV Virus-Like-Particle Boosting Induces Potent and Durable Immune Responses in Nonhuman Primates. Front Immunol 2021; 12:623996. [PMID: 33717130 PMCID: PMC7946978 DOI: 10.3389/fimmu.2021.623996] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 01/13/2021] [Indexed: 11/26/2022] Open
Abstract
The search for a preventive vaccine against HIV infection remains an ongoing challenge, indicating the need for novel approaches. Parainfluenza virus 5 (PIV5) is a paramyxovirus replicating in the upper airways that is not associated with any animal or human pathology. In animal models, PIV5-vectored vaccines have shown protection against influenza, RSV, and other human pathogens. Here, we generated PIV5 vaccines expressing HIV envelope (Env) and SIV Gag and administered them intranasally to macaques, followed by boosting with virus-like particles (VLPs) containing trimeric HIV Env. Moreover, we compared the immune responses generated by PIV5-SHIV prime/VLPs boost regimen in naïve vs a control group in which pre-existing immunity to the PIV5 vector was established. We demonstrate for the first time that intranasal administration of PIV5-based HIV vaccines is safe, well-tolerated and immunogenic, and that boosting with adjuvanted trimeric Env VLPs enhances humoral and cellular immune responses. The PIV5 prime/VLPs boost regimen induced robust and durable systemic and mucosal Env-specific antibody titers with functional activities including ADCC and neutralization. This regimen also induced highly polyfunctional antigen-specific T cell responses. Importantly, we show that diminished responses due to PIV5 pre-existing immunity can be overcome in part with VLP protein boosts. Overall, these results establish that PIV5-based HIV vaccine candidates are promising and warrant further investigation including moving on to primate challenge studies.
Collapse
MESH Headings
- AIDS Vaccines/administration & dosage
- AIDS Vaccines/genetics
- AIDS Vaccines/immunology
- Administration, Intranasal
- Animals
- Antibodies, Viral/blood
- Cattle
- Cell Line
- Gene Products, gag/administration & dosage
- Gene Products, gag/genetics
- Gene Products, gag/immunology
- HIV-1/genetics
- HIV-1/immunology
- Host-Pathogen Interactions
- Immunity, Cellular
- Immunity, Humoral
- Immunity, Mucosal
- Immunogenicity, Vaccine
- Macaca mulatta
- Male
- Nasal Mucosa/immunology
- Nasal Mucosa/virology
- Parainfluenza Virus 5/genetics
- Parainfluenza Virus 5/immunology
- Simian Immunodeficiency Virus/genetics
- Simian Immunodeficiency Virus/immunology
- T-Lymphocytes/immunology
- T-Lymphocytes/virology
- Vaccination
- Vaccines, DNA/administration & dosage
- Vaccines, DNA/immunology
- Virion/genetics
- Virion/immunology
- env Gene Products, Human Immunodeficiency Virus/administration & dosage
- env Gene Products, Human Immunodeficiency Virus/genetics
- env Gene Products, Human Immunodeficiency Virus/immunology
Collapse
Affiliation(s)
- Peng Xiao
- New Iberia Research Center, University of Louisiana at Lafayette, New Iberia, LA, United States
| | - Krista Dienger-Stambaugh
- Division of Infectious Diseases, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center and University of Cincinnati, Cincinnati, OH, United States
| | - Xuemin Chen
- Division of Infectious Diseases, Emory University, Atlanta, GA, United States
| | - Huiling Wei
- Department of Infectious Diseases, University of Georgia, Athens, GA, United States
| | - Shannon Phan
- Department of Infectious Diseases, University of Georgia, Athens, GA, United States
| | - Ashley C. Beavis
- Department of Infectious Diseases, University of Georgia, Athens, GA, United States
| | - Karnail Singh
- Division of Infectious Diseases, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center and University of Cincinnati, Cincinnati, OH, United States
| | - Nihar R. Deb Adhikary
- New Iberia Research Center, University of Louisiana at Lafayette, New Iberia, LA, United States
| | - Pooja Tiwari
- Wallace H Coulter Department of Bioengineering, Georgia Institute of Technology, Atlanta, GA, United States
| | - Francois Villinger
- New Iberia Research Center, University of Louisiana at Lafayette, New Iberia, LA, United States
| | - Biao He
- Department of Infectious Diseases, University of Georgia, Athens, GA, United States
| | - Paul Spearman
- Division of Infectious Diseases, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center and University of Cincinnati, Cincinnati, OH, United States
| |
Collapse
|
6
|
Mechanistic Analysis of the Broad Antiretroviral Resistance Conferred by HIV-1 Envelope Glycoprotein Mutations. mBio 2021; 12:mBio.03134-20. [PMID: 33436439 PMCID: PMC7844542 DOI: 10.1128/mbio.03134-20] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Although combination antiretroviral (ARV) therapy is highly effective in controlling the progression of HIV disease, drug resistance can be a major obstacle. Recent findings suggest that resistance can develop without ARV target gene mutations. Despite the effectiveness of antiretroviral (ARV) therapy, virological failure can occur in some HIV-1-infected patients in the absence of mutations in drug target genes. We previously reported that, in vitro, the lab-adapted HIV-1 NL4-3 strain can acquire resistance to the integrase inhibitor dolutegravir (DTG) by acquiring mutations in the envelope glycoprotein (Env) that enhance viral cell-cell transmission. In this study, we investigated whether Env-mediated drug resistance extends to ARVs other than DTG and whether it occurs in other HIV-1 isolates. We demonstrate that Env mutations can reduce susceptibility to multiple classes of ARVs and also increase resistance to ARVs when coupled with target-gene mutations. We observe that the NL4-3 Env mutants display a more stable and closed Env conformation and lower rates of gp120 shedding than the WT virus. We also selected for Env mutations in clinically relevant HIV-1 isolates in the presence of ARVs. These Env mutants exhibit reduced susceptibility to DTG, with effects on replication and Env structure that are HIV-1 strain dependent. Finally, to examine a possible in vivo relevance of Env-mediated drug resistance, we performed single-genome sequencing of plasma-derived virus from five patients failing an integrase inhibitor-containing regimen. This analysis revealed the presence of several mutations in the highly conserved gp120-gp41 interface despite low frequency of resistance mutations in integrase. These results suggest that mutations in Env that enhance the ability of HIV-1 to spread via a cell-cell route may increase the opportunity for the virus to acquire high-level drug resistance mutations in ARV target genes.
Collapse
|
7
|
Nanoparticles presenting clusters of CD4 expose a universal vulnerability of HIV-1 by mimicking target cells. Proc Natl Acad Sci U S A 2020; 117:18719-18728. [PMID: 32690692 PMCID: PMC7414181 DOI: 10.1073/pnas.2010320117] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
CD4-based decoy approaches against HIV-1 are attractive options for long-term viral control, but initial designs, including soluble CD4 (sCD4) and CD4-Ig, were ineffective. To evaluate a therapeutic that more accurately mimics HIV-1 target cells compared with monomeric sCD4 and dimeric CD4-Ig, we generated virus-like nanoparticles that present clusters of membrane-associated CD4 (CD4-VLPs) to permit high-avidity binding of trimeric HIV-1 envelope spikes. In neutralization assays, CD4-VLPs were >12,000-fold more potent than sCD4 and CD4-Ig and >100-fold more potent than the broadly neutralizing antibody (bNAb) 3BNC117, with >12,000-fold improvements against strains poorly neutralized by 3BNC117. CD4-VLPs also neutralized patient-derived viral isolates that were resistant to 3BNC117 and other bNAbs. Intraperitoneal injections of CD4-CCR5-VLP produced only subneutralizing plasma concentrations in HIV-1-infected humanized mice but elicited CD4-binding site mutations that reduced viral fitness. All mutant viruses showed reduced sensitivity to sCD4 and CD4-Ig but remained sensitive to neutralization by CD4-VLPs in vitro. In vitro evolution studies demonstrated that CD4-VLPs effectively controlled HIV-1 replication at neutralizing concentrations, and viral escape was not observed. Moreover, CD4-VLPs potently neutralized viral swarms that were completely resistant to CD4-Ig, suggesting that escape pathways that confer resistance against conventional CD4-based inhibitors are ineffective against CD4-VLPs. These findings suggest that therapeutics that mimic HIV-1 target cells could prevent viral escape by exposing a universal vulnerability of HIV-1: the requirement to bind CD4 on a target cell. We propose that therapeutic and delivery strategies that ensure durable bioavailability need to be developed to translate this concept into a clinically feasible functional cure therapy.
