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Kaur A, Vaccari M. Exploring HIV Vaccine Progress in the Pre-Clinical and Clinical Setting: From History to Future Prospects. Viruses 2024; 16:368. [PMID: 38543734 PMCID: PMC10974975 DOI: 10.3390/v16030368] [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: 01/09/2024] [Revised: 02/08/2024] [Accepted: 02/21/2024] [Indexed: 04/01/2024] Open
Abstract
The human immunodeficiency virus (HIV) continues to pose a significant global health challenge, with millions of people affected and new cases emerging each year. While various treatment and prevention methods exist, including antiretroviral therapy and non-vaccine approaches, developing an effective vaccine remains the most crucial and cost-effective solution to combating the HIV epidemic. Despite significant advancements in HIV research, the HIV vaccine field has faced numerous challenges, and only one clinical trial has demonstrated a modest level of efficacy. This review delves into the history of HIV vaccines and the current efforts in HIV prevention, emphasizing pre-clinical vaccine development using the non-human primate model (NHP) of HIV infection. NHP models offer valuable insights into potential preventive strategies for combating HIV, and they play a vital role in informing and guiding the development of novel vaccine candidates before they can proceed to human clinical trials.
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Affiliation(s)
- Amitinder Kaur
- Division of Immunology, Tulane National Primate Research Center, Covington, LA 70433, USA;
- School of Medicine, Tulane University, New Orleans, LA 70112, USA
| | - Monica Vaccari
- Division of Immunology, Tulane National Primate Research Center, Covington, LA 70433, USA;
- School of Medicine, Tulane University, New Orleans, LA 70112, USA
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2
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Rao PG, Lambert GS, Upadhyay C. Broadly neutralizing antibody epitopes on HIV-1 particles are exposed after virus interaction with host cells. J Virol 2023; 97:e0071023. [PMID: 37681958 PMCID: PMC10537810 DOI: 10.1128/jvi.00710-23] [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: 05/12/2023] [Accepted: 07/07/2023] [Indexed: 09/09/2023] Open
Abstract
The envelope (Env) glycoproteins on HIV-1 virions are the sole target of broadly neutralizing antibodies (bNAbs) and the focus of vaccines. However, many cross-reactive conserved epitopes are often occluded on virus particles, contributing to the evasion of humoral immunity. This study aimed to identify the Env epitopes that are exposed/occluded on HIV-1 particles and to investigate the mechanisms contributing to their masking. Using a flow cytometry-based assay, three HIV-1 isolates, and a panel of antibodies, we show that only select epitopes, including V2i, the gp120-g41 interface, and gp41-MPER, are accessible on HIV-1 particles, while V3, V2q, and select CD4bs epitopes are masked. These epitopes become accessible after allosteric conformational changes are induced by the pre-binding of select Abs, prompting us to test if similar conformational changes are required for these Abs to exhibit their neutralization capability. We tested HIV-1 neutralization where the virus-mAb mix was pre-incubated/not pre-incubated for 1 hour prior to adding the target cells. Similar levels of neutralization were observed under both assay conditions, suggesting that the interaction between virus and target cells sensitizes the virions for neutralization via bNAbs. We further show that lectin-glycan interactions can also expose these epitopes. However, this effect is dependent on the lectin specificity. Given that, bNAbs are ideal for providing sterilizing immunity and are the goal of current HIV-1 vaccine efforts, these data offer insight on how HIV-1 may occlude these vulnerable epitopes from the host immune response. In addition, the findings can guide the formulation of effective antibody combinations for therapeutic use. IMPORTANCE The human immunodeficiency virus (HIV-1) envelope (Env) glycoprotein mediates viral entry and is the sole target of neutralizing antibodies. Our data suggest that antibody epitopes including V2q (e.g., PG9, PGT145), CD4bs (e.g., VRC01, 3BNC117), and V3 (2219, 2557) are masked on HIV-1 particles. The PG9 and 2219 epitopes became accessible for binding after conformational unmasking was induced by the pre-binding of select mAbs. Attempts to understand the masking mechanism led to the revelation that interaction between virus and host cells is needed to sensitize the virions for neutralization by broadly neutralizing antibodies (bNAbs). These data provide insight on how bNAbs may gain access to these occluded epitopes to exert their neutralization effects and block HIV-1 infection. These findings have important implications for the way we evaluate the neutralizing efficacy of antibodies and can potentially guide vaccine design.
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Affiliation(s)
- Priyanka Gadam Rao
- Division of Infectious Disease, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Gregory S. Lambert
- Division of Infectious Disease, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Chitra Upadhyay
- Division of Infectious Disease, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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3
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Rao PG, Lambert GS, Upadhyay C. Broadly Neutralizing Antibody Epitopes on HIV-1 Particles are exposed after Virus Interaction with Host Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.20.524996. [PMID: 36711466 PMCID: PMC9882293 DOI: 10.1101/2023.01.20.524996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The envelope glycoproteins (Env) on HIV-1 virions are the sole target of broadly neutralizing antibodies (bNAb) and the focus of vaccines. However, many cross-reactive conserved epitopes are often occluded on virus particles, contributing to the evasion of humoral immunity. This study aimed to identify the Env epitopes that are exposed/occluded on HIV-1 particles and to investigate the mechanisms contributing to their masking. Using a flow cytometry-based assay, three HIV-1 isolates, and a panel of antibodies, we show that only select epitopes including V2i, gp120-g41 interface, and gp41-MPER are accessible on HIV-1 particles, while V3, V2q, and select CD4bs epitopes are masked. These epitopes become accessible after allosteric conformational changes are induced by pre-binding of select Abs, prompting us to test if similar conformational changes are required for these Abs to exhibit their neutralization capability. We tested HIV-1 neutralization where virus-mAb mix was pre-incubated/not pre-incubated for one hour prior to adding the target cells. Similar levels of neutralization were observed under both assay conditions, suggesting that the interaction between virus and target cells sensitizes the virions for neutralization via bNAbs. We further show that lectin-glycan interactions can also expose these epitopes. However, this effect is dependent on the lectin specificity. Given that, bNAbs are the ideal for providing sterilizing immunity and are the goal of current HIV-1 vaccine efforts, these data offer insight on how HIV-1 may occlude these vulnerable epitopes from the host immune response. In addition, the findings can guide the formulation of effective antibody combinations for therapeutic use.
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Horvath A, Rogers L, Pollakis G, Baranov O, Pieroth N, Joseph S, Chachage M, Heitzer A, Maganga L, Msafiri F, Joachim A, Viegas E, Eller LA, Kibuuka H, Rerks-Ngarm S, Pitisuttithum P, Nitayapan S, Dhitavat J, Premsri N, Fidler S, Shattock RJ, Robb ML, Weber J, McCormack S, Munseri PJ, Lyamuya E, Nilsson C, Kroidl A, Hoelscher M, Wagner R, Geldmacher C, Held K. Systematic comparison of HIV-1 Envelope-specific IgG responses induced by different vaccination regimens: Can we steer IgG recognition towards regions of viral vulnerability? Front Immunol 2022; 13:1075606. [PMID: 36741409 PMCID: PMC9891136 DOI: 10.3389/fimmu.2022.1075606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 12/16/2022] [Indexed: 01/11/2023] Open
Abstract
Immunogens and vaccination regimens can influence patterns of immune-epitope recognition, steering them towards or away from epitopes of potential viral vulnerability. HIV-1 envelope (Env)-specific antibodies targeting variable region 2 (V2) or 3 (V3) correlated with protection during the RV144 trial, however, it was suggested that the immunodominant V3 region might divert antibody responses away from other relevant sites. We mapped IgG responses against linear Env epitopes in five clinical HIV vaccine trials, revealing a specific pattern of Env targeting for each regimen. Notable V2 responses were only induced in trials administering CRF01_AE based immunogens, but targeting of V3 was seen in all trials, with the soluble, trimeric CN54gp140 protein eliciting robust V3 recognition. Strong V3 targeting was linked to greater overall response, increased number of total recognised antigenic regions, and where present, stronger V2 recognition. Hence, strong induction of V3-specific antibodies did not negatively impact the targeting of other linear epitopes in this study, suggesting that the induction of antibodies against V3 and other regions of potential viral vulnerability need not be necessarily mutually exclusive.
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Affiliation(s)
- Augusta Horvath
- Division of Infectious Diseases and Tropical Medicine, University Hospital, LMU Munich, Munich, Germany.,German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany
| | - Lisa Rogers
- Division of Infectious Diseases and Tropical Medicine, University Hospital, LMU Munich, Munich, Germany.,German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany
| | - Georgios Pollakis
- Institute of Infection Veterinary and Ecological Sciences (IVES/CIMI), University of Liverpool, Liverpool, United Kingdom
| | - Olga Baranov
- Division of Infectious Diseases and Tropical Medicine, University Hospital, LMU Munich, Munich, Germany.,German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany
| | - Nora Pieroth
- Division of Infectious Diseases and Tropical Medicine, University Hospital, LMU Munich, Munich, Germany.,German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany
| | - Sarah Joseph
- MRC Clinical Trials Unit at UCL, Institute of Clinical Trials and Methodology, University College London, London, United Kingdom
| | - Mkunde Chachage
- National Institute for Medical Research-Mbeya Medical Research Centre (NIMR-MMRC), Mbeya, Tanzania
| | - Asli Heitzer
- Division of Infectious Diseases and Tropical Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Lucas Maganga
- National Institute for Medical Research-Mbeya Medical Research Centre (NIMR-MMRC), Mbeya, Tanzania
| | - Frank Msafiri
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Agricola Joachim
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Edna Viegas
- Instituto Nacional de Saúde, Maputo, Mozambique
| | - Leigh-Anne Eller
- United States Military HIV Research Program, Silver Spring, MD, United States.,Makerere University Walter Reed Project, Kampala, Uganda.,Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States
| | - Hannah Kibuuka
- Makerere University Walter Reed Project, Kampala, Uganda
| | - Supachai Rerks-Ngarm
- Department of Disease Control, Ministry of Public Health, Mueang Nonthaburi, Thailand
| | | | | | - Jittima Dhitavat
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nakorn Premsri
- Department of Disease Control, Ministry of Public Health, Mueang Nonthaburi, Thailand
| | - Sarah Fidler
- Department of Medicine, Imperial College London, London, United Kingdom
| | - Robin J Shattock
- Department of Medicine, Imperial College London, London, United Kingdom
| | - Merlin Lee Robb
- United States Military HIV Research Program, Silver Spring, MD, United States.,Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States
| | - Jonathan Weber
- Department of Medicine, Imperial College London, London, United Kingdom
| | - Sheena McCormack
- MRC Clinical Trials Unit at UCL, Institute of Clinical Trials and Methodology, University College London, London, United Kingdom
| | | | - Eligius Lyamuya
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Charlotta Nilsson
- Department of Laboratory Medicine, Karolinska Institute, Huddinge, Sweden.,The Public Health Agency of Sweden, Solna, Sweden
| | - Arne Kroidl
- Division of Infectious Diseases and Tropical Medicine, University Hospital, LMU Munich, Munich, Germany.,German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany
| | - Michael Hoelscher
- Division of Infectious Diseases and Tropical Medicine, University Hospital, LMU Munich, Munich, Germany.,German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany
| | - Ralf Wagner
- Institute of Medical Microbiology and Hygiene, University Regensburg, Regensburg, Germany.,Institute of Clinical Microbiology and Hygiene; University Hospital Regensburg, Regensburg, Germany
| | - Christof Geldmacher
- Division of Infectious Diseases and Tropical Medicine, University Hospital, LMU Munich, Munich, Germany.,German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany
| | - Kathrin Held
- Division of Infectious Diseases and Tropical Medicine, University Hospital, LMU Munich, Munich, Germany.,German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany
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5
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Sherburn R, Tolbert WD, Gottumukkala S, Beaudoin-Bussières G, Finzi A, Pazgier M. Effects of gp120 Inner Domain (ID2) Immunogen Doses on Elicitation of Anti-HIV-1 Functional Fc-Effector Response to C1/C2 (Cluster A) Epitopes in Mice. Microorganisms 2020; 8:microorganisms8101490. [PMID: 32998443 PMCID: PMC7650682 DOI: 10.3390/microorganisms8101490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/21/2020] [Accepted: 09/23/2020] [Indexed: 01/13/2023] Open
Abstract
Fc-mediated effector functions of antibodies, including antibody-dependent cytotoxicity (ADCC), have been shown to contribute to vaccine-induced protection from HIV-1 infection, especially those directed against non-neutralizing, CD4 inducible (CD4i) epitopes within the gp120 constant 1 and 2 regions (C1/C2 or Cluster A epitopes). However, recent passive immunization studies have not been able to definitively confirm roles for these antibodies in HIV-1 prevention mostly due to the complications of cross-species Fc–FcR interactions and suboptimal dosing strategies. Here, we use our stabilized gp120 Inner domain (ID2) immunogen that displays the Cluster A epitopes within a minimal structural unit of HIV-1 Env to investigate an immunization protocol that induces a fine-tuned antibody repertoire capable of an effective Fc-effector response. This includes the generation of isotypes and the enhanced antibody specificity known to be vital for maximal Fc-effector activities, while minimizing the induction of isotypes know to be detrimental for these functions. Although our studies were done in in BALB/c mice we conclude that when optimally titrated for the species of interest, ID2 with GLA-SE adjuvant will elicit high titers of antibodies targeting the Cluster A region with potent Fc-mediated effector functions, making it a valuable immunogen candidate for testing an exclusive role of non-neutralizing antibody response in HIV-1 protection in vaccine settings.