Collapse
|
8
|
Rantalainen K, Berndsen ZT, Antanasijevic A, Schiffner T, Zhang X, Lee WH, Torres JL, Zhang L, Irimia A, Copps J, Zhou KH, Kwon YD, Law WH, Schramm CA, Verardi R, Krebs SJ, Kwong PD, Doria-Rose NA, Wilson IA, Zwick MB, Yates JR, Schief WR, Ward AB. HIV-1 Envelope and MPER Antibody Structures in Lipid Assemblies. Cell Rep 2020; 31:107583. [PMID: 32348769 PMCID: PMC7196886 DOI: 10.1016/j.celrep.2020.107583] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 03/05/2020] [Accepted: 04/07/2020] [Indexed: 11/25/2022] Open
Abstract
Structural and functional studies of HIV envelope glycoprotein (Env) as a transmembrane protein have long been complicated by challenges associated with inherent flexibility of the molecule and the membrane-embedded hydrophobic regions. Here, we present approaches for incorporating full-length, wild-type HIV-1 Env, as well as C-terminally truncated and stabilized versions, into lipid assemblies, providing a modular platform for Env structural studies by single particle electron microscopy. We reconstitute a full-length Env clone into a nanodisc, complex it with a membrane-proximal external region (MPER) targeting antibody 10E8, and structurally define the full quaternary epitope of 10E8 consisting of lipid, MPER, and ectodomain contacts. By aligning this and other Env-MPER antibody complex reconstructions with the lipid bilayer, we observe evidence of Env tilting as part of the neutralization mechanism for MPER-targeting antibodies. We also adapt the platform toward vaccine design purposes by introducing stabilizing mutations that allow purification of unliganded Env with a peptidisc scaffold.
Collapse
Affiliation(s)
- Kimmo Rantalainen
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Zachary T Berndsen
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Aleksandar Antanasijevic
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Torben Schiffner
- Center for HIV/AIDS Vaccine Development, The Scripps Research Institute, La Jolla, CA 92037, USA; Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Xi Zhang
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA, USA
| | - Wen-Hsin Lee
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jonathan L Torres
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Lei Zhang
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Adriana Irimia
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA; Center for HIV/AIDS Vaccine Development, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jeffrey Copps
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Kenneth H Zhou
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Young D Kwon
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - William H Law
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Chaim A Schramm
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Raffaello Verardi
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Shelly J Krebs
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Nicole A Doria-Rose
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA; Center for HIV/AIDS Vaccine Development, The Scripps Research Institute, La Jolla, CA 92037, USA; Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Michael B Zwick
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - John R Yates
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA, USA
| | - William R Schief
- International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA; Center for HIV/AIDS Vaccine Development, The Scripps Research Institute, La Jolla, CA 92037, USA; Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA; Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02129, USA
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA; Center for HIV/AIDS Vaccine Development, The Scripps Research Institute, La Jolla, CA 92037, USA.
| |
Collapse
|
9
|
A Bivalent, Spherical Virus-Like Particle Vaccine Enhances Breadth of Immune Responses against Pathogenic Ebola Viruses in Rhesus Macaques. J Virol 2020; 94:JVI.01884-19. [PMID: 32075939 DOI: 10.1128/jvi.01884-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 02/13/2020] [Indexed: 12/16/2022] Open
Abstract
The 2013-2016 Ebola outbreak in West Africa led to accelerated efforts to develop vaccines against these highly virulent viruses. A live, recombinant vesicular stomatitis virus-based vaccine has been deployed in outbreak settings and appears highly effective. Vaccines based on replication-deficient adenovirus vectors either alone or in combination with a multivalent modified vaccinia Ankara (MVA) Ebola vaccine also appear promising and are progressing in clinical evaluation. However, the ability of current live vector-based approaches to protect against multiple pathogenic species of Ebola is not yet established, and eliciting durable responses may require additional booster vaccinations. Here, we report the development of a bivalent, spherical Ebola virus-like particle (VLP) vaccine that incorporates glycoproteins (GPs) from Zaire Ebola virus (EBOV) and Sudan Ebola virus (SUDV) and is designed to extend the breadth of immunity beyond EBOV. Immunization of rabbits with bivalent Ebola VLPs produced antibodies that neutralized all four pathogenic species of Ebola viruses and elicited antibody-dependent cell-mediated cytotoxicity (ADCC) responses against EBOV and SUDV. Vaccination of rhesus macaques with bivalent VLPs generated strong humoral immune responses, including high titers of binding, as well as neutralizing antibodies and ADCC responses. VLP vaccination led to a significant increase in the frequency of Ebola GP-specific CD4 and CD8 T cell responses. These results demonstrate that a novel bivalent Ebola VLP vaccine elicits strong humoral and cellular immune responses against pathogenic Ebola viruses and support further evaluation of this approach as a potential addition to Ebola vaccine development efforts.IMPORTANCE Ebola outbreaks result in significant morbidity and mortality in affected countries. Although several leading candidate Ebola vaccines have been developed and advanced in clinical testing, additional vaccine candidates may be needed to provide protection against different Ebola species and to extend the durability of protection. A novel approach demonstrated here is to express two genetically diverse glycoproteins on a spherical core, generating a vaccine that can broaden immune responses against known pathogenic Ebola viruses. This approach provides a new method to broaden and potentially extend protective immune responses against Ebola viruses.
Collapse
|
10
|
Salimi H, Johnson J, Flores MG, Zhang MS, O'Malley Y, Houtman JC, Schlievert PM, Haim H. The lipid membrane of HIV-1 stabilizes the viral envelope glycoproteins and modulates their sensitivity to antibody neutralization. J Biol Chem 2019; 295:348-362. [PMID: 31757809 DOI: 10.1074/jbc.ra119.009481] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 11/19/2019] [Indexed: 11/06/2022] Open
Abstract
The envelope glycoproteins (Envs) of HIV-1 are embedded in the cholesterol-rich lipid membrane of the virus. Chemical depletion of cholesterol from HIV-1 particles inactivates their infectivity. We observed that diverse HIV-1 strains exhibit a range of sensitivities to such treatment. Differences in sensitivity to cholesterol depletion could not be explained by variation in Env components known to interact with cholesterol, including the cholesterol-recognition motif and cytoplasmic tail of gp41. Using antibody-binding assays, measurements of virus infectivity, and analyses of lipid membrane order, we found that depletion of cholesterol from HIV-1 particles decreases the conformational stability of Env. It enhances exposure of partially cryptic epitopes on the trimer and increases sensitivity to structure-perturbing treatments such as antibodies and cold denaturation. Substitutions in the cholesterol-interacting motif of gp41 induced similar effects as depletion of cholesterol. Surface-acting agents, which are incorporated into the virus lipid membrane, caused similar effects as disruption of the Env-cholesterol interaction. Furthermore, substitutions in gp120 that increased structural stability of Env (i.e. induced a "closed" conformation of the trimer) increased virus resistance to cholesterol depletion and to the surface-acting agents. Collectively, these results indicate a critical contribution of the viral membrane to the stability of the Env trimer and to neutralization resistance against antibodies. Our findings suggest that the potency of poorly neutralizing antibodies, which are commonly elicited in vaccinated individuals, may be markedly enhanced by altering the lipid composition of the viral membrane.
Collapse
Affiliation(s)
- Hamid Salimi
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Jacklyn Johnson
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Manuel G Flores
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Michael S Zhang
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Yunxia O'Malley
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Jon C Houtman
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Patrick M Schlievert
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Hillel Haim
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242.
| |
Collapse
|
11
|
Smith LK, Kuhn TB, Chen J, Bamburg JR. HIV Associated Neurodegenerative Disorders: A New Perspective on the Role of Lipid Rafts in Gp120-Mediated Neurotoxicity. Curr HIV Res 2019; 16:258-269. [PMID: 30280668 PMCID: PMC6398609 DOI: 10.2174/1570162x16666181003144740] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 09/17/2018] [Accepted: 09/26/2018] [Indexed: 02/07/2023]
Abstract
The implementation of combination antiretroviral therapy (cART) as the primary means of treatment for HIV infection has achieved a dramatic decline in deaths attributed to AIDS and the reduced incidence of severe forms of HIV-associated neurocognitive disorders (HAND) in infected individuals. Despite these advances, milder forms of HAND persist and prevalence of these forms of neurocognitive impairment are rising with the aging population of HIV infected individuals. HIV enters the CNS early in the pathophysiology establishing persistent infection in resident macrophages and glial cells. These infected cells, in turn, secrete neurotoxic viral proteins, inflammatory cytokines, and small metabolites thought to contribute to neurodegenerative processes. The viral envelope protein gp120 has been identified as a potent neurotoxin affecting neurodegeneration via indirect and direct mechanisms involving interactions with chemokine co-receptors CCR5 and CXCR4. This short review focuses on gp120 neurotropism and associated mechanisms of neurotoxicity linked to chemokine receptors CCR5 and CXCR4 with a new perspective on plasma membrane lipid rafts as an active participant in gp120-mediated neurodegeneration underlying HIV induced CNS pathology.
Collapse
Affiliation(s)
- Lisa K Smith
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK, United States
| | - Thomas B Kuhn
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK, United States
| | - Jack Chen
- Department of Biology and Wildlife, Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, United States
| | - James R Bamburg
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, United States
| |
Collapse
|
12
|
Altman J, Liu X, Itri V, Zolla‐Pazner S, Powell R. Optimized protocol for detection of native, full-length HIV-1 envelope on the surface of transfected cells. Health Sci Rep 2018; 1:e74. [PMID: 30623097 PMCID: PMC6266377 DOI: 10.1002/hsr2.74] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 05/23/2018] [Accepted: 06/12/2018] [Indexed: 11/08/2022] Open
Abstract
AIMS Designing therapeutics against the HIV envelope glycoprotein (Env) is only as accurate as the structure of the Env they are targeting. Conserving the structure of the Env trimer is crucial for proper experimental assessment of antibody binding and neutralization. However, Env is notably difficult to express by transfection of a recombinant Env plasmid. To increase surface expression, researchers commonly utilize c-tail mutants of the gp41 transmembrane glycoprotein of HIV-1, but mutations and deletions in this region can impact the overall conformation and stability of the Env trimer. Multiple studies have shown that while tail mutants have higher Env surface expression, they are easier to neutralize and have altered trimer conformations compared with wild-type Env found in vivo on infected cells. To assess and characterize native cell surface Env structures, we sought a protocol that could reliably detect wild-type Env surface expression by flow cytometry. METHODS AND RESULTS By avoiding fetal bovine serum-based buffers, significantly increasing the amounts of transfected plasmid and Env-specific antibody and by selecting a bright, biotin + streptavidin-PE detection system, we were able to increase the surface expression of transfected Env protein. CONCLUSION This protocol will allow for more precise assessment of antibody binding, epitope exposure, and Env structure, all of which will contribute to designing more effective vaccines and immunotherapeutics.
Collapse
Affiliation(s)
- J.B. Altman
- Division of Infectious Diseases, Department of MedicineIcahn School of Medicine at Mount SinaiNew YorkNYUSA
| | - X. Liu
- Division of Infectious Diseases, Department of MedicineIcahn School of Medicine at Mount SinaiNew YorkNYUSA
| | - V. Itri
- Division of Infectious Diseases, Department of MedicineIcahn School of Medicine at Mount SinaiNew YorkNYUSA
| | - S. Zolla‐Pazner
- Division of Infectious Diseases, Department of MedicineIcahn School of Medicine at Mount SinaiNew YorkNYUSA
| | - R.L.R. Powell
- Division of Infectious Diseases, Department of MedicineIcahn School of Medicine at Mount SinaiNew YorkNYUSA
| |
Collapse
|
13
|
HIV-1 R5 Macrophage-Tropic Envelope Glycoprotein Trimers Bind CD4 with High Affinity, while the CD4 Binding Site on Non-macrophage-tropic, T-Tropic R5 Envelopes Is Occluded. J Virol 2018; 92:JVI.00841-17. [PMID: 29118121 DOI: 10.1128/jvi.00841-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 10/24/2017] [Indexed: 12/17/2022] Open
Abstract
HIV-1 R5 variants exploit CCR5 as a coreceptor to infect both T cells and macrophages. R5 viruses that are transmitted or derived from immune tissue and peripheral blood are mainly inefficient at mediating infection of macrophages. In contrast, highly macrophage-tropic (mac-tropic) R5 viruses predominate in brain tissue and can be detected in cerebrospinal fluid but are infrequent in immune tissue or blood even in late disease. These mac-tropic R5 variants carry envelope glycoproteins (Envs) adapted to exploit low levels of CD4 on macrophages to induce infection. However, it is unclear whether this adaptation is conferred by an increased affinity of the Env trimer for CD4 or is mediated by postbinding structural rearrangements in the trimer that enhance the exposure of the coreceptor binding site and facilitate events leading to fusion and virus entry. In this study, we investigated CD4 binding to mac-tropic and non-mac-tropic Env trimers and showed that CD4-IgG binds efficiently to mac-tropic R5 Env trimers, while binding to non-mac-tropic trimers was undetectable. Our data indicated that the CD4 binding site (CD4bs) is highly occluded on Env trimers of non-mac-tropic R5 viruses. Such viruses may therefore infect T cells via viral synapses where Env and CD4 become highly concentrated. This environment will enable high-avidity interactions that overcome extremely low Env-CD4 affinities.IMPORTANCE HIV R5 variants bind to CD4 and CCR5 receptors on T cells and macrophages to initiate infection. Transmitted HIV variants infect T cells but not macrophages, and these viral strains persist in immune tissue even in late disease. Here we show that the binding site for CD4 present on HIV's envelope protein is occluded on viruses replicating in immune tissue. This occlusion likely prevents antibody binding to this site and neutralization of the virus, but it makes it difficult for virus-CD4 interactions to occur. Such viruses probably pass from T cell to T cell via cell contacts where CD4 is highly concentrated and allows infection via inefficient envelope-CD4 binding. Our data are highly relevant for vaccines that aim to induce antibodies targeting the CD4 binding site on the envelope protein.