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Affiliation(s)
- Rebekah Sherburn
- Infectious Disease Division, Department of Medicine of Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4712, USA; (R.S.); (W.D.T.); (S.G.)
| | - William D. Tolbert
- Infectious Disease Division, Department of Medicine of Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4712, USA; (R.S.); (W.D.T.); (S.G.)
| | - Suneetha Gottumukkala
- Infectious Disease Division, Department of Medicine of Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4712, USA; (R.S.); (W.D.T.); (S.G.)
| | | | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada; (G.B.-B.); (A.F.)
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H3C 3J7, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, QC H3A 2B4, Canada
| | - Marzena Pazgier
- Infectious Disease Division, Department of Medicine of Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4712, USA; (R.S.); (W.D.T.); (S.G.)
- Correspondence: ; Tel.: +301-295-3291; Fax: +301-295-355
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6
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Duerr R, Gorny MK. V2-Specific Antibodies in HIV-1 Vaccine Research and Natural Infection: Controllers or Surrogate Markers. Vaccines (Basel) 2019; 7:vaccines7030082. [PMID: 31390725 PMCID: PMC6789775 DOI: 10.3390/vaccines7030082] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 07/26/2019] [Accepted: 07/27/2019] [Indexed: 12/20/2022] Open
Abstract
Most human immunodeficiency virus (HIV) vaccine trials have lacked efficacy and empirical vaccine lead targets are scarce. Thus far, the only independent correlate of reduced risk of HIV-1 acquisition in humans is elevated levels of V2-specific antibodies identified in the modestly protective RV144 vaccine trial. Ten years after RV144, human and non-human primate vaccine studies have reassessed the potential contribution of V2-specific antibodies to vaccine efficacy. In addition, studies of natural HIV-1 infection in humans have provided insight into the development of V1V2-directed antibody responses and their impact on clinical parameters and disease progression. Functionally diverse anti-V2 monoclonal antibodies were isolated and their structurally distinct V2 epitope regions characterized. After RV144, a plethora of research studies were performed using different model systems, immunogens, protocols, and challenge viruses. These diverse studies failed to provide a clear picture regarding the contribution of V2 antibodies to vaccine efficacy. Here, we summarize the biological functions and clinical findings associated with V2-specific antibodies and discuss their impact on HIV vaccine research.
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Affiliation(s)
- Ralf Duerr
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA.
| | - Miroslaw K Gorny
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
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7
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Liu L, Li L, Nanfack A, Mayr LM, Soni S, Kohutnicki A, Agyingi L, Wang XH, Tuen M, Shao Y, Totrov M, Zolla-Pazner S, Kong XP, Duerr R, Gorny MK. Anti-V2 antibody deficiency in individuals infected with HIV-1 in Cameroon. Virology 2019; 529:57-64. [PMID: 30665098 DOI: 10.1016/j.virol.2019.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 01/09/2019] [Accepted: 01/11/2019] [Indexed: 02/07/2023]
Abstract
The results of the RV144 vaccine clinical trial showed a correlation between high level of anti-V1V2 antibodies (Abs) and a decreased risk of acquiring HIV-1 infection. This turned the focus of HIV vaccine design to the induction of elevated levels of anti-V2 Abs to increase vaccine efficacy. In plasma samples from HIV-1 infected Cameroonian individuals, we observed broad variations in levels of anti-V2 Abs, and 6 of the 79 plasma samples tested longitudinally displayed substantial deficiency of V2 Abs. Sequence analysis of the V2 region from plasma viruses and multivariate analyses of V2 characteristics showed a significant difference in several features between V2-deficient and V2-reactive plasma Abs. These results suggest that HIV vaccine immunogens containing a shorter V2 region with fewer glycosylation sites and higher electrostatic charges can be beneficial for induction of a higher level of anti-V2 Abs and thus contribute to HIV vaccine efficacy.
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Affiliation(s)
- Lily Liu
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | - Liuzhe Li
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | - Aubin Nanfack
- Medical Diagnostic Center, Yaoundé, Cameroon; Chantal Biya International Reference Center for Research on HIV/AIDS Prevention and Management, Yaoundé, Cameroon
| | - Luzia M Mayr
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | - Sonal Soni
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | - Adam Kohutnicki
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | - Lucy Agyingi
- Medical Diagnostic Center, Yaoundé, Cameroon; Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Xiao-Hong Wang
- Veterans Affairs New York Harbor Healthcare System, New York, NY, USA
| | - Michael Tuen
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | - Yongzhao Shao
- Population Health, New York University School of Medicine, New York, NY, USA
| | | | - Susan Zolla-Pazner
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Xian-Peng Kong
- Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Ralf Duerr
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | - Miroslaw K Gorny
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA.
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8
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Identification of Novel Structural Determinants in MW965 Env That Regulate the Neutralization Phenotype and Conformational Masking Potential of Primary HIV-1 Isolates. J Virol 2018; 92:JVI.01779-17. [PMID: 29237828 DOI: 10.1128/jvi.01779-17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 11/28/2017] [Indexed: 11/20/2022] Open
Abstract
The subtype C HIV-1 isolate MW965.26 is a highly neutralization-sensitive tier 1a primary isolate that is widely used in vaccine studies, but the basis for the sensitive neutralization phenotype of this isolate is not known. Substituting the MW965.26 V1/V2 domain into a neutralization-sensitive SF162 Env clone resulted in high resistance to standard anti-V3 monoclonal antibodies, demonstrating that this region possesses strong masking activity in a standard Env backbone and indicating that determinants elsewhere in MW965.26 Env are responsible for its unusual neutralization sensitivity. Key determinants for this phenotype were mapped by generating chimeric Envs between MW965.26 Env and a typical resistant Env clone, the consensus C (ConC) clone, and localized to two residues, Cys384 in the C3 domain and Asn502 in the C5 domain. Substituting the sensitizing mutations Y384C and K502N at these positions into several resistant primary Envs resulted in conversion to neutralization-sensitive phenotypes, demonstrating the generalizability of this effect. In contrast to the sensitizing effects of these substitutions on normally masked epitopes, these mutations reduced the sensitivity of VRC01-like epitopes overlapping the CD4-binding domain, while they had no effect on several other classes of broadly neutralizing epitopes, including members of several lineages of V2-dependent quaternary epitopes and representatives of N332 glycan-dependent epitopes (PGT121) and quaternary, cleavage-dependent epitopes centered at the gp41-gp120 interface on intact HIV-1 Env trimers (PGT151). These results identify novel substitutions in gp120 that regulate the expression of alternative conformations of Env and differentially affect the exposure of different classes of epitopes, thereby influencing the neutralization phenotype of primary HIV-1 isolates.IMPORTANCE A better understanding of the mechanisms that determine the wide range of neutralization sensitivity of circulating primary HIV-1 isolates would provide important information about the natural structural and conformational diversity of HIV-1 Env and how this affects the neutralization phenotype. A useful way of studying this is to determine the molecular basis for the unusually high neutralization sensitivities of the limited number of available tier 1a viruses. This study localized the neutralization sensitivity of MW965.26, an extremely sensitive subtype C-derived primary isolate, to two rare substitutions in the C3 and C5 domains and demonstrated that the sequences at these positions differentially affect the presentation of epitopes recognized by different classes of standard and conformation-dependent broadly neutralizing antibodies. These results provide novel insight into how these regions regulate the neutralization phenotype and provide tools for controlling the Env conformation that could have applications both for structural studies and in vaccine design.
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9
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Rationally Designed Immunogens Targeting HIV-1 gp120 V1V2 Induce Distinct Conformation-Specific Antibody Responses in Rabbits. J Virol 2016; 90:11007-11019. [PMID: 27707920 DOI: 10.1128/jvi.01409-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 09/23/2016] [Indexed: 11/20/2022] Open
Abstract
The V1V2 region of HIV-1 gp120 harbors a major vulnerable site targeted by a group of broadly neutralizing monoclonal antibodies (MAbs) such as PG9 through strand-strand recognition. However, this epitope region is structurally polymorphic as it can also form a helical conformation recognized by RV144 vaccine-induced MAb CH58. This structural polymorphism is a potential mechanism for masking the V1V2 vulnerable site. Designing immunogens that can induce conformation-specific antibody (Ab) responses may lead to vaccines targeting this vulnerable site. We designed a panel of immunogens engrafting the V1V2 domain into trimeric and pentameric scaffolds in structurally constrained conformations. We also fused V1V2 to an Fc fragment to mimic the unconstrained V1V2 conformation. We tested these V1V2-scaffold proteins for immunogenicity in rabbits and assessed the responses by enzyme-linked immunosorbent assay (ELISA) and competition assays. Our V1V2 immunogens induced distinct conformation-specific Ab responses. Abs induced by structurally unconstrained immunogens reacted preferentially with unconstrained V1V2 antigens, suggesting recognition of the helical configuration, while Abs induced by the structurally constrained immunogens reacted preferentially with constrained V1V2 antigens, suggesting recognition of the β-strand conformation. The Ab responses induced by the structurally constrained immunogens were more broadly reactive and had higher titers than those induced by the structurally unconstrained immunogens. Our results demonstrate that immunogens presenting the different structural conformations of the gp120 V1V2 vulnerable site can be designed and that these immunogens induce distinct Ab responses with epitope conformation specificity. Therefore, these structurally constrained V1V2 immunogens are vaccine prototypes targeting the V1V2 domain of the HIV-1 envelope. IMPORTANCE The correlates analysis of the RV144 HIV-1 vaccine trial suggested that the presence of antibodies to the V1V2 region of HIV-1 gp120 was responsible for the modest protection observed in the trial. In addition, V1V2 harbors one of the key vulnerable sites of HIV-1 Env recognized by a family of broadly neutralizing MAbs such as PG9. Thus, V1V2 is a key target for vaccine development. However, this vulnerable site is structurally polymorphic, and designing immunogens that present different conformations is crucial for targeting this site. We show here that such immunogens can be designed and that they induced conformation-specific antibody responses in rabbits. Our immunogens are therefore prototypes of vaccine candidates targeting the V1V2 region of HIV-1 Env.
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10
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Qin Y, Banerjee S, Agrawal A, Shi H, Banasik M, Lin F, Rohl K, LaBranche C, Montefiori DC, Cho MW. Characterization of a Large Panel of Rabbit Monoclonal Antibodies against HIV-1 gp120 and Isolation of Novel Neutralizing Antibodies against the V3 Loop. PLoS One 2015; 10:e0128823. [PMID: 26039641 PMCID: PMC4454676 DOI: 10.1371/journal.pone.0128823] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 04/30/2015] [Indexed: 01/05/2023] Open
Abstract
We recently reported the induction of potent, cross-clade neutralizing antibodies (nAbs) against Human Immunodeficiency Virus type-1 (HIV-1) in rabbits using gp120 based on an M-group consensus sequence. To better characterize these antibodies, 93 hybridomas were generated, which represent the largest panel of monoclonal antibodies (mAbs) ever generated from a vaccinated rabbit. The single most frequently recognized epitope of the isolated mAbs was at the very C-terminal end of the protein (APTKAKRRVVEREKR), followed by the V3 loop. A total of seven anti-V3 loop mAbs were isolated, two of which (10A3 and 10A37) exhibited neutralizing activity. In contrast to 10A3 and most other anti-V3 loop nAbs, 10A37 was atypical with its epitope positioned more towards the C-terminal half of the loop. To our knowledge, 10A37 is the most potent and broadly neutralizing anti-V3 loop mAb induced by vaccination. Interestingly, all seven anti-V3 loop mAbs competed with PGT121, suggesting a possibility that early induction of potent anti-V3 loop antibodies could prevent induction of more broadly neutralizing PGT121-like antibodies that target the conserved base of the V3 loop stem.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/biosynthesis
- Antibodies, Monoclonal/chemistry
- Antibodies, Monoclonal/isolation & purification
- Antibodies, Neutralizing/biosynthesis
- Antibodies, Neutralizing/chemistry
- Antibodies, Neutralizing/isolation & purification
- Binding Sites, Antibody
- Conserved Sequence
- Epitopes/chemistry
- Epitopes/immunology
- Female
- HIV Antibodies/biosynthesis
- HIV Antibodies/chemistry
- HIV Antibodies/isolation & purification
- HIV Envelope Protein gp120/administration & dosage
- HIV Envelope Protein gp120/chemistry
- HIV Envelope Protein gp120/immunology
- HIV-1/chemistry
- HIV-1/immunology
- Hybridomas/immunology
- Models, Molecular
- Molecular Sequence Data
- Neutralization Tests
- Protein Binding
- Protein Structure, Secondary
- Protein Structure, Tertiary
- Rabbits
- Vaccination
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Affiliation(s)
- Yali Qin
- Department of Biomedical Sciences, Iowa State University, Ames, IA, 50011, United States of America
- Center for Advanced Host Defenses, Immunobiotics and Translational Comparative Medicine, Iowa State University, Ames, IA, 50011, United States of America
| | - Saikat Banerjee
- Department of Biomedical Sciences, Iowa State University, Ames, IA, 50011, United States of America
- Center for Advanced Host Defenses, Immunobiotics and Translational Comparative Medicine, Iowa State University, Ames, IA, 50011, United States of America
| | - Aditi Agrawal
- Department of Biomedical Sciences, Iowa State University, Ames, IA, 50011, United States of America
- Center for Advanced Host Defenses, Immunobiotics and Translational Comparative Medicine, Iowa State University, Ames, IA, 50011, United States of America
| | - Heliang Shi
- Department of Biomedical Sciences, Iowa State University, Ames, IA, 50011, United States of America
- Center for Advanced Host Defenses, Immunobiotics and Translational Comparative Medicine, Iowa State University, Ames, IA, 50011, United States of America
| | - Marisa Banasik
- Department of Biomedical Sciences, Iowa State University, Ames, IA, 50011, United States of America
- Center for Advanced Host Defenses, Immunobiotics and Translational Comparative Medicine, Iowa State University, Ames, IA, 50011, United States of America
| | - Feng Lin
- Department of Biomedical Sciences, Iowa State University, Ames, IA, 50011, United States of America
- Center for Advanced Host Defenses, Immunobiotics and Translational Comparative Medicine, Iowa State University, Ames, IA, 50011, United States of America
| | - Kari Rohl
- Department of Biomedical Sciences, Iowa State University, Ames, IA, 50011, United States of America
- Center for Advanced Host Defenses, Immunobiotics and Translational Comparative Medicine, Iowa State University, Ames, IA, 50011, United States of America
| | - Celia LaBranche
- Department of Surgery, Duke University, Durham, NC, 27710, United States of America
| | - David C. Montefiori
- Department of Surgery, Duke University, Durham, NC, 27710, United States of America
| | - Michael W. Cho
- Department of Biomedical Sciences, Iowa State University, Ames, IA, 50011, United States of America
- Center for Advanced Host Defenses, Immunobiotics and Translational Comparative Medicine, Iowa State University, Ames, IA, 50011, United States of America
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11
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The V1V2 Region of HIV-1 gp120 Forms a Five-Stranded Beta Barrel. J Virol 2015; 89:8003-10. [PMID: 26018158 PMCID: PMC4505664 DOI: 10.1128/jvi.00754-15] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 05/16/2015] [Indexed: 01/07/2023] Open
Abstract
UNLABELLED The region consisting of the first and second variable regions (V1V2) of gp120 plays vital roles in the functioning of the HIV-1 envelope (Env). V1V2, which harbors multiple glycans and is highly sequence diverse, is located at the Env apex and stabilizes the trimeric gp120 spike on the virion surface. It shields V3 and the coreceptor binding sites in the prefusion state and exposes them upon CD4 binding. Data from the RV144 human HIV-1 vaccine trial suggested that antibody responses targeting the V1V2 region inversely correlated with the risk of infection; thus, understanding the antigenic structure of V1V2 can contribute to vaccine design. We have determined a crystal structure of a V1V2 scaffold molecule (V1V2ZM109-1FD6) in complex with 830A, a human monoclonal antibody that recognizes a V1V2 epitope overlapping the integrin-binding motif in V2. The structure revealed that V1V2 assumes a five-stranded beta barrel structure with the region of the integrin-binding site (amino acids [aa] 179 to 181) included in a "kink" followed by an extra beta strand. The complete barrel structure naturally presents the glycans on its outer surface and packs into its core conserved hydrophobic residues, including the Ile at position 181 which was highly correlated with vaccine efficacy in RV144. The epitope of monoclonal antibody 830A is discontinuous and composed of three segments: (i) Thr175, Tyr177, Leu179, and Asp180 at the kink overlapping the integrin-binding site; (ii) Arg153 and Val154 in V1; and (iii) Ile194 at the C terminus of V2. This report thus provides the atomic details of the immunogenic "V2i epitope." IMPORTANCE Data from the RV144 phase III clinical trial suggested that the presence of antibodies to the first and second variable regions (V1V2) of gp120 was associated with the modest protection afforded by the vaccine. V1V2 is a highly variable and immunogenic region of HIV-1 surface glycoprotein gp120, and structural information about this region and its antigenic landscape will be crucial in the design of an effective HIV-1 vaccine. We have determined a crystal structure of V1V2 in complex with human MAb 830A and have shown that MAb 830A recognizes a region overlapping the α4β7 integrin-binding site. We also showed that V1V2 forms a 5-stranded beta barrel, an elegant structure allowing sequence variations in the strand-connecting loops while preserving a conserved core.
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12
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Topological analysis of HIV-1 glycoproteins expressed in situ on virus surfaces reveals tighter packing but greater conformational flexibility than for soluble gp120. J Virol 2013; 87:9233-49. [PMID: 23740975 DOI: 10.1128/jvi.01145-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In natural infection, antibodies interact with HIV-1 primarily through nonfunctional forms of envelope glycoproteins (Env), including uncleaved (UNC) gp160 and gp41 stumps. These antigens are important to fully characterize, as they may be decoys that promote nonneutralizing responses and may also be targets for nonneutralizing effector responses. In this study, we compared the antigenic properties of Env expressed in situ on pseudovirion virus-like particle (VLP) surfaces and soluble gp120 using harmonized enzyme-linked immunosorbent assays (ELISAs) and a panel of 51 monoclonal antibodies (MAbs). Only 32 of 46 soluble gp120-reactive MAbs recognized the primary UNC gp160 antigen of VLPs. Indeed, many epitopes were poorly exposed (C1, V2, C1-C4, C4, C4-V3, CD4 induced [CD4i], and PGT group 3) or obscured (C2, C5, and C1-C5) on VLPs. In further studies, VLP Env exhibited an increased degree of inter-MAb competition, the epicenter of which was the base of the V3 loop, where PGT, 2G12, V3, and CD4 binding site specificities competed. UNC gp160 also underwent more drastic soluble CD4 (sCD4)-induced conformational changes than soluble gp120, exposing CD4i, C1-C4, and V2 epitopes. A greater propensity of UNC gp160 to undergo conformational changes was also suggested by the induction of CD4i MAb binding to VLPs by a V3 MAb as well as by soluble CD4. The same effect was not observed for soluble gp120. Taken together, our data suggest that membrane-expressed UNC gp160 exists in a less "triggered" conformational state than soluble gp120 and that MAb binding to UNC gp160 tends to have greater conformational consequences.
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13
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Moore PL, Sheward D, Nonyane M, Ranchobe N, Hermanus T, Gray ES, Abdool Karim SS, Williamson C, Morris L. Multiple pathways of escape from HIV broadly cross-neutralizing V2-dependent antibodies. J Virol 2013; 87:4882-94. [PMID: 23408621 PMCID: PMC3624332 DOI: 10.1128/jvi.03424-12] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 02/06/2013] [Indexed: 11/20/2022] Open
Abstract
Broadly cross-neutralizing (BCN) antibodies are likely to be critical for an effective HIV vaccine. However, the ontogeny of such antibodies and their relationship with autologous viral evolution is unclear. Here, we characterized viral evolution in CAP256, a subtype C-infected individual who developed potent BCN antibodies targeting positions R166 and K169 in the V2 region. CAP256 was superinfected at 3 months postinfection with a virus that was highly sensitive to BCN V2-dependent monoclonal antibodies. The autologous neutralizing response in CAP256 was directed at V1V2, reaching extremely high titers (>1:40,000) against the superinfecting virus at 42 weeks, just 11 weeks prior to the development of the BCN response targeting the same region. Recombination between the primary and superinfecting viruses, especially in V2 and gp41, resulted in two distinct lineages by 4 years postinfection. Although neutralization of some CAP256 clones by plasma from as much as 2 years earlier suggested incomplete viral escape, nonetheless titers against later clones were reduced at least 40-fold to less than 1:1,000. Escape mutations were identified in each lineage, either at R166 or at K169, suggesting that strain-specific and BCN antibodies targeted overlapping epitopes. Furthermore, the early dependence of CAP256 neutralizing antibodies on the N160 glycan decreased with the onset of neutralization breadth, indicating a change in specificity. These data suggest rapid maturation, within 11 weeks, of CAP256 strain-specific antibodies to acquire breadth, with implications for the vaccine elicitation of BCN V2-dependent antibodies. Overall these studies demonstrate that ongoing viral escape is possible, even from BCN antibodies.
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Affiliation(s)
- Penny L Moore
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Services, Johannesburg, South Africa.
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14
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Structure-function relationships of HIV-1 envelope sequence-variable regions refocus vaccine design. Nat Rev Immunol 2010; 10:527-35. [PMID: 20577269 DOI: 10.1038/nri2801] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
One of the main challenges of developing an HIV-1 vaccine lies in eliciting immune responses that can overcome the antigenic variability exhibited by HIV. Most HIV-1 vaccine development has focused on inducing immunity to conserved regions of the HIV-1 envelope. However, new studies of the sequence-variable regions of the HIV-1 gp120 envelope glycoprotein have shown that there are conserved immunological and structural features in these regions. Recombinant immunogens that include these features may provide the means to address the antigenic diversity of HIV-1 and induce protective antibodies that can prevent infection with HIV-1.