Collapse
|
14
|
Comparison of Antibody-Dependent Cell-Mediated Cytotoxicity and Virus Neutralization by HIV-1 Env-Specific Monoclonal Antibodies. J Virol 2016; 90:6127-6139. [PMID: 27122574 DOI: 10.1128/jvi.00347-16] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 04/16/2016] [Indexed: 01/07/2023] Open
Abstract
UNLABELLED Although antibodies to the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein have been studied extensively for their ability to block viral infectivity, little data are currently available on nonneutralizing functions of these antibodies, such as their ability to eliminate virus-infected cells by antibody-dependent cell-mediated cytotoxicity (ADCC). HIV-1 Env-specific antibodies of diverse specificities, including potent broadly neutralizing and nonneutralizing antibodies, were therefore tested for ADCC against cells infected with a lab-adapted HIV-1 isolate (HIV-1NL4-3), a primary HIV-1 isolate (HIV-1JR-FL), and a simian-human immunodeficiency virus (SHIV) adapted for pathogenic infection of rhesus macaques (SHIVAD8-EO). In accordance with the sensitivity of these viruses to neutralization, HIV-1NL4-3-infected cells were considerably more sensitive to ADCC, both in terms of the number of antibodies and magnitude of responses, than cells infected with HIV-1JR-FL or SHIVAD8-EO ADCC activity generally correlated with antibody binding to Env on the surfaces of virus-infected cells and with viral neutralization; however, neutralization was not always predictive of ADCC, as instances of ADCC in the absence of detectable neutralization, and vice versa, were observed. These results reveal incomplete overlap in the specificities of antibodies that mediate these antiviral activities and provide insights into the relationship between ADCC and neutralization important for the development of antibody-based vaccines and therapies for combating HIV-1 infection. IMPORTANCE This study provides fundamental insights into the relationship between antibody-dependent cell-mediated cytotoxicity (ADCC) and virus neutralization that may help to guide the development of antibody-based vaccines and immunotherapies for the prevention and treatment of HIV-1 infection.
Collapse
|
15
|
Tedbury PR, Freed EO. The cytoplasmic tail of retroviral envelope glycoproteins. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 129:253-84. [PMID: 25595807 DOI: 10.1016/bs.pmbts.2014.10.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Retroviruses comprise a large, diverse group that infects a broad range of host organisms. Pathogenicity varies widely; the human immunodeficiency virus is the causative agent of acquired immunodeficiency syndrome, one of the world's leading infectious causes of death, while many nonhuman retroviruses cause cancer in the host. Retroviruses have been studied intensively, and great strides have been made in understanding aspects of retroviral biology. While the principal functions of the viral structural proteins are well understood, there remain many incompletely characterized domains. One of these is the cytoplasmic tail (CT) of the envelope glycoprotein. Several functions of the CT are highly conserved, whereas other properties are unique to a specific retrovirus. For example, the lentiviruses encode envelope glycoproteins with particularly large cytoplasmic domains. The functions of the long lentiviral envelope CT are still being deciphered. The reported functions of retroviral envelope CTs are discussed in this chapter.
Collapse
Affiliation(s)
- Philip R Tedbury
- Virus-Cell Interaction Section, HIV Drug Resistance Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Eric O Freed
- Virus-Cell Interaction Section, HIV Drug Resistance Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA.
| |
Collapse
|
16
|
Chazal M, Nzounza P, Pique C, Ramirez BC. Loss of infectivity of HIV-1 particles produced by mobile lymphocytes. PLoS One 2014; 9:e109601. [PMID: 25295863 PMCID: PMC4190309 DOI: 10.1371/journal.pone.0109601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 09/11/2014] [Indexed: 11/19/2022] Open
Abstract
HIV-1 spreads by cell-free particles and through direct cell contacts. To discriminate between these two modes of dissemination, an assay in which the cells are cultured under shaking conditions impairing cell-to-cell transmission has been described. We addressed the impact of shaking on HIV-1 particle infectivity. Kinetics of HIV-1 infection in static or shaking conditions confirmed that HIV-1 replication is reduced in mobile lymphocyte T cells. Strikingly, the infectivity of viruses produced by mobile lymphocytes was dramatically reduced. In parallel, the amount of envelope protein present on these particles showed a continuous decrease over time. We conclude that inefficient HIV-1 replication in mobile lymphocytes in this experimental system is not only due to avoidance of viral cell-to-cell transfer but also to the loss of infectivity of the viral particles due to the alteration of the composition and functionality of the particles produced by these lymphocytes. It is important to take these observations into account when studying viral transmission under shaking conditions.
Collapse
Affiliation(s)
- Maxime Chazal
- INSERM, U1016, Institut Cochin, Paris, France
- CNRS, UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Patrycja Nzounza
- INSERM, U1016, Institut Cochin, Paris, France
- CNRS, UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Claudine Pique
- INSERM, U1016, Institut Cochin, Paris, France
- CNRS, UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Bertha Cecilia Ramirez
- INSERM, U1016, Institut Cochin, Paris, France
- CNRS, UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
- * E-mail:
| |
Collapse
|
17
|
Tong T, Crooks ET, Osawa K, Robinson JE, Barnes M, Apetrei C, Binley JM. Multi-parameter exploration of HIV-1 virus-like particles as neutralizing antibody immunogens in guinea pigs, rabbits and macaques. Virology 2014; 456-457:55-69. [PMID: 24889225 DOI: 10.1016/j.virol.2014.03.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 02/26/2014] [Accepted: 03/13/2014] [Indexed: 12/18/2022]
Abstract
Virus-like particles (VLPs) offer a platform to test the hypothesis that, since antibody binding to native envelope glycoprotein (Env) trimers results in HIV-1 neutralization, that native Env trimers presented in membranes may be useful for inducing neutralizing antibodies (nAbs) in a vaccine setting. So far, VLPs have not fulfilled this potential. Here, using a "shotgun" approach, we evaluated a wide cross-section of variables in a series of VLP immunizations. We identified 3 tentative leads. First, that VLP doses may not have been sufficient for optimal nAb induction. Second, that dampening the antigenicity of non-functional Env (for example uncleaved gp160) using either protease digests or IgG masking may be useful. Third, that guinea pig sera preferentially target non-conserved epitopes and exhibit relatively high background activity, suggesting that rabbits may be preferable as small animal vaccine models. Recent immunogenicity studies in rabbits appear to bear out all 3 of these leads.
Collapse
Affiliation(s)
- Tommy Tong
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, CA 92121, USA
| | - Ema T Crooks
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, CA 92121, USA
| | - Keiko Osawa
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, CA 92121, USA
| | - James E Robinson
- Tulane University, 1430 Tulane Avenue, New Orleans, LA 70112, USA
| | - Mary Barnes
- Tulane National Primate Research Center, 18703 Three Rivers Road, Covington, LA 70433, USA
| | - Cristian Apetrei
- Tulane National Primate Research Center, 18703 Three Rivers Road, Covington, LA 70433, USA
| | - James M Binley
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, CA 92121, USA.
| |
Collapse
|
18
|
Wang W, Nie J, Prochnow C, Truong C, Jia Z, Wang S, Chen XS, Wang Y. A systematic study of the N-glycosylation sites of HIV-1 envelope protein on infectivity and antibody-mediated neutralization. Retrovirology 2013; 10:14. [PMID: 23384254 PMCID: PMC3648360 DOI: 10.1186/1742-4690-10-14] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 02/04/2013] [Indexed: 12/29/2022] Open
Abstract
Background Glycans on the human immunodeficiency virus (HIV) envelope glycoprotein (Env) play an important role in viral infection and evasion of neutralization by antibodies. In this study, all 25 potential N-linked glycosylation sites (PNGS) on the HIV-1 CRF07_BC Env, FE, were mutated individually to study the effect of their removal on viral infectivity, virion production, and antibody-mediated neutralization. Results Removal of specific N-glycosylation sites has a significant effect on viral infectivity and antibody-mediated neutralization phenotype. Six of these glycosylation mutants located on the V1/V2 and C1/C2 domains lost infectivity. PNGS mutations located on V4/C4/V5 (except N392 on V4), were shown to increase viral infectivity. Furthermore, FE is much more dependent on specific glycans than clade B Env YU-2. On neutralization effect, PNGS mutations at N197 (C2), N301 (V3), N442 (C4) and N625 (gp41) rendered the virus more susceptible to neutralization by the monoclonal antibodies (MAbs) that recognize the CD4 binding site or gp41. Generally, mutations on V4/V5 loops, C2/C3/C4 regions and gp41 reduced the neutralization sensitivity to PG16. However, mutation of N289 (C2) made the virus more sensitive to both PG9 and PG16. Furthermore, we showed that mutations at N142 (V1), N355 (C3) and N463 (V5) conferred resistance to neutralization by anti-gp41 MAbs. We used the available structural information of HIV Env and homology modeling to provide a structural basis for the observed biological effects of these mutations. Conclusions This report provides the first systematic experimental account of the biological role of the entire PNGS on an HIV-1 Env, which should provide valuable insights for understanding the function of Env in HIV infection cycle and for developing future anti-HIV strategies.