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15
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Papandréou MJ, Barbouche R, Guieu R, Rivera S, Fantini J, Khrestchatisky M, Jones IM, Fenouillet E. Mapping of domains on HIV envelope protein mediating association with calnexin and protein-disulfide isomerase. J Biol Chem 2010; 285:13788-96. [PMID: 20202930 DOI: 10.1074/jbc.m109.066670] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The cell catalysts calnexin (CNX) and protein-disulfide isomerase (PDI) cooperate in establishing the disulfide bonding of the HIV envelope (Env) glycoprotein. Following HIV binding to lymphocytes, cell-surface PDI also reduces Env to induce the fusogenic conformation. We sought to define the contact points between Env and these catalysts to illustrate their potential as therapeutic targets. In lysates of Env-expressing cells, 15% of the gp160 precursor, but not gp120, coprecipitated with CNX, whereas only 0.25% of gp160 and gp120 coprecipitated with PDI. Under in vitro conditions, which mimic the Env/PDI interaction during virus/cell contact, PDI readily associated with Env. The domains of Env interacting in cellulo with CNX or in vitro with PDI were then determined using anti-Env antibodies whose binding site was occluded by CNX or PDI. Antibodies against domains V1/V2, C2, and the C terminus of V3 did not bind CNX-associated Env, whereas those against C1, V1/V2, and the CD4-binding domain did not react with PDI-associated Env. In addition, a mixture of the latter antibodies interfered with PDI-mediated Env reduction. Thus, Env interacts with intracellular CNX and extracellular PDI via discrete, largely nonoverlapping, regions. The sites of interaction explain the mode of action of compounds that target these two catalysts and may enable the design of further new competitive agents.
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16
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Dosenovic P, Chakrabarti B, Soldemo M, Douagi I, Forsell MNE, Li Y, Phogat A, Paulie S, Hoxie J, Wyatt RT, Karlsson Hedestam GB. Selective expansion of HIV-1 envelope glycoprotein-specific B cell subsets recognizing distinct structural elements following immunization. THE JOURNAL OF IMMUNOLOGY 2009; 183:3373-82. [PMID: 19696434 DOI: 10.4049/jimmunol.0900407] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The HIV-1 envelope glycoprotein (Env) functional spike has evolved multiple immune evasion strategies, and only a few broadly neutralizing determinants on the assembled spike are accessible to Abs. Serological studies, based upon Ab binding and neutralization activity in vitro, suggest that vaccination with current Env-based immunogens predominantly elicits Abs that bind nonneutralizing or strain-restricted neutralizing epitopes. However, the fractional specificities of the polyclonal mixture of Abs present in serum, especially those directed to conformational Env epitopes, are often difficult to determine. Furthermore, serological analyses do not provide information regarding how repeated Ag inoculation impacts the expansion and maintenance of Env-specific B cell subpopulations. Therefore, we developed a highly sensitive Env-specific B cell ELISPOT system, which allows the enumeration of Ab-secreting cells (ASC) from diverse anatomical compartments directed against different structural determinants of Env. In this study, we use this system to examine the evolution of B cell responses in mice immunized with engineered Env trimers in adjuvant. We demonstrate that the relative proportion of ASC specific for defined structural elements of Env is altered significantly by homologous booster immunizations. This results in the selective expansion of ASC directed against the variable regions of Env. We suggest that the B cell specificity and compartment analysis described in this study are important complements to serological mapping studies for the examination of B cell responses against subspecificities of a variety of immunogens.
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Affiliation(s)
- Pia Dosenovic
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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17
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Granados-Gonzalez V, Claret J, Berlier W, Vincent N, Urcuqui-Inchima S, Lucht F, Defontaine C, Pinter A, Genin C, Riffard S. Opposite immune reactivity of serum IgG and secretory IgA to conformational recombinant proteins mimicking V1/V2 domains of three different HIV type 1 subtypes depending on glycosylation. AIDS Res Hum Retroviruses 2008; 24:289-99. [PMID: 18260782 DOI: 10.1089/aid.2007.0187] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The V1/V2 domain of the HIV-1 gp120 envelope protein has been shown to contribute to viral cell tropism during infection and also to viral recognition by neutralizing monoclonal antibodies. However, this domain has been poorly investigated. Carbohydrates have been demonstrated to dramatically influence immune reactivity of antisera to viral glycoprotein antigens. In this study, DNA sequences coding for V1/V2 domains from HIV-1 primary isolates of three subtypes (A, B, and C) were subcloned into a secretion vector and used to transfect CHO cells that are able to achieve the glycosylation of proteins. The structure of purified recombinant V1/V2 proteins was tested using two anti-V1/V2 monoclonal antibodies directed against either a linear or a conformational and glycosylation-dependent epitope (8.22.2 and 697-D). Serum or saliva of 14/82 seropositive patients with anti-V1/V2 reactivity demonstrated good recognition of the recombinant proteins. Deglycosylation of the recombinant proteins was found to increase the reactivity of the serum IgG to the clade A and C but not to clade B V1/V2 domain demonstrating that the recognition of glycosylation sites by serum IgG is clade dependent. When considering SIgA from parotid saliva, deglycosylation of all recombinant proteins tested decreased the reactivity, suggesting that glycosylation plays an important role in the recognition of V1/V2 domain target epitopes by this class of antibodies. In conclusion, these results suggest the influence of carbohydrate moieties on the specificity of the antibodies to the V1/V2 domain produced during HIV infection and the potential importance of viral glycans in vaccine responses after mucosal administration.
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Affiliation(s)
- Viviana Granados-Gonzalez
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Julien Claret
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Willy Berlier
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Nadine Vincent
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | | | - Frederic Lucht
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Christiane Defontaine
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Abraham Pinter
- Laboratory of Retroviral Virology, Public Health Research Institute, Newark, New Jersey
| | - Christian Genin
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Serge Riffard
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
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18
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Honnen WJ, Krachmarov C, Kayman SC, Gorny MK, Zolla-Pazner S, Pinter A. Type-specific epitopes targeted by monoclonal antibodies with exceptionally potent neutralizing activities for selected strains of human immunodeficiency virus type 1 map to a common region of the V2 domain of gp120 and differ only at single positions from the clade B consensus sequence. J Virol 2006; 81:1424-32. [PMID: 17121806 PMCID: PMC1797533 DOI: 10.1128/jvi.02054-06] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Only a few monoclonal antibodies (MAbs) have been isolated that recognize conserved sites in human immunodeficiency virus type 1 (HIV-1) Env proteins and possess broad neutralizing activities. Other MAbs directed against targets in various domains of Env have been described that are strongly neutralizing, but they possess limited breadth. One such MAb, 2909, possesses a uniquely potent neutralizing activity specific for a quaternary epitope on SF162 Env that requires the presence of both the V2 and the V3 domains. We now show that replacement of the SF162 V3 sequence with consensus V3 sequences of multiple subtypes led to attenuated but still potent neutralization by 2909 and that the main determinants for the type specificity of 2909 reside in the V2 domain. A substitution at position 160 completely eliminated 2909 reactivity, and mutations at position 167 either attenuated or potentiated neutralization by this antibody. Different substitutions at the same positions in V2 were previously shown to introduce epitopes recognized by MAbs 10/76b and C108g and to allow potent neutralization by these MAbs. Two substitutions at key positions in the V2 domain of JR-FL Env also allowed potent expression of the 2909 epitope, and single substitutions in YU2 V2 were sufficient for expression of the 2909, C108g, and 10/76b epitopes. These results demonstrate that the minimal epitopes for 2909, C108g, and 10/76b differed from that of the clade B consensus sequence only at single positions and suggest that all three MAbs recognize distinct variants of a relatively conserved sequence in V2 that is a particularly sensitive mediator of HIV-1 neutralization.
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Affiliation(s)
- W J Honnen
- Public Health Research Institute, UMDNJ, 255 Warren Street, Newark, NJ 07103-3535, USA
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19
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Toellner L, Fischlechner M, Ferko B, Grabherr RM, Donath E. Virus-coated layer-by-layer colloids as a multiplex suspension array for the detection and quantification of virus-specific antibodies. Clin Chem 2006; 52:1575-83. [PMID: 16728470 DOI: 10.1373/clinchem.2005.065789] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Suspension array technology has surpassed ELISA for automated, simultaneous detection and quantification of soluble biomarkers such as virus-specific antibodies. We describe assays in which antigens are attached to a lipid bilayer surrounding color-coded particles. METHODS We used layer-by-layer technology to establish a multiplex suspension array with distinguishable microbeads coated with authentic viral surfaces to catch and quantify virus-specific antibodies in a flow cytometric analysis. Antigenic surfaces were generated by chimeric and wild-type baculoviruses plus 2 different influenza A virus subtypes fused to a lipid bilayer surrounding distinctly colored particles. Specificity of binding of chosen antibodies and sera was detected by immunofluorescence. Results of multiplex analysis were compared with results of ELISA. RESULTS Titrations of virus-specific antibodies in the multiplex suspension array demonstrated specific binding to the viral surface proteins. The multiplex suspension array gave positive results for up to log 5-diluted primary antibodies with an approximately 5- to 10-fold reduced dynamic range compared with the respective ELISA. CONCLUSIONS The bead-based multiplex suspension array is customizable and easy to establish. By displaying native influenza A virus surfaces and recombinant HIV-1 epitopes, the new assay provides a tool for the detection of major viral infections in humans.
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Affiliation(s)
- Lars Toellner
- Institute of Medical Physics and Biophysics, Leipzig University, Leipzig, Germany
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20
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Fischlechner M, Toellner L, Messner P, Grabherr R, Donath E. Virus-Engineered Colloidal Particles—A Surface Display System. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200502620] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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21
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Fischlechner M, Toellner L, Messner P, Grabherr R, Donath E. Virus-engineered colloidal particles--a surface display system. Angew Chem Int Ed Engl 2006; 45:784-9. [PMID: 16355425 PMCID: PMC4379499 DOI: 10.1002/anie.200502620] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Martin Fischlechner
- Institute of Medical Physics and Biophysics, Leipzig University, Härtelstrasse 16–18, 04107 Leipzig (Germany)
| | - Lars Toellner
- Institute of Medical Physics and Biophysics, Leipzig University, Härtelstrasse 16–18, 04107 Leipzig (Germany)
| | - Paul Messner
- Center for NanoBiotechnology, University of Natural Resources and Applied Life Sciences, 1180 Vienna (Austria)
| | - Reingard Grabherr
- Institute of Applied Microbiology, University of Natural Resources and Applied Life Sciences, 1190 Vienna (Austria)
| | - Edwin Donath
- Institute of Medical Physics and Biophysics, Leipzig University, Härtelstrasse 16–18, 04107 Leipzig (Germany)
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22
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Dey AK, Khati M, Tang M, Wyatt R, Lea SM, James W. An aptamer that neutralizes R5 strains of human immunodeficiency virus type 1 blocks gp120-CCR5 interaction. J Virol 2005; 79:13806-10. [PMID: 16227301 PMCID: PMC1262572 DOI: 10.1128/jvi.79.21.13806-13810.2005] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We recently described the isolation and structural characterization of 2'-fluoropyrimidine-substituted RNA aptamers that bind to gp120 of R5 strains of human immunodeficiency virus type 1 and thereby potently neutralize the infectivity of phylogenetically diverse R5 strains. Here we investigate the physical basis of their antiviral action. We show that both N-linked oligosaccharides and the variable loops V1/V2 and V3 are not required for binding of one aptamer, B40, to gp120. Using surface plasmon resonance binding analyses, we show that the aptamer binds to the CCR5-binding site on gp120 in a relatively CD4-independent manner, providing a mechanistic explanation for its neutralizing potency.
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Affiliation(s)
- Antu K Dey
- Laboratory of Molecular Biophysics, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, United Kingdom
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23
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Pinter A, Honnen WJ, D'Agostino P, Gorny MK, Zolla-Pazner S, Kayman SC. The C108g epitope in the V2 domain of gp120 functions as a potent neutralization target when introduced into envelope proteins derived from human immunodeficiency virus type 1 primary isolates. J Virol 2005; 79:6909-17. [PMID: 15890930 PMCID: PMC1112130 DOI: 10.1128/jvi.79.11.6909-6917.2005] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Monoclonal antibodies (MAbs) directed against epitopes in the V2 domain of human immunodeficiency virus type 1 gp120 often possess neutralizing activity, but these generally are highly type specific, neutralize only laboratory isolates, or have low potency. The most potent of these is C108g, directed against a type-specific epitope in HXB2 and BaL gp120s, which is glycan dependent and, in contrast to previous reports, dependent on intact disulfide bonds. This epitope was introduced into two primary Envs, derived from a neutralization-sensitive (SF162) and a neutralization-resistant (JR-FL) isolate, by substitution of two residues and, for SF162, addition of an N-linked glycosylation site. C108g effectively neutralized both variant Envs with considerably higher potency than standard MAbs against the V3 and CD4-binding domains and the broadly neutralizing MAbs 2G12 and 2F5. These amino acid substitutions also introduced the epitope recognized by a second V2-specific MAb, 10/76b, but this MAb possessed potent neutralizing activity only in the absence of the glycan required for C108g reactivity. In contrast to other gp120-specific neutralizing MAbs, C108g did not block binding of soluble Env proteins to either the CD4 or the CCR5 receptor, but studies with a fusion-arrested Env indicated that C108g neutralized at a step preceding the one blocked by the gp41-specific MAb, 2F5. These results indicate that the V1/V2 domain possesses targets that mediate potent neutralization of primary viral isolates via a novel mechanism and suggest that inclusion of carbohydrate determinants into these epitopes may help overcome the indirect masking effects that limit the neutralizing potency of antibodies commonly produced after infection.
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Affiliation(s)
- Abraham Pinter
- Laboratory of Retroviral Biology, Public Health Research Institute, 225 Warren Street, Newark, NJ 07103-3535, USA.
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24
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Becker Y. HIV-1 gp120 binding to dendritic cell receptors mobilize the virus to the lymph nodes, but the induced IL-4 synthesis by FcepsilonRI+ hematopoietic cells damages the adaptive immunity--a review, hypothesis, and implications. Virus Genes 2004; 29:147-65. [PMID: 15215692 DOI: 10.1023/b:viru.0000032797.43537.d3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
HIV-1 is equipped with the envelope gp160 glycoprotein for interaction with Langerhans cells (LCs) and dendritic cells (DCs), the members of the innate immune system, which confront the virus at the portal of virus entry in the human body. These cells are equipped with receptors by which they bind and endocytose the virus. The gp120 glycoprotein is used for binding to CD4 receptor and CCR5 co-receptor of T helper 2 (Th2) cells and the virions shed gp120 is able to induce FcepsilonRI+ hematopoietic cells to produce IL-4, which inactivate the host adaptive immune response. The properties of gp120s various functional domains are analyzed together with the regulatory viral proteins, which are involved in the damage to T and B cells during HIV-1 replication. The interaction of HIV-1 virions through their gp120 with LCs and DCs at the portal of virus entry will be discussed. A hypothesis will be presented that the understanding of the role of the different functional domains of gp120 in the life cycle of the virus and during AIDS will help in the design of approaches to prevent and abrogate HIV-1 infection and AIDS.
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Affiliation(s)
- Yechiel Becker
- Department of Molecular Virology, Faculty of Medicine, the Hebrew University of Jerusalem, P.O. Box 12272, 91120, Israel.
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25
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Brown SA, Stambas J, Zhan X, Slobod KS, Coleclough C, Zirkel A, Surman S, White SW, Doherty PC, Hurwitz JL. Clustering of Th cell epitopes on exposed regions of HIV envelope despite defects in antibody activity. THE JOURNAL OF IMMUNOLOGY 2004; 171:4140-8. [PMID: 14530336 DOI: 10.4049/jimmunol.171.8.4140] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A long-standing question in the field of immunology concerns the factors that contribute to Th cell epitope immunodominance. For a number of viral membrane proteins, Th cell epitopes are localized to exposed protein surfaces, often overlapping with Ab binding sites. It has therefore been proposed that Abs on B cell surfaces selectively bind and protect exposed protein fragments during Ag processing, and that this interaction helps to shape the Th cell repertoire. While attractive in concept, this hypothesis has not been thoroughly tested. To test this hypothesis, we have compared Th cell peptide immunodominance in normal C57BL/6 mice with that in C57BL/6( micro MT/ micro MT) mice (lacking normal B cell activity). Animals were first vaccinated with DNA constructs expressing one of three different HIV envelope proteins, after which the CD4(+) T cell response profiles were characterized toward overlapping peptides using an IFN-gamma ELISPOT assay. We found a striking similarity between the peptide response profiles in the two mouse strains. Profiles also matched those of previous experiments in which different envelope vaccination regimens were used. Our results clearly demonstrate that normal Ab activity is not required for the establishment or maintenance of Th peptide immunodominance in the HIV envelope response. To explain the clustering of Th cell epitopes, we propose that localization of peptide on exposed envelope surfaces facilitates proteolytic activity and preferential peptide shuttling through the Ag processing pathway.
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MESH Headings
- AIDS Vaccines/administration & dosage
- AIDS Vaccines/immunology
- Amino Acid Sequence
- Animals
- Antigen Presentation/genetics
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- CD4-Positive T-Lymphocytes/virology
- Enzyme-Linked Immunosorbent Assay
- Epitopes, T-Lymphocyte/administration & dosage
- Epitopes, T-Lymphocyte/immunology
- Epitopes, T-Lymphocyte/metabolism
- Female
- Gene Products, env/administration & dosage
- Gene Products, env/immunology
- Gene Products, env/metabolism
- HIV Antibodies/biosynthesis
- HIV Antibodies/genetics
- HIV Antibodies/metabolism
- HIV-1/immunology
- Humans
- Hybridomas
- Immunodominant Epitopes/administration & dosage
- Immunodominant Epitopes/immunology
- Immunodominant Epitopes/metabolism
- Lymphopenia/genetics
- Lymphopenia/immunology
- Mice
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Molecular Sequence Data
- T-Lymphocytes, Helper-Inducer/immunology
- T-Lymphocytes, Helper-Inducer/metabolism
- T-Lymphocytes, Helper-Inducer/virology
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Affiliation(s)
- Scott A Brown
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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26
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Labrijn AF, Poignard P, Raja A, Zwick MB, Delgado K, Franti M, Binley J, Vivona V, Grundner C, Huang CC, Venturi M, Petropoulos CJ, Wrin T, Dimitrov DS, Robinson J, Kwong PD, Wyatt RT, Sodroski J, Burton DR. Access of antibody molecules to the conserved coreceptor binding site on glycoprotein gp120 is sterically restricted on primary human immunodeficiency virus type 1. J Virol 2003; 77:10557-65. [PMID: 12970440 PMCID: PMC228502 DOI: 10.1128/jvi.77.19.10557-10565.2003] [Citation(s) in RCA: 308] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Anti-human immunodeficiency virus type 1 (HIV-1) antibodies whose binding to gp120 is enhanced by CD4 binding (CD4i antibodies) are generally considered nonneutralizing for primary HIV-1 isolates. However, a novel CD4i-specific Fab fragment, X5, has recently been found to neutralize a wide range of primary isolates. To investigate the precise nature of the extraordinary neutralizing ability of Fab X5, we evaluated the abilities of different forms (immunoglobulin G [IgG], Fab, and single-chain Fv) of X5 and other CD4i monoclonal antibodies to neutralize a range of primary HIV-1 isolates. Our results show that, for a number of isolates, the size of the neutralizing agent is inversely correlated with its ability to neutralize. Thus, the poor ability of CD4i-specific antibodies to neutralize primary isolates is due, at least in part, to steric factors that limit antibody access to the gp120 epitopes. Studies of temperature-regulated neutralization or fusion-arrested intermediates suggest that the steric effects are important in limiting the binding of IgG to the viral envelope glycoproteins after HIV-1 has engaged CD4 on the target cell membrane. The results identify hurdles in using CD4i epitopes as targets for antibody-mediated neutralization in vaccine design but also indicate that the CD4i regions could be efficiently targeted by small molecule entry inhibitors.
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Affiliation(s)
- Aran F Labrijn
- Department of Immunology, The Scripps Research Institute, La Jolla, California 92037, USA
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27
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Xiang SH, Kwong PD, Gupta R, Rizzuto CD, Casper DJ, Wyatt R, Wang L, Hendrickson WA, Doyle ML, Sodroski J. Mutagenic stabilization and/or disruption of a CD4-bound state reveals distinct conformations of the human immunodeficiency virus type 1 gp120 envelope glycoprotein. J Virol 2002; 76:9888-99. [PMID: 12208966 PMCID: PMC136507 DOI: 10.1128/jvi.76.19.9888-9899.2002] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) gp120 exterior envelope glycoprotein is conformationally flexible. Upon binding to the host cell receptor CD4, gp120 assumes a conformation that is recognized by the second receptor, CCR5 and/or CXCR4, and by the CD4-induced (CD4i) antibodies. Guided by the X-ray crystal structure of a gp120-CD4-CD4i antibody complex, we introduced changes into gp120 that were designed to stabilize or disrupt this conformation. One mutant, 375 S/W, in which the tryptophan indole group is predicted to occupy the Phe 43 cavity in the gp120 interior, apparently favors a gp120 conformation closer to that of the CD4-bound state. The 375 S/W mutant was recognized as well as or better than wild-type gp120 by CD4 and CD4i antibodies, and the large decrease in entropy observed when wild-type gp120 bound CD4 was reduced for the 375 S/W mutant. The recognition of the 375 S/W mutant by CD4BS antibodies, which are directed against the CD4-binding region of gp120, was markedly reduced compared with that of the wild-type gp120. Compared with the wild-type virus, viruses with the 375 S/W envelope glycoproteins were resistant to neutralization by IgG1b12, a CD4BS antibody, were slightly more sensitive to soluble CD4 neutralization and were neutralized more efficiently by the 2G12 antibody. Another mutant, 423 I/P, in which the gp120 bridging sheet was disrupted, did not bind CD4, CCR5, or CD4i antibodies, even though recognition by CD4BS antibodies was efficient. These results indicate that CD4BS antibodies recognize conformations of gp120 different from that recognized by CD4 and CD4i antibodies.
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Affiliation(s)
- Shi-Hua Xiang
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute and Harvard Medical School. Boston, Massachusetts 02115, USA
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28
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He Y, Honnen WJ, Krachmarov CP, Burkhart M, Kayman SC, Corvalan J, Pinter A. Efficient isolation of novel human monoclonal antibodies with neutralizing activity against HIV-1 from transgenic mice expressing human Ig loci. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:595-605. [PMID: 12077293 DOI: 10.4049/jimmunol.169.1.595] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Despite considerable interest in the isolation of mAbs with potent neutralization activity against primary HIV-1 isolates, both for identifying useful targets for vaccine development and for the development of therapeutically useful reagents against HIV-1 infection, a relatively limited number of such reagents have been isolated to date. Human mAbs (hu-mAbs) are preferable to rodent mAbs for treatment of humans, but isolation of hu-mAbs from HIV-infected subjects by standard methods of EBV transformation of B cells or phage display of Ig libraries is inefficient and limited by the inability to control or define the original immunogen. An alternative approach for the isolation of hu-mAbs has been provided by the development of transgenic mice that produce fully hu-mAbs. In this report, we show that immunizing the XenoMouse G2 strain with native recombinant gp120 derived from HIV(SF162) resulted in robust humoral Ab responses against gp120 and allowed the efficient isolation of hybridomas producing specific hu-mAbs directed against multiple regions and epitopes of gp120. hu-mAbs possessing strong neutralizing activity against the autologous HIV(SF162) strain were obtained. The epitopes recognized were located in three previously described neutralization domains, the V2-, V3- and CD4-binding domains, and in a novel neutralization domain, the highly variable C-terminal region of the V1 loop. This is the first report of neutralizing mAbs directed at targets in the V1 region. Furthermore, the V2 and V3 epitopes recognized by neutralizing hu-mAbs were distinct from those of previously described human and rodent mAbs and included an epitope requiring a full length V3 loop peptide for effective presentation. These results further our understanding of neutralization targets for primary, R5 HIV-1 viruses and demonstrate the utility of the XenoMouse system for identifying new and interesting epitopes on HIV-1.