Collapse
Affiliation(s)
- Wenbo Wang
- Department of Cell Biology, National Institutes for Food and Drug Control, No. 2 Tiantanxili, Beijing 100050, P.R. China
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Koukuntla R, Mandell RB, Flick R. Virus-Like Particle-Based Countermeasures Against Rift Valley Fever Virus. Zoonoses Public Health 2012; 59 Suppl 2:142-50. [DOI: 10.1111/j.1863-2378.2012.01478.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
20
|
Kong L, Sattentau QJ. Antigenicity and Immunogenicity in HIV-1 Antibody-Based Vaccine Design. ACTA ACUST UNITED AC 2012; S8:3. [PMID: 23227445 DOI: 10.4172/2155-6113] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Neutralizing antibodies can protect from infection by immunodeficiency viruses. However, the induction by active vaccination of antibodies that can potently neutralize a broad range of circulating virus strains is a goal not yet achieved, despite more than 2 decades of research. Here we review progress made in the field, from early empirical studies to today's rational structure-based vaccine antigen design. We discuss the existence of broadly neutralizing antibodies, their implications for epitope discovery and recent progress made in antigen design. Finally, we consider the relationship between antigenicity and immunogenicity for B cell recognition and antibody production, a major hurdle for rational vaccine design to overcome.
Collapse
Affiliation(s)
- Leopold Kong
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK ; The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | | |
Collapse
|
21
|
Maturation-induced cloaking of neutralization epitopes on HIV-1 particles. PLoS Pathog 2011; 7:e1002234. [PMID: 21931551 PMCID: PMC3169560 DOI: 10.1371/journal.ppat.1002234] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Accepted: 07/08/2011] [Indexed: 11/19/2022] Open
Abstract
To become infectious, HIV-1 particles undergo a maturation process involving proteolytic cleavage of the Gag and Gag-Pol polyproteins. Immature particles contain a highly stable spherical Gag lattice and are impaired for fusion with target cells. The fusion impairment is relieved by truncation of the gp41 cytoplasmic tail (CT), indicating that an interaction between the immature viral core and gp41 within the particle represses HIV-1 fusion by an unknown mechanism. We hypothesized that the conformation of Env on the viral surface is regulated allosterically by interactions with the HIV-1 core during particle maturation. To test this, we quantified the binding of a panel of monoclonal antibodies to mature and immature HIV-1 particles by immunofluorescence imaging. Surprisingly, immature particles exhibited markedly enhanced binding of several gp41-specific antibodies, including two that recognize the membrane proximal external region (MPER) and neutralize diverse HIV-1 strains. Several of the differences in epitope exposure on mature and immature particles were abolished by truncation of the gp41 CT, thus linking the immature HIV-1 fusion defect with altered Env conformation. Our results suggest that perturbation of fusion-dependent Env conformational changes contributes to the impaired fusion of immature particles. Masking of neutralization-sensitive epitopes during particle maturation may contribute to HIV-1 immune evasion and has practical implications for vaccine strategies targeting the gp41 MPER. The conformation of HIV-1 Env is of tremendous importance from an immunological standpoint. While several human monoclonal antibodies that exhibit broadly neutralizing activity have been identified, efforts to elicit such antibodies have met with minimal success. Here, we show that the conformation of Env is altered on the surface of immature vs. mature HIV-1 particles in such a way that certain epitopes recognized by some broadly neutralizing antibodies are more exposed on immature virions. This maturation-dependent conformational masking may represent an important mechanism of HIV-1 immune evasion.
Collapse
|
22
|
Bhakta SJ, Shang L, Prince JL, Claiborne DT, Hunter E. Mutagenesis of tyrosine and di-leucine motifs in the HIV-1 envelope cytoplasmic domain results in a loss of Env-mediated fusion and infectivity. Retrovirology 2011; 8:37. [PMID: 21569545 PMCID: PMC3117779 DOI: 10.1186/1742-4690-8-37] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 05/14/2011] [Indexed: 12/30/2022] Open
Abstract
Background The gp41 component of the Human Immunodeficiency Virus (HIV) envelope glycoprotein (Env) contains a long cytoplasmic domain (CD) with multiple highly conserved tyrosine (Y) and dileucine (LL) motifs. Studies suggest that the motifs distal to major endocytosis motif (Y712HRL), located at residues 712-715 of Env, may contribute to Env functionality in the viral life cycle. In order to examine the biological contribution of these motifs in the biosynthesis, transport, and function of Env, we constructed two panels of mutants in which the conserved Y- and LL-motifs were sequentially substituted by alternative residues, either in the presence or absence of Y712. Additional mutants targeting individual motifs were then constructed. Results All mutant Envs, when expressed in the absence of other viral proteins, maintained at least WT levels of Env surface staining by multiple antibodies. The Y712 mutation (Y712C) contributed to at least a 4-fold increase in surface expression for all mutants containing this change. Sequential mutagenesis of the Y- and LL-motifs resulted in a generally progressive decrease in Env fusogenicity. However, additive mutation of dileucine and tyrosine motifs beyond the tyrosine at residue 768 resulted in the most dramatic effects on Env incorporation into virions, viral infectivity, and virus fusion with target cells. Conclusions From the studies reported here, we show that mutations of the Y- and LL-motifs, which effectively eliminate the amphipathic nature of the lytic peptide 2 (LLP2) domain or disrupt YW and LL motifs in a region spanning residues 795-803 (YWWNLLQYW), just C-terminal of LLP2, can dramatically interfere with biological functions of HIV-1 Env and abrogate virus replication. Because these mutant proteins are expressed at the cell surface, we conclude that tyrosine and di-leucine residues within the cytoplasmic domain of gp41 play critical roles in HIV-1 replication that are distinct from that of targeting the plasma membrane.
Collapse
Affiliation(s)
- Sushma J Bhakta
- Emory Vaccine Center at the Yerkes National Primate Research Center and Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia 30329, USA
| | | | | | | | | |
Collapse
|
23
|
Emerging studies of human HIV-specific antibody repertoires. Vaccine 2010; 28 Suppl 2:B18-23. [PMID: 20510738 DOI: 10.1016/j.vaccine.2010.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2009] [Revised: 01/30/2010] [Accepted: 02/01/2010] [Indexed: 11/22/2022]
Abstract
There has been an explosion of interest in the human B cell response to HIV infection of late. Recent advances in techniques for isolation of human antibodies and antibody secreting cell lines have facilitated a rapid expansion in the number of antibodies available for study. Early analysis of these repertoires reveals interesting features of the HIV-specific antibody response. HIV-specific repertoires exhibit a high level of clonality in circulating cells, and high levels of somatic mutations within the antibody variable gene segments. It appears that many if not most antibodies in circulation bind to virus envelope conformations that are found only in complex oligomeric structures on virion particles or virus-like particles. The rapid isolation of large panels of novel human neutralizing antibodies promises to reveal new insights into the fundamental principles underlying antibody-mediated neutralization of HIV.