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MESH Headings
- Amino Acid Sequence
- Animals
- Anti-HIV Agents/chemistry
- Anti-HIV Agents/isolation & purification
- Anti-HIV Agents/pharmacology
- Antibodies, Heterophile/chemistry
- Antibodies, Heterophile/genetics
- Antibodies, Heterophile/isolation & purification
- Antibodies, Heterophile/pharmacology
- Antibodies, Monoclonal/biosynthesis
- Antibodies, Monoclonal/genetics
- Antibodies, Monoclonal/isolation & purification
- Antibodies, Monoclonal/pharmacology
- Antibody Specificity/genetics
- Binding, Competitive/genetics
- Binding, Competitive/immunology
- Conserved Sequence/immunology
- Epitope Mapping
- Epitopes/chemistry
- Epitopes/immunology
- Gene Expression Regulation/immunology
- Genes, Immunoglobulin
- Genetic Markers/immunology
- HIV Antibodies/biosynthesis
- HIV Antibodies/genetics
- HIV Antibodies/isolation & purification
- HIV Antibodies/pharmacology
- HIV Envelope Protein gp120/immunology
- HIV-1/immunology
- Humans
- Hybridomas
- Immunoglobulin Variable Region/chemistry
- Immunoglobulin Variable Region/genetics
- Mice
- Mice, Transgenic
- Molecular Sequence Data
- Neutralization Tests/methods
- Protein Structure, Tertiary/genetics
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Affiliation(s)
- Yuxian He
- Laboratory of Retroviral Biology, Public Health Research Institute, Newark, NJ 07103-3535, USA
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29
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Moore JP, Parren PW, Burton DR. Genetic subtypes, humoral immunity, and human immunodeficiency virus type 1 vaccine development. J Virol 2001; 75:5721-9. [PMID: 11390574 PMCID: PMC114288 DOI: 10.1128/jvi.75.13.5721-5729.2001] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- J P Moore
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, 1300 York Ave., New York, NY 10021, USA.
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30
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Yang X, Wyatt R, Sodroski J. Improved elicitation of neutralizing antibodies against primary human immunodeficiency viruses by soluble stabilized envelope glycoprotein trimers. J Virol 2001; 75:1165-71. [PMID: 11152489 PMCID: PMC114022 DOI: 10.1128/jvi.75.3.1165-1171.2001] [Citation(s) in RCA: 174] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus (HIV-1) envelope glycoprotein subunits, such as the gp120 exterior glycoprotein, typically elicit antibodies that neutralize T-cell-line-adapted (TCLA), but not primary, clinical isolates of HIV-1. Here we compare the immunogenicity of gp120 and soluble stabilized trimers, which were designed to resemble the functional envelope glycoprotein oligomers of primary and TCLA HIV-1 strains. For both primary and TCLA virus proteins, soluble stabilized trimers generated neutralizing antibody responses more efficiently than gp120 did. Trimers derived from a primary isolate elicited antibodies that neutralized primary and TCLA HIV-1 strains. By contrast, trimers derived from a TCLA isolate generated antibodies that neutralized only the homologous TCLA virus. Thus, soluble stabilized envelope glycoprotein trimers derived from primary HIV-1 isolates represent defined immunogens capable of eliciting neutralizing antibodies that are active against clinically relevant HIV-1 strains.
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Affiliation(s)
- X Yang
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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31
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Ozyörük F, Cheevers WP, Hullinger GA, McGuire TC, Hutton M, Knowles DP. Monoclonal antibodies to conformational epitopes of the surface glycoprotein of caprine arthritis-encephalitis virus: potential application to competitive-inhibition enzyme-linked immunosorbent assay for detecting antibodies in goat sera. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2001; 8:44-51. [PMID: 11139194 PMCID: PMC96009 DOI: 10.1128/cdli.8.1.44-51.2001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Four immunoglobulin G1 monoclonal antibodies (MAbs) to the gp135 surface envelope glycoprotein (SU) of the 79-63 isolate of caprine arthritis-encephalitis virus (CAEV), referred to as CAEV-63, were characterized and evaluated for their ability to compete with antibody from CAEV-infected goats. Three murine MAbs (MAbs GPB16A, 29A, and 74A) and one caprine MAb (MAb F7-299) were examined. All MAbs reacted in nitrocellulose dot blots with native CAEV-63 SU purified by MAb F7-299 affinity chromatography, whereas none reacted with denatured and reduced SU. All MAbs reacted in Western blots with purified CAEV-63 SU or the SU component of whole-virus lysate following denaturation in the absence of reducing agent, indicating that intramolecular disulfide bonding was essential for epitope integrity. Peptide-N-glycosidase F digestion of SU abolished the reactivities of MAbs 74A and F7-299, whereas treatment of SU with N-acetylneuraminate glycohydrolase (sialidase A) under nonreducing conditions enhanced the reactivities of all MAbs as well as polyclonal goat sera. MAbs 29A and F7-299 were cross-reactive with the SU of an independent strain of CAEV (CAEV-Co). By enzyme-linked immunosorbent assay (ELISA), the reactivities of horseradish peroxidase (HRP)-conjugated MAbs 16A and 29A with homologous CAEV-63 SU were <10% of that of HRP-conjugated MAb 74A. The reactivity of HRP-conjugated MAb 74A was blocked by sera from goats immunized with CAEV-63 SU or infected with CAEV-63. The reactivity of MAb 74A was also blocked by sera from goats infected with a CAEV-Co molecular clone, although MAb 74A did not react with CAEV-Co SU in Western blots. Thus, goats infected with either CAEV-63 or CAEV-Co make antibodies that inhibit binding of MAb 74A to CAEV-63 SU. A competitive-inhibition ELISA based on displacement of MAb 74A reactivity has potential applicability for the serologic diagnosis of CAEV infection.
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Affiliation(s)
- F Ozyörük
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99164-7040, USA
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32
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Ye Y, Si ZH, Moore JP, Sodroski J. Association of structural changes in the V2 and V3 loops of the gp120 envelope glycoprotein with acquisition of neutralization resistance in a simian-human immunodeficiency virus passaged in vivo. J Virol 2000; 74:11955-62. [PMID: 11090196 PMCID: PMC112479 DOI: 10.1128/jvi.74.24.11955-11962.2000] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The in vivo passage of a neutralization-sensitive, laboratory-adapted simian-human immunodeficiency virus (SHIV-HXBc2) generated a pathogenic, neutralization-resistant virus, SHIV-HXBc2P 3.2. SHIV-HXBc2P 3.2 differs from SHIV-HXBc2 only in 13 amino acid residues of the viral envelope glycoproteins. Here we used antibody competition analysis to examine the structural changes that occurred in the SHIV-HXBc2P 3.2 gp120 exterior envelope glycoprotein. The relationships among the antibody epitopes on the conserved gp120 core of SHIV-HXBc2 and SHIV-HXBc2P 3.2 were similar. The third variable (V3) loop was more closely associated with the fourth conserved (C4) region and CD4-induced epitopes on the gp120 core in the HXBc2P 3.2 gp120 glycoprotein compared with the HXBc2 gp120 glycoprotein. Rearrangements of the second variable (V2) loop with respect to the CD4 binding site and associated epitopes were evident in comparisons of the two gp120 glycoproteins. Thus, the in vivo evolution of a neutralization-resistant virus involves conformational adjustments of the V2 and V3 variable loops with respect to the conserved receptor-binding regions of the gp120 core.
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Affiliation(s)
- Y Ye
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10016, USA
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33
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Phan KO, Callahan ME, Vanichseni S, Hu DJ, Raktham S, Young N, Choopanya K, Mastro TD, Subbarao S. A comparison of full-length glycoprotein 120 from incident HIV type 1 subtype E and B infections in Bangkok injecting drug users with prototype E and B strains that are components of a candidate vaccine. AIDS Res Hum Retroviruses 2000; 16:1445-50. [PMID: 11018864 DOI: 10.1089/08892220050140991] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
Abstract
Complete gp120 sequence information was obtained from eight persons with incident HIV-1 infections (four subtype E and four subtype B) who were part of a prospective injecting drug user (IDU) cohort in Bangkok, Thailand, during 1996-1998. The incident subtype E strains were similar to the prototype subtype E strain CM244 isolated in 1992 in northern Thailand. The incident subtype B strains displayed divergence, in both overall genetic distance and other significant gp120 characteristics, from the prototype North American subtype B strain HIV-MN. Recombinant gp120s derived from CM244 and HIV-MN strains are components of a vaccine that is undergoing phase III efficacy testing, begun in March 1999, among Bangkok area IDUs. The information presented here will be important in the evaluation of any breakthrough HIV-1 infections occurring among vaccinees during the vaccine trial and in ongoing vaccine development efforts in Thailand.
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Affiliation(s)
- K O Phan
- Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA
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34
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Edinger AL, Ahuja M, Sung T, Baxter KC, Haggarty B, Doms RW, Hoxie JA. Characterization and epitope mapping of neutralizing monoclonal antibodies produced by immunization with oligomeric simian immunodeficiency virus envelope protein. J Virol 2000; 74:7922-35. [PMID: 10933700 PMCID: PMC112323 DOI: 10.1128/jvi.74.17.7922-7935.2000] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In an attempt to generate broadly cross-reactive, neutralizing monoclonal antibodies (MAbs) to simian immunodeficiency virus (SIV), we compared two immunization protocols using different preparations of oligomeric SIV envelope (Env) glycoproteins. In the first protocol, mice were immunized with soluble gp140 (sgp140) from CP-MAC, a laboratory-adapted variant of SIVmacBK28. Hybridomas were screened by enzyme-linked immunosorbent assay, and a panel of 65 MAbs that recognized epitopes throughout the Env protein was generated. In general, these MAbs detected Env by Western blotting, were at least weakly positive in fluorescence-activated cell sorting (FACS) analysis of Env-expressing cells, and preferentially recognized monomeric Env protein. A subset of these antibodies directed toward the V1/V2 loop, the V3 loop, or nonlinear epitopes were capable of neutralizing CP-MAC, a closely related isolate (SIVmac1A11), and/or two more divergent strains (SIVsmDeltaB670 CL3 and SIVsm543-3E). In the second protocol, mice were immunized with unfixed CP-MAC-infected cells and MAbs were screened for the ability to inhibit cell-cell fusion. In contrast to MAbs generated against sgp140, the seven MAbs produced using this protocol did not react with Env by Western blotting and were strongly positive by FACS analysis, and several reacted preferentially with oligomeric Env. All seven MAbs potently neutralized SIVmac1A11, and several neutralized SIVsmDeltaB670 CL3 and/or SIVsm543-3E. MAbs that inhibited gp120 binding to CD4, CCR5, or both were identified in both groups. MAbs to the V3 loop and one MAb reactive with the V1/V2 loop interfered with CCR5 binding, indicating that these regions of Env play similar roles for SIV and human immunodeficiency virus. Remarkably, several of the MAbs generated against infected cells blocked CCR5 binding in a V3-independent manner, suggesting that they may recognize a region analogous to the conserved coreceptor binding site in gp120. Finally, all neutralizing MAbs blocked infection through the alternate coreceptor STRL33 much more efficiently than infection through CCR5, a finding that has important implications for SIV neutralization assays using CCR5-negative human T-cell lines.
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Affiliation(s)
- A L Edinger
- Department of Pathology and Laboratory Medicine, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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35
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Ly A, Stamatatos L. V2 loop glycosylation of the human immunodeficiency virus type 1 SF162 envelope facilitates interaction of this protein with CD4 and CCR5 receptors and protects the virus from neutralization by anti-V3 loop and anti-CD4 binding site antibodies. J Virol 2000; 74:6769-76. [PMID: 10888615 PMCID: PMC112193 DOI: 10.1128/jvi.74.15.6769-6776.2000] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We examined the role of asparagine-linked glycosylation of the V2 loop of the human immunodeficiency virus (HIV) SF162 envelope on viral replication potential and neutralization susceptibility. We report that the asparagines located at the amino- and carboxy-terminal sites (at positions 154 and 195, respectively), as well as within the V2 loop of the SF162 envelope (at position 186), are glycosylated during in vitro replication of this virus in human peripheral blood mononuclear cells. Our studies indicate that glycosylation of the V2 loop, in particular at its base, facilitates the interaction of the HIV envelope with the CD4 and CCR5 receptor molecules present on the surface of target cells and affects viral replication kinetics in a cell type-dependent manner. In cells expressing high numbers of receptor molecules on their surfaces, the SF162-derived V2 loop-deglycosylated mutant viruses replicate as efficiently as the parental SF162 virus, while in cells expressing small numbers of receptor molecules, the mutant viruses replicate with markedly reduced efficiency. In addition to expanding the viral tropism, V2 loop glycosylation at the three sites examined prevents neutralization by anti-CD4 binding site antibodies. In contrast, glycosylation at the amino- and carboxy-terminal sites of the V2 loop but not within the loop itself offers protection against anti-V3 loop antibodies. Thus, the epitopes masked by the sugar molecules present on the three glycosylation sites examined are not identical but overlap.
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Affiliation(s)
- A Ly
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10021-6399, USA.
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36
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Valas S, Benoit C, Baudry C, Perrin G, Mamoun RZ. Variability and immunogenicity of caprine arthritis-encephalitis virus surface glycoprotein. J Virol 2000; 74:6178-85. [PMID: 10846103 PMCID: PMC112118 DOI: 10.1128/jvi.74.13.6178-6185.2000] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The complete surface glycoprotein (SU) nucleotide sequences of three French isolates of caprine arthritis-encephalitis virus (CAEV) were determined and compared with those of previously described isolates: three American isolates and one French isolate. Phylogenetic analyses revealed the existence of four distinct and roughly equidistant evolutionary CAEV subtypes. Four conserved and five variable domains were identified in the SU. The fine specificities of antibodies produced against these domains during natural infection were examined using a pepscan analysis. Nine immunogenic segments were delineated throughout the conserved and variable domains of SU, two of them corresponding to conserved immunodominant epitopes. Antigenic determinants which may be involved in the immunopathogenic process induced by CAEV were identified. These results also provide sensitive and specific antigen peptides for the serological detection and differentiation of CAEV and visna/maedi virus infections.
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Affiliation(s)
- S Valas
- AFSSA-Niort, Laboratoire de Recherches Caprines, F-79012 Niort Cedex, France.
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37
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Rizzuto C, Sodroski J. Fine definition of a conserved CCR5-binding region on the human immunodeficiency virus type 1 glycoprotein 120. AIDS Res Hum Retroviruses 2000; 16:741-9. [PMID: 10826481 DOI: 10.1089/088922200308747] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A previous study implicated a conserved surface of the human immunodeficiency virus (HIV-1) gp120 exterior envelope glycoprotein in binding the CCR5 viral coreceptor (Rizzuto C, Wyatt R, Hernández-Ramos N, Sun Y, Kwong PD, Hendrickson WA, and Sodroski J: Science 1998;280:1949-1953). Additional mutagenesis indicates that important residues in this region for CCR5 binding are Ile-420, Lys-421, Gln-422, Pro-438, and Gly-441. These highly conserved residues are located on two strands that connect the gp120 bridging sheet and outer domain, suggesting a mechanism whereby interdomain conformational shifts induced by CD4 binding could facilitate CCR5 binding.
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Affiliation(s)
- C Rizzuto
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA
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38
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Center RJ, Earl PL, Lebowitz J, Schuck P, Moss B. The human immunodeficiency virus type 1 gp120 V2 domain mediates gp41-independent intersubunit contacts. J Virol 2000; 74:4448-55. [PMID: 10775580 PMCID: PMC111965 DOI: 10.1128/jvi.74.10.4448-4455.2000] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The envelope protein of human immunodeficiency virus type 1 HIV-1 undergoes proteolytic cleavage in the Golgi complex to produce subunits designated gp120 and gp41, which remain noncovalently associated. While gp41 has a well-characterized oligomeric structure, the maintenance of gp41-independent gp120 intersubunit contacts remains a contentious issue. Using recombinant vaccinia virus to achieve high-level expression of gp120 in mammalian cells combined with gel filtration analysis, we were able to isolate a discrete oligomeric form of gp120. Oligomerization of gp120 occurred intracellularly between 30 and 120 min after synthesis. Analysis by sedimentation equilibrium unequivocally identified the oligomeric species as a dimer. In order to identify the domains involved in the intersubunit contact, we expressed a series of gp120 proteins lacking various domains and assessed the effects of mutation on oligomeric structure. Deletion of the V1 or V3 loops had little effect on the relative amounts of monomer and dimer in comparison to wild-type gp120. In contrast, deletion of either all or part of the V2 loop drastically reduced dimer formation, indicating that this domain is required for intersubunit contact formation. Consistent with this, the V2 loop of the dimer was less accessible than that of the monomer to a specific monoclonal antibody. Previous studies have shown that while the V2 loop is not an absolute requirement for viral entry, the absence of this domain reduces viral resistance to neutralization by monoclonal antibodies or sera. We propose that the quaternary structure of gp120 may contribute to resistance to neutralization by limiting the exposure of conserved epitopes.
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Affiliation(s)
- R J Center
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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Salzwedel K, Smith ED, Dey B, Berger EA. Sequential CD4-coreceptor interactions in human immunodeficiency virus type 1 Env function: soluble CD4 activates Env for coreceptor-dependent fusion and reveals blocking activities of antibodies against cryptic conserved epitopes on gp120. J Virol 2000; 74:326-33. [PMID: 10590121 PMCID: PMC111543 DOI: 10.1128/jvi.74.1.326-333.2000] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/1999] [Accepted: 09/27/1999] [Indexed: 11/20/2022] Open
Abstract
We devised an experimental system to examine sequential events by which the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) interacts with CD4 and coreceptor to induce membrane fusion. Recombinant soluble CD4 (sCD4) activated fusion between effector cells expressing Env and target cells expressing coreceptor (CCR5 or CXCR4) but lacking CD4. sCD4-activated fusion was dose dependent, occurred comparably with two- and four-domain proteins, and demonstrated Env-coreceptor specificities parallel to those reported in conventional fusion and infectivity systems. Fusion activation occurred upon sCD4 preincubation and washing of the Env-expressing effector cells but not the coreceptor-bearing target cells, thereby demonstrating that sCD4 exerts its effects by acting on Env. These findings provide direct functional evidence for a sequential two-step model of Env-receptor interactions, whereby gp120 binds first to CD4 and becomes activated for subsequent functional interaction with coreceptor, leading to membrane fusion. We used the sCD4-activated system to explore neutralization by the anti-gp120 human monoclonal antibodies 17b and 48d. These antibodies reportedly bind conserved CD4-induced epitopes involved in coreceptor interactions but neutralize HIV-1 infection only weakly. We found that 17b and 48d had minimal effects in the standard cell fusion system using target cells expressing both CD4 and coreceptor but potently blocked sCD4-activated fusion with target cells expressing coreceptor alone. Both antibodies strongly inhibited sCD4-activated fusion by Envs from genetically diverse HIV-1 isolates. Thus, the sCD4-activated system reveals conserved Env-blocking epitopes that are masked in native Env and hence not readily detected by conventional systems.
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Affiliation(s)
- K Salzwedel
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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Etemad-Moghadam B, Sun Y, Nicholson EK, Karlsson GB, Schenten D, Sodroski J. Determinants of neutralization resistance in the envelope glycoproteins of a simian-human immunodeficiency virus passaged in vivo. J Virol 1999; 73:8873-9. [PMID: 10482646 PMCID: PMC112913 DOI: 10.1128/jvi.73.10.8873-8879.1999] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In vivo passage of a simian-human immunodeficiency virus (SHIV-89.6) generated a virus, SHIV-89.6P, that exhibited increased resistance to some neutralizing antibodies (G. B. Karlsson et al., J. Exp. Med. 188:1159-1171, 1998). Here we examine the range of human immunodeficiency virus type 1 (HIV-1) neutralizing antibodies to which the passaged virus became resistant and identify envelope glycoprotein determinants of antibody resistance. Compared with the envelope glycoproteins derived from the parental SHIV-89.6, the envelope glycoproteins of the passaged virus were resistant to antibodies directed against the gp120 V3 variable loop and the CD4 binding site. By contrast, both viral envelope glycoproteins were equally sensitive to neutralization by two antibodies, 2G12 and 2F5, that recognize poorly immunogenic structures on gp120 and gp41, respectively. Changes in the V2 and V3 variable loops of gp120 were necessary and sufficient for full resistance to the IgG1b12 antibody, which is directed against the CD4 binding site. Changes in the V3 loop specified complete resistance to a V3 loop-directed antibody, while changes in the V1/V2 loops conferred partial resistance to this antibody. The epitopes of the neutralizing antibodies were not disrupted by the resistance-associated changes. These results indicate that in vivo selection occurs for HIV-1 envelope glycoproteins with variable loop conformations that restrict the access of antibodies to immunogenic neutralization epitopes.
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Affiliation(s)
- B Etemad-Moghadam
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
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41
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Quinnan GV, Zhang PF, Fu DW, Dong M, Alter HJ. Expression and characterization of HIV type 1 envelope protein associated with a broadly reactive neutralizing antibody response. AIDS Res Hum Retroviruses 1999; 15:561-70. [PMID: 10221533 DOI: 10.1089/088922299311088] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We have studied envelope protein from a donor with nonprogressive HIV-1 infection whose serum contains broadly cross-reactive, primary virus NA. DNA was extracted from lymphocytes, which had been collected approximately 6 and 12 months prior to the time of collection of the cross-reactive serum, and env genes were synthesized, cloned, expressed on pseudoviruses, and phenotyped in NA assays. Two clones from each time point had identical V3 region nucleotide sequences, utilized CCR5 but not CXCR4 for cell entry, and had similar reactivities with reference sera. Analysis of the full nucleotide sequence of one clone (R2) demonstrated it to be subtype B and have normal predicted glycosylation. R2 pseudovirus was compared with others expressing env genes of various clades for neutralization by sera from U.S. donors (presumed or known subtype B infections), and from individuals infected with subtypes A, C, D, E, and F viruses. Neutralization by the U.S. sera of R2 and other clade B pseudoviruses was low to moderate, although R2 was uniquely neutralized by all. R2 was neutralized by 3/3, 3/3, 2/5, 5/8, and 3/4 clade A, C, D, E, and F sera, respectively. R2 and a clade E pseudovirus were neutralized by largely complementary groups of sera, potentially defining two antigenic subgroups of HIV-1. The results suggest that the epitope(s) that induced the cross-clade reactive NA in donor 2 may be expressed on the R2 envelope.
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Affiliation(s)
- G V Quinnan
- Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA
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42
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Kayman SC, Park H, Saxon M, Pinter A. The hypervariable domain of the murine leukemia virus surface protein tolerates large insertions and deletions, enabling development of a retroviral particle display system. J Virol 1999; 73:1802-8. [PMID: 9971757 PMCID: PMC104419 DOI: 10.1128/jvi.73.3.1802-1808.1999] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/1998] [Accepted: 12/04/1998] [Indexed: 11/20/2022] Open
Abstract
The surface proteins (SU) of murine type-C retroviruses have a central hypervariable domain devoid of cysteine and rich in proline. This 41-amino-acid region of Friend ecotropic murine leukemia virus SU was shown to be highly tolerant of insertions and deletions. Viruses in which either the N-terminal 30 amino acids or the C-terminal 22 amino acids of this region were replaced by the 7-amino-acid sequence ASAVAGA were fully infectious. Insertions of this 7-amino-acid sequence at the N terminus, center, and the C terminus of the hypervariable domain had little effect on envelope protein (Env) function, while this insertion at a position 10 amino acids following the N terminus partially destabilized the association between the SU and transmembrane subunits of Env. Large, complex domains (either a 252-amino-acid single-chain antibody binding domain [scFv] or a 96-amino-acid V1/V2 domain of HIV-1 SU containing eight N-linked glycosylation sites and two disulfides) did not interfere with Env function when inserted in the center or C-terminal portions of the hypervariable domain. The scFv domain inserted into the C-terminal region of the hypervariable domain was shown to mediate binding of antigen to viral particles, demonstrating that it folded into the active conformation and was displayed on the surface of the virion. Both positive and negative enrichment of virions expressing the V1/V2 sequence were achieved by using a monoclonal antibody specific for a conformational epitope presented by the inserted sequence. These results indicated that the hypervariable domain of Friend ecotropic SU does not contain any specific sequence or structure that is essential for Env function and demonstrated that insertions into this domain can be used to extend particle display methodologies to complex protein domains that require expression in eukaryotic cells for glycosylation and proper folding.
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Affiliation(s)
- S C Kayman
- Laboratory of Retroviral Biology, Public Health Research Institute, New York, New York 10016, USA.