Collapse
|
24
|
Hicar MD, Chen X, Briney B, Hammonds J, Wang JJ, Kalams S, Spearman PW, Crowe JE. Pseudovirion particles bearing native HIV envelope trimers facilitate a novel method for generating human neutralizing monoclonal antibodies against HIV. J Acquir Immune Defic Syndr 2010; 54:223-35. [PMID: 20531016 PMCID: PMC2930513 DOI: 10.1097/qai.0b013e3181dc98a3] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Monomeric HIV envelope vaccines fail to elicit broadly neutralizing antibodies or to protect against infection. Neutralizing antibodies against HIV bind to native functionally active Env trimers on the virion surface. Gag-Env pseudovirions recapitulate the native trimer and could serve as an effective epitope presentation platform for study of the neutralizing antibody response in HIV-infected individuals. To address if pseudovirions can recapitulate native HIV virion epitope structures, we carefully characterized these particles, concentrating on the antigenic structure of the coreceptor binding site. By blue native gel shift assays, Gag-Env pseudovirions were shown to contain native trimers that were competent for binding to neutralizing monoclonal antibodies. In enzyme-linked immunosorbent assay, pseudovirions exhibited increased binding of known CD4-induced antibodies after addition of CD4. Using flow cytometric analysis, fluorescently labeled pseudovirions specifically identified a subset of antigen-specific B cells in HIV-infected subjects. Interestingly, the sequence of one of these novel human antibodies, identified during cloning of single HIV-specific B cells and designated 2C6, exhibited homology to mAb 47e, a known anti-CD4-induced coreceptor binding site antibody. The secreted monoclonal antibody 2C6 did not bind monomeric gp120, but specifically bound envelope on pseudovirions. A recombinant form of the antibody 2C6 acted as a CD4-induced epitope-specific antibody in neutralization assays, yet did not bind monomeric gp120. These findings imply specificity against a quaternary epitope presented on the pseudovirion envelope spike. These data demonstrate that Gag-Env pseudovirions recapitulate CD4 and coreceptor binding pocket antigenic structures and can facilitate identification of B-cell clones that secrete neutralizing antibodies.
Collapse
Affiliation(s)
- Mark D. Hicar
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Xuemin Chen
- Department of Pediatrics, Emory University, School of Medicine, Atlanta, GA 30322, USA
- Children’s Healthcare of Atlanta, Atlanta, GA 30329, USA
| | - Bryan Briney
- Department of Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jason Hammonds
- Department of Pediatrics, Emory University, School of Medicine, Atlanta, GA 30322, USA
- Children’s Healthcare of Atlanta, Atlanta, GA 30329, USA
| | - Jaang-Jiun Wang
- Department of Pediatrics, Emory University, School of Medicine, Atlanta, GA 30322, USA
- Children’s Healthcare of Atlanta, Atlanta, GA 30329, USA
| | - Spyros Kalams
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Paul W. Spearman
- Department of Pediatrics, Emory University, School of Medicine, Atlanta, GA 30322, USA
- Department of Microbiology and Immunology, Emory University, School of Medicine, Atlanta, GA 30322, USA
- Children’s Healthcare of Atlanta, Atlanta, GA 30329, USA
| | - James E. Crowe
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Program in Vaccine Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| |
Collapse
|
25
|
Mandell RB, Koukuntla R, Mogler LJ, Carzoli AK, Freiberg AN, Holbrook MR, Martin BK, Staplin WR, Vahanian NN, Link CJ, Flick R. A replication-incompetent Rift Valley fever vaccine: chimeric virus-like particles protect mice and rats against lethal challenge. Virology 2010; 397:187-98. [PMID: 19932911 PMCID: PMC2813982 DOI: 10.1016/j.virol.2009.11.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 10/27/2009] [Accepted: 11/02/2009] [Indexed: 11/09/2022]
Abstract
Virus-like particles (VLPs) present viral antigens in a native conformation and are effectively recognized by the immune system and therefore are considered as suitable and safe vaccine candidates against many viral diseases. Here we demonstrate that chimeric VLPs containing Rift Valley fever virus (RVFV) glycoproteins G(N) and G(C), nucleoprotein N and the gag protein of Moloney murine leukemia virus represent an effective vaccine candidate against Rift Valley fever, a deadly disease in humans and livestock. Long-lasting humoral and cellular immune responses are demonstrated in a mouse model by the analysis of neutralizing antibody titers and cytokine secretion profiles. Vaccine efficacy studies were performed in mouse and rat lethal challenge models resulting in high protection rates. Taken together, these results demonstrate that replication-incompetent chimeric RVF VLPs are an efficient RVFV vaccine candidate.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | - Nicholas N. Vahanian
- BioProtection Systems Corporation, Ames, IA, USA,NewLink Genetics Corporation, Ames, IA, USA
| | - Charles J. Link
- BioProtection Systems Corporation, Ames, IA, USA,NewLink Genetics Corporation, Ames, IA, USA
| | - Ramon Flick
- BioProtection Systems Corporation, Ames, IA, USA,Corresponding author. Fax: +1 515 296 3820
| |
Collapse
|
26
|
Truncation of the membrane-spanning domain of human immunodeficiency virus type 1 envelope glycoprotein defines elements required for fusion, incorporation, and infectivity. J Virol 2009; 83:11588-98. [PMID: 19726514 DOI: 10.1128/jvi.00914-09] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The membrane-spanning domain (MSD) of the envelope (Env) glycoprotein from human (HIV) and simian immunodeficiency viruses plays a key role in anchoring the Env complex into the viral membrane but also contributes to its biological function in fusion and virus entry. In HIV type 1 (HIV-1), it has been predicted to span 27 amino acids, from lysine residue 681 to arginine 707, and encompasses an internal arginine at residue 694. By examining a series of C-terminal-truncation mutants of the HIV-1 gp41 glycoprotein that substituted termination codons for amino acids 682 to 708, we show that this entire region is required for efficient viral infection of target cells. Truncation to the arginine at residue 694 resulted in an Env complex that was secreted from the cells. In contrast, a region from residues 681 to 698, which contains highly conserved hydrophobic residues and glycine motifs and extends 4 amino acids beyond 694R, can effectively anchor the protein in the membrane, allow efficient transport to the plasma membrane, and mediate wild-type levels of cell-cell fusion. However, these fusogenic truncated Env mutants are inefficiently incorporated into budding virions. Based on the analysis of these mutants, a "snorkeling" model, in which the flanking charged amino acid residues at 681 and 694 are buried in the lipid while their side chains interact with polar head groups, is proposed for the HIV-1 MSD.
Collapse
|
27
|
Role of the membrane-spanning domain of human immunodeficiency virus type 1 envelope glycoprotein in cell-cell fusion and virus infection. J Virol 2008; 82:5417-28. [PMID: 18353944 DOI: 10.1128/jvi.02666-07] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The membrane-spanning domain (MSD) of the human immunodeficiency virus type 1 (HIV-1) gp41 glycoprotein is critical for its biological activity. Previous C-terminal truncation studies have predicted an almost invariant core structure of 12 amino acid residues flanked by basic amino acids in the HIV-1 MSD that function to anchor the glycoprotein in the lipid bilayer. To further understand the role of specific amino acids within the MSD core, we initially replaced the core region with 12 leucine residues and then constructed recovery-of-function mutants in which specific amino acid residues (including a GGXXG motif) were reintroduced. We show here that conservation of the MSD core sequence is not required for normal expression, processing, intracellular transport, and incorporation into virions of the envelope glycoprotein (Env). However, the amino acid composition of the MSD core does influence the ability of Env to mediate cell-cell fusion and plays a critical role in the infectivity of HIV-1. Replacement of conserved amino acid residues with leucine blocked virus-to-cell fusion and subsequent viral entry into target cells. This restriction could not be released by C-terminal truncation of the gp41 glycoprotein. These studies imply that the highly conserved core residues of the HIV Env MSD, in addition to serving as a membrane anchor, play an important role in mediating membrane fusion during viral entry.