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43
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Beddows S, Lister S, Cheingsong R, Bruck C, Weber J. Comparison of the antibody repertoire generated in healthy volunteers following immunization with a monomeric recombinant gp120 construct derived from a CCR5/CXCR4-using human immunodeficiency virus type 1 isolate with sera from naturally infected individuals. J Virol 1999; 73:1740-5. [PMID: 9882391 PMCID: PMC104010 DOI: 10.1128/jvi.73.2.1740-1745.1999] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have characterized sera from healthy volunteers immunized with a monomeric recombinant gp120 (rgp120) derived from a CCR5/CXCR4 (R5X4)-using subtype B isolate of human immunodeficiency virus type (HIV-1), HIV-1W61D, in comparison to sera from long-term HIV-1-infected individuals, using homologous reagents. Sera from vaccinees and HIV-1 positive subjects had similar binding titers to native monomeric rgp120W61D and showed a similar titer of antibodies inhibiting the binding of soluble CD4 (sCD4) to rgp120W61D. However, extensive peptide binding studies showed that the overall pattern of recognition of vaccinee and HIV-1-positive sera is different, with vaccinee sera displaying a wider and more potent recognition of linear V1/V2 and V3 domain epitopes. Neutralization of homologous HIV-1W61D or heterologous HIV-1M2424/4 peripheral blood mononuclear cell (PBMC)-derived virus lines by vaccinee sera could be achieved, but only after adaptation of the viruses to T-cell lines and was quickly lost on readaptation to growth in PBMC. Sera from HIV-positive individuals were able to neutralize both PBMC-grown and T-cell line-adapted viruses. Interestingly, rgp120W61D was recognized by monoclonal antibodies previously shown to neutralize primary HIV-1 isolates. The use of very potent adjuvants and R5X4 rgp120 led to an antibody response equivalent in binding activity and inhibition of binding of sCD4 to gp120 to that of HIV-positive individuals but did not lead to the induction of antibodies capable of neutralizing PBMC-grown virus.
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Affiliation(s)
- S Beddows
- Department of GU Medicine and Communicable Diseases, Imperial College School of Medicine at St. Mary's, London W2 1PG, United Kingdom
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44
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Petry H, Dittmer U, Jones D, Farrar G, Wachter H, Fuchs D, Nisslein T, Jurkiewicz E, Hunsmann G, Stahl-Hennig C, Lüke W. Prechallenge high neutralizing antibodies and long-lasting immune reactivity to gp41 correlate with protection of rhesus monkeys against productive simian immunodeficiency virus infection or disease development. JOURNAL OF ACQUIRED IMMUNE DEFICIENCY SYNDROMES AND HUMAN RETROVIROLOGY : OFFICIAL PUBLICATION OF THE INTERNATIONAL RETROVIROLOGY ASSOCIATION 1998; 19:441-50. [PMID: 9859957 DOI: 10.1097/00042560-199812150-00002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
To investigate the protective efficacy of various gp130 vaccine preparations, rhesus monkeys were immunized with gp130 oligomers (O-gp130) or two different gp130-monomer preparations (M1-gp130; M2-gp130) and challenged with 50 MID50 of simian immunodeficiency virus (SIV)mac32H. Following challenge the control animals and all animals of the M1- and M2-gp130 group and 1 animal of the O-gp130 group were productively infected, whereas 3 animals of the O-gp130 group resisted the productive virus replication. The protection was correlated with high neutralizing antibodies and a long-lasting immune response to the transmembrane protein gp41. Whereas none of the O-gp130 animals had developed disease symptoms, 3 M1-gp130 animals, 1 M2-gp130 animal, and 2 control animals died as a result of AIDS within 18 months after challenge. Therefore, immunization with virion-derived gp130 oligomers of SIVmac32H can confer protection against the productive infection with SIVmac32H and suppress the development of the AIDS-like disease.
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Affiliation(s)
- H Petry
- Department of Virology and Immunology, German Primate Center, Göttingen
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45
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46
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Etemad-Moghadam B, Karlsson GB, Halloran M, Sun Y, Schenten D, Fernandes M, Letvin NL, Sodroski J. Characterization of simian-human immunodeficiency virus envelope glycoprotein epitopes recognized by neutralizing antibodies from infected monkeys. J Virol 1998; 72:8437-45. [PMID: 9733899 PMCID: PMC110239 DOI: 10.1128/jvi.72.10.8437-8445.1998] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We characterized human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein epitopes recognized by neutralizing antibodies from monkeys recently infected by molecularly cloned simian-human immunodeficiency virus (SHIV) variants. The early neutralizing antibody response in each infected animal was directed mainly against a single epitope. This primary neutralizing epitope, however, differed among individual monkeys infected by identical viruses. Two such neutralization epitopes were determined by sequences in the V2 and V3 loops of the gp120 envelope glycoprotein, while a third neutralization epitope, apparently discontinuous, was determined by both V2 and V3 sequences. These results indicate that the early neutralizing antibody response in SHIV-infected monkeys is monospecific and directed against epitopes composed of the gp120 V2 and V3 variable loops.
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Affiliation(s)
- B Etemad-Moghadam
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
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47
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Stamatatos L, Cheng-Mayer C. An envelope modification that renders a primary, neutralization-resistant clade B human immunodeficiency virus type 1 isolate highly susceptible to neutralization by sera from other clades. J Virol 1998; 72:7840-5. [PMID: 9733820 PMCID: PMC110102 DOI: 10.1128/jvi.72.10.7840-7845.1998] [Citation(s) in RCA: 144] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SF162 is a primary (PR), non-syncytium-inducing, macrophagetropic human immunodeficiency virus type 1 (HIV-1) clade B isolate which is resistant to antibody-mediated neutralization. Deletion of the first or second hypervariable envelope gp120 region (V1 or V2 loop, respectively) of this virus does not abrogate its ability to replicate in peripheral blood mononuclear cells and primary macrophages, nor does it alter its coreceptor usage profile. The mutant virus with the V1 loop deletion, SF162DeltaV1, remains as resistant to antibody-mediated neutralization as the wild-type virus SF162. In contrast, the mutant virus with the V2 loop deletion, SF162DeltaV2, exhibits enhanced susceptibility to neutralization by certain monoclonal antibodies whose epitopes are located within the CD4-binding site and conserved regions of gp120. More importantly, SF162DeltaV2 is now up to 170-fold more susceptible to neutralization than SF162 by sera collected from patients infected with clade B HIV-1 isolates. In addition, it becomes susceptible to neutralization by sera collected from patients infected with clade A, C, D, E, and F HIV-1 isolates. These findings suggest that the V2, but not the V1, loop of SF162 shields an as yet unidentified region of the HIV envelope rich in neutralization epitopes and that the overall structure of this region appears to be conserved among clade B, C, D, E, and F HIV-1 PR isolates.
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Affiliation(s)
- L Stamatatos
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10021-6399, USA.
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48
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Stamatatos L, Wiskerchen M, Cheng-Mayer C. Effect of major deletions in the V1 and V2 loops of a macrophage-tropic HIV type 1 isolate on viral envelope structure, cell entry, and replication. AIDS Res Hum Retroviruses 1998; 14:1129-39. [PMID: 9737584 DOI: 10.1089/aid.1998.14.1129] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Two HIV-1 envelope mutant proteins were generated by introducing deletions in the first and second hypervariable gp120 regions (V1 and V2 loops, respectively) of a macrophage-tropic primary HIV-1 isolate, SF162, to study the effect of the deleted sequences on envelope structure, viral entry, and replication potentials. The first mutant lacked 17 amino acids of the V1 loop and the latter 30 amino acids of the V2 loop. A comparison of the immunochemical structure of the wild-type and mutant monomeric and virion-associated gp120 molecules revealed that the V1 and V2 loop deletions differentially altered the structure of the V3 loop, the CD4-binding site, and epitopes within conserved regions of gp120. Regardless of differences in structure, both mutated envelope proteins supported viral replication into peripheral blood mononuclear cells to levels comparable to those of the wild-type SF162 virus. However, they decreased the viral replication potential in macrophages, even though they did not alter the coreceptor usage of the viruses. These studies support and extend previous observations that a complex structural interaction between the V1, V2, and V3 loops and elements of the CD4-binding site of gp120 controls entry of virus into cells. The present studies, however, suggest that the effect of the V1 and V2 loops in viral entry is cell dependent.
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Affiliation(s)
- L Stamatatos
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10021, USA
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49
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Park EJ, Vujcic LK, Anand R, Theodore TS, Quinnan GV. Mutations in both gp120 and gp41 are responsible for the broad neutralization resistance of variant human immunodeficiency virus type 1 MN to antibodies directed at V3 and non-V3 epitopes. J Virol 1998; 72:7099-107. [PMID: 9696803 PMCID: PMC109931 DOI: 10.1128/jvi.72.9.7099-7107.1998] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/1998] [Accepted: 06/01/1998] [Indexed: 11/20/2022] Open
Abstract
The escape of human immunodeficiency virus type 1 from effects of neutralizing antibodies was studied by using neutralization-resistant (NR) variants generated by growing the neutralization-sensitive (NS) wild-type MN virus in the presence of human serum with neutralizing antibodies, more than 99% of which were directed at the V3 region of gp120. The variants obtained had broad neutralization resistance to human sera, without limitation with respect to the V3 specificity of the sera. The molecular basis for the resistance was evaluated with molecularly cloned viruses, as well as with pseudoviruses expressing envelope glycoproteins of the NS and NR phenotypes. Nucleotide sequence analyses comparing NS and NR clones revealed a number of polymorphisms, including six in the V1/V2 region, two in C4/V5 of gp120, three in the leucine zipper (LZ) domain of gp41, and two in the second external putative alpha-helix region of gp41. A series of chimeras from NS and NR env genes was constructed, and each was presented on pseudoviruses to locate the domain(s) which conferred the phenotypic changes. The neutralization phenotypes of the chimeric clones were found to be dependent on mutations in both the C4/V5 region of gp120 and the LZ region of gp41. Additionally, interaction between mutations in gp120 and gp41 was demonstrated in that a chimeric env gene consisting of a gp120 coding sequence from an NS clone and a gp41 sequence from an NR clone yielded a pseudovirus with minimal infectivity. The possible significance of predicted amino acid changes in these domains is discussed. The results indicate that polyvalent antibodies predominantly directed against V3 can induce NR through selection for mutations that alter interactions of other domains in the envelope complex.
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Affiliation(s)
- E J Park
- Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA
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50
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Quinnan GV, Zhang PF, Fu DW, Dong M, Margolick JB. Evolution of neutralizing antibody response against HIV type 1 virions and pseudovirions in multicenter AIDS cohort study participants. AIDS Res Hum Retroviruses 1998; 14:939-49. [PMID: 9686640 DOI: 10.1089/aid.1998.14.939] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Changes in neutralizing antibody (NA) titers in stored sera collected over 5 years from 10 participants in the Multicenter AIDS Cohort Study (MACS) were evaluated. The participants were HIV-1 infected on enrollment in the MACS, and remained AIDS free during the 5-year study interval. Seven viruses derived from molecular clones were used in NA assays; five of the viruses were T tropic (NL4-3, ALA1, NY5, SF2, and Z2Z6) and two were M tropic [AD8 and NL(SF162)]. In addition, pseudoviruses (PVs) were constructed that expressed envelope genes from NL4-3, ALA1, AD8, and SF162 and from primary viruses from two MACS participants (PV-9 and PV-10). There was significant correlation between NA titers obtained in four of five virus/PV comparisons, while the SF162 PV was more sensitive to NA than the corresponding virus. Comparable changes in NA titers were detected using viruses and PVs. Fourfold or greater increases in NA titers were noted in each of the participants, involving recognition of one to five of the nine strains tested. In some patients these NA titer changes appeared as discrete episodes of immune responses, while in others there may have been either multiple episodes or continuous evolution of the NA responses. The data indicate that changes in NA specificity occur during HIV-1 infection, which may result from the occurrence of neutralization escape mutation. The use of PVs for the study of phenotypic characteristics of envelope glycoproteins should facilitate the study of neutralization escape mutation in HIV-1 infection.
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Affiliation(s)
- G V Quinnan
- Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA
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