Collapse
|
28
|
Advances in methods for the production, purification, and characterization of HIV-1 Gag–Env pseudovirion vaccines. Vaccine 2007; 25:8036-48. [DOI: 10.1016/j.vaccine.2007.09.016] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2007] [Revised: 09/04/2007] [Accepted: 09/06/2007] [Indexed: 11/21/2022]
|
29
|
Crooks ET, Moore PL, Franti M, Cayanan CS, Zhu P, Jiang P, de Vries RP, Wiley C, Zharkikh I, Schülke N, Roux KH, Montefiori DC, Burton DR, Binley JM. A comparative immunogenicity study of HIV-1 virus-like particles bearing various forms of envelope proteins, particles bearing no envelope and soluble monomeric gp120. Virology 2007; 366:245-62. [PMID: 17580087 PMCID: PMC2080857 DOI: 10.1016/j.virol.2007.04.033] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Revised: 03/08/2007] [Accepted: 04/24/2007] [Indexed: 10/23/2022]
Abstract
To assess the potential of native Envelope glycoprotein (Env) trimers as neutralizing antibody vaccines, we immunized guinea pigs with three types of VLPs and soluble gp120. Particles included "SOS-VLPs" (bearing disulfide-shackled functional trimers), "UNC-VLPs" (bearing uncleaved nonfunctional Env) and "naked VLPs" (bearing no Env). The SOS-VLPs were found to have a density of about 27 native trimers per particle, approximately twice that of live inactivated HIV-1 preparations. As immunogens, UNC- and SOS-VLP rapidly elicited anti-gp120 antibodies focused on the V3 loop and the gp120 coreceptor binding site. Reactivity to the gp41 immunodominant domain was absent in SOS-VLP sera, presumably because gp120-gp41 association is stabilized, effectively covering this epitope. Gp120-immune sera reacted with the receptor binding sites of gp120 and were less focused on the V3 loop. Some Env-VLP sera neutralized primary isolates at modest titers. The measurement of neutralization was found to be affected by the cell lines used. Depending on the assay particulars, non-Env specific antibodies in VLP sera could enhance infection, or nonspecifically neutralize. However, a neutralization assay using TZM-BL cells was essentially clear of these effects. We also describe a native trimer binding assay to confirm neutralization activity in a manner that completely eliminates nonspecific effects. Overall, our data suggests that Env-VLP sera were primarily focused on nonfunctional forms of Env on VLP surfaces, possibly gp120/gp41 monomers and not the trimers. Therefore, to make progress toward a more effective VLP-based vaccine, we will need to find ways to refocus the attention of B cells on native trimers.
Collapse
Affiliation(s)
- Emma T. Crooks
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, CA 92121
| | - Penny L. Moore
- National Institute for Communicable Diseases, Sandringham, Johannesburg, South Africa
| | - Michael Franti
- Progenics Pharmaceuticals, 777 Old Saw Mill River Rd., Tarrytown, NY 10591
| | | | - Ping Zhu
- Department of Biological Science, and Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306
| | - Pengfei Jiang
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, CA 92121
| | - Robbert P. de Vries
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, CA 92121
- Department of Human Retrovirology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Cheryl Wiley
- The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla CA 92037
| | - Irina Zharkikh
- The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla CA 92037
| | - Norbert Schülke
- Millennium Pharmaceuticals, Inc., 35 Landsdowne Street, Cambridge, MA 02139
| | - Kenneth H. Roux
- Department of Biological Science, and Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306
| | - David C. Montefiori
- Duke University, Department of Surgery, La Salle Straight Extensions, Durham, NC 27710
| | - Dennis R. Burton
- The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla CA 92037
| | - James M. Binley
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, CA 92121
- *corresponding author: James M. Binley, Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego CA 92121. tel: (858) 909 5142. fax: (858) 455 3804.
| |
Collapse
|
30
|
McBurney SP, Young KR, Ross TM. Membrane embedded HIV-1 envelope on the surface of a virus-like particle elicits broader immune responses than soluble envelopes. Virology 2006; 358:334-46. [PMID: 17011011 DOI: 10.1016/j.virol.2006.08.032] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Revised: 08/07/2006] [Accepted: 08/22/2006] [Indexed: 11/24/2022]
Abstract
Virally regulated HIV-1 particles were expressed from DNA plasmids encoding Gag, protease, reverse transcriptase, Vpu, Tat, Rev, and Env. The sequences for integrase, Vpr, Vif, Nef, and the long terminal repeats (LTRs) were deleted. Mutations were engineered into the VLP genome to produce particles deficient in activities associated with viral reverse transcriptase, RNase H, and RNA packaging. Each plasmid efficiently secreted particles from primate cells in vitro and particles were purified from the supernatants and used as immunogens. Mice (BALB/c) were vaccinated intranasally (day 1 and weeks 3 and 6) with purified VLPs and the elicited immunity was compared to particles without Env (Gag(p55)), to soluble monomeric Env(gp120), or to soluble trimerized Env(gp140). Only mice vaccinated with VLPs had robust anti-Env cellular immunity. In contrast, all mice had high titer anti-Env serum antibody (IgG). However, VLP-vaccinated mice had antisera that detected a broader number of linear Env peptides, had anti-Env mucosal IgA and IgG, as well as higher titers of serum neutralizing antibodies. VLPs elicited high titer antibodies that recognized linear regions in V4-C5 and the ectodomain of gp41, but did not recognize V3. These lentiviral VLPs are effective mucosal immunogens that elicit broader immunity against Env determinants in both the systemic and mucosal immune compartments than soluble forms of Env.
Collapse
Affiliation(s)
- Sean P McBurney
- Center for Vaccine Research for Emerging Diseases and Biodefense, University of Pittsburgh School of Medicine, 9047 Biomedical Sciences Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15261, USA
| | | | | |
Collapse
|
31
|
Davis MR, Jiang J, Zhou J, Freed EO, Aiken C. A mutation in the human immunodeficiency virus type 1 Gag protein destabilizes the interaction of the envelope protein subunits gp120 and gp41. J Virol 2006; 80:2405-17. [PMID: 16474147 PMCID: PMC1395406 DOI: 10.1128/jvi.80.5.2405-2417.2006] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The Gag protein of human immunodeficiency virus type 1 (HIV-1) associates with the envelope protein complex during virus assembly. The available evidence indicates that this interaction involves recognition of the gp41 cytoplasmic tail (CT) by the matrix protein (MA) region of Pr55(Gag). Here we show that substitution of Asp for Leu at position 49 (L49D) in MA results in a specific reduction in particle-associated gp120 without affecting the levels of gp41. Mutant virions were markedly reduced in single-cycle infectivity despite a relatively modest defect in fusion with target cells. Studies with HIV-1 particles containing decreased levels of envelope proteins suggested that the L49D mutation also inhibits a postentry step in infection. Truncation of the gp41 tail, or pseudotyping by vesicular stomatitis virus glycoprotein, restored both the fusion and infectivity of L49D mutant virions to wild-type levels. Truncation of gp41 also resulted in equivalent levels of gp120 on particles with and without the MA mutation and enhanced the replication of the L49D mutant virus in T cells. The impaired fusion and infectivity of L49D mutant particles were also complemented by a single point mutation in the gp41 CT that disrupted the tyrosine-containing endocytic motif. Our results suggest that an altered interaction between the MA domain of Gag and the gp41 cytoplasmic tail leads to dissociation of gp120 from gp41 during HIV-1 particle assembly, thus resulting in impaired fusion and infectivity.
Collapse
Affiliation(s)
- Melody R Davis
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232-2363, USA
| | | | | | | | | |
Collapse
|
32
|
Affranchino JL, González SA. Mutations at the C-terminus of the simian immunodeficiency virus envelope glycoprotein affect gp120-gp41 stability on virions. Virology 2005; 347:217-25. [PMID: 16380144 DOI: 10.1016/j.virol.2005.11.032] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Revised: 10/27/2005] [Accepted: 11/22/2005] [Indexed: 11/21/2022]
Abstract
The transmembrane (TM) subunit of the envelope (Env) glycoprotein of the simian immunodeficiency virus (SIV) contains an unusually long cytoplasmic domain of 164 amino acids. Previously, we identified domains in the SIV TM cytoplasmic tail that are necessary for Env incorporation into virions and viral infectivity. In this study, we investigated the relevance to Env function of the highly conserved sequence comprising the immediate C-terminal 19 residues of TM. To this end, small in-frame deletions as well as a premature stop codon mutation were introduced into the coding region for the SIV TM C-terminus. All the mutant Env glycoproteins were expressed, processed and transported to the cell surface in an essentially wild-type manner. Moreover, the ability of the mutant Env proteins to mediate cell-to-cell fusion was similar to or slightly lower than that of the wild-type Env. However, viruses expressing the mutant Env glycoproteins were found to be poorly infectious in single-cycle infectivity assays. Further characterization of the TM mutant viruses revealed that while exhibiting wild-type levels of the TM protein, they contained significantly lower levels of the Env surface (SU) subunit, which is consistent with increased SU shedding from virions after Env incorporation. This phenotype was independent of Gag processing, since genetic inactivation of the viral protease did not increase SU retention by the resulting immature particles. Our findings indicate that deletions at the C-terminus of the SIV Env promote the instability of the SU-TM association on the virion surface and point to an important role for the TM cytoplasmic domain in modulating Env structure.
Collapse
Affiliation(s)
- José L Affranchino
- Centro de Virología Animal (CEVAN-CONICET), Serrano 669, C1414DEM Buenos Aires, Argentina
| | | |
Collapse
|
33
|
Hammonds J, Chen X, Fouts T, DeVico A, Montefiori D, Spearman P. Induction of neutralizing antibodies against human immunodeficiency virus type 1 primary isolates by Gag-Env pseudovirion immunization. J Virol 2005; 79:14804-14. [PMID: 16282480 PMCID: PMC1287556 DOI: 10.1128/jvi.79.23.14804-14814.2005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2005] [Accepted: 09/15/2005] [Indexed: 11/20/2022] Open
Abstract
A major challenge for the development of an effective HIV vaccine is to elicit neutralizing antibodies against a broad array of primary isolates. Monomeric gp120-based vaccine approaches have not been successful in inducing this type of response, prompting a number of approaches designed to recreate the native glycoprotein complex that exists on the viral membrane. Gag-Env pseudovirions are noninfectious viruslike particles that recreate the native envelope glycoprotein structure and have the potential to generate neutralizing antibody responses against primary isolates. In this study, an inducible cell line was created in order to generate Gag-Env pseudovirions for examination of neutralizing antibody responses in guinea pigs. Unadjuvanted pseudovirions generated relatively weak anti-gp120 responses, while the use of a block copolymer water-in-oil emulsion or aluminum hydroxide combined with CpG oligodeoxynucleotides resulted in high levels of antibodies that bind to gp120. Sera from immunized animals neutralized a panel of human immunodeficiency virus (HIV) type 1 primary isolate viruses at titers that were significantly higher than that of the corresponding monomeric gp120 protein. Interpretation of these results was complicated by the occurrence of neutralizing antibodies directed against cellular (non-envelope protein) components of the pseudovirion. However, a major component of the pseudovirion-elicited antibody response was directed specifically against the HIV envelope. These results provide support for the role of pseudovirion-based vaccines in generating neutralizing antibodies against primary isolates of HIV and highlight the potential confounding role of antibodies directed at non-envelope cell surface components.
Collapse
Affiliation(s)
- Jason Hammonds
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | | | | | | | | | | |
Collapse
|
34
|
Bachrach E, Dreja H, Lin YL, Mettling C, Pinet V, Corbeau P, Piechaczyk M. Effects of virion surface gp120 density on infection by HIV-1 and viral production by infected cells. Virology 2005; 332:418-29. [PMID: 15661172 DOI: 10.1016/j.virol.2004.11.031] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Revised: 10/29/2004] [Accepted: 11/23/2004] [Indexed: 11/29/2022]
Abstract
The quantity of envelope glycoprotein molecules (Env) on HIV-1 particles is still an issue of debate and, depending on the strain of virus and the nature of the producer cells, it can vary greatly. Here, we have attempted to address how Env density influences HIV-1 fitness. To this aim, we have produced HIV-1-derived viral particles with various amounts of R5 Env (low Env: Envlo; high Env: Envhi), using a regulatable expression system. The infectivity was assayed on human cells, engineered to express the HIV receptor CD4 and the co-receptor CCR5, as well as on peripheral blood lymphocytes and macrophages. In these experiments, low levels of Env were sufficient for cell infection, albeit at low efficiency. Increasing the amount of Env resulted in cooperatively improved infectivity, but a threshold was rapidly attained, indicating that only a fraction of Env was required for efficient infection. Unexpectedly, Env incorporation beyond what gives maximal infection transiently stimulated the expression of proviral genes, as well as retrovirus production, in newly infected cells. This was likely a consequence of induced NF-kappaB activity, as this transcription factor is triggered by Envhi, but not by Envlo, virions. Thus, our data suggest that one major effect of high Env density on the surface of HIV may not be better infection yields but rather improved viral production by newly infected cells.
Collapse
Affiliation(s)
- Estanislao Bachrach
- Institute of Molecular Genetics of Montpellier (IGMM)/UMR 5535/IFR24, CNRS, 1919 Route de Mende, 34293 Montpellier Cédex 05, France
| | | | | | | | | | | | | |
Collapse
|
35
|
Malkevitch NV, Robert-Guroff M. A call for replicating vector prime-protein boost strategies in HIV vaccine design. Expert Rev Vaccines 2005; 3:S105-17. [PMID: 15285710 DOI: 10.1586/14760584.3.4.s105] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A key challenge to HIV vaccine development is the integration of HIV proviral DNA into the host genome upon infection. Therefore, an optimal vaccine should block infection within hours of viral exposure, providing 'sterilizing immunity' at mucosal sites and in blood via potent, broadly reactive antibody to the HIV envelope glycoprotein. This is difficult due to the envelope's conformational complexity and sequence diversity. Antibodies that do not completely prevent infection nevertheless could reduce the viral infectious burden, allowing strong cellular immunity to control viremia, delay disease progression and prevent viral transmission, while also providing help for T- and B-cell responses. Rapidly responsive, potent, persistent immunity might best be achieved using prime-boost strategies incorporating a replicating vector and an optimally designed envelope subunit.
Collapse
Affiliation(s)
- Nina V Malkevitch
- Section on Immune Biology of Retroviral Infection, Vaccine Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892 5065, USA.
| | | |
Collapse
|
36
|
Young KR, Smith JM, Ross TM. Characterization of a DNA vaccine expressing a human immunodeficiency virus-like particle. Virology 2004; 327:262-72. [PMID: 15351214 DOI: 10.1016/j.virol.2004.07.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2004] [Revised: 06/14/2004] [Accepted: 07/12/2004] [Indexed: 11/17/2022]
Abstract
An ideal human immunodeficiency virus type-1 (HIV-1) vaccine will most likely need to elicit cross-reactive neutralizing antibodies and a strong cell-mediated immune response against multiple HIV-1 antigens to confer protection against challenge. In this study, DNA vaccines were constructed to express virally regulated human immunodeficiency virus-like particles (VLP) to elicit broad-spectrum immune responses to multiple HIV-1 antigens. VLPs were efficiently produced using sequences encoding gag and pol gene products from an X4 isolate and sequences encoding for tat, rev, vpu, and env from R5 or R5X4 isolates. The integrase, vpr, vif, and nef genes were deleted. In addition, the long terminal repeats (LTRs) were removed and transcription of the VLP insert was driven by the addition of the cytomegalovirus immediate-early (CMV-IE) promoter. A second generation of VLP vaccine plasmids was constructed with mutations engineered into the VLP DNA to produce particles deficient in activities associated with viral reverse transcriptase and protease. Primate cell lines, transiently transfected with DNA, efficiently secreted VLP into the supernatant that banded within a sucrose gradient at densities similar to infectious virions. In addition, these particles incorporated Env on the particle surface that bound soluble human CD4. These VLPs provide a safe and efficient strategy for presenting multiple HIV-1 antigens, expressed from a single insert, to the immune system in a structure that mimics the infectious virion.
Collapse
Affiliation(s)
- Kelly R Young
- Division of Infectious Diseases, Department of Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | | | | |
Collapse
|