1
|
Mkhize NN, Yssel AEJ, Kaldine H, van Dorsten RT, Woodward Davis AS, Beaume N, Matten D, Lambson B, Modise T, Kgagudi P, York T, Westfall DH, Giorgi EE, Korber B, Anthony C, Mapengo RE, Bekker V, Domin E, Eaton A, Deng W, DeCamp A, Huang Y, Gilbert PB, Gwashu-Nyangiwe A, Thebus R, Ndabambi N, Mielke D, Mgodi N, Karuna S, Edupuganti S, Seaman MS, Corey L, Cohen MS, Hural J, McElrath MJ, Mullins JI, Montefiori D, Moore PL, Williamson C, Morris L. Neutralization profiles of HIV-1 viruses from the VRC01 Antibody Mediated Prevention (AMP) trials. PLoS Pathog 2023; 19:e1011469. [PMID: 37384759 PMCID: PMC10337935 DOI: 10.1371/journal.ppat.1011469] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 07/12/2023] [Accepted: 06/07/2023] [Indexed: 07/01/2023] Open
Abstract
The VRC01 Antibody Mediated Prevention (AMP) efficacy trials conducted between 2016 and 2020 showed for the first time that passively administered broadly neutralizing antibodies (bnAbs) could prevent HIV-1 acquisition against bnAb-sensitive viruses. HIV-1 viruses isolated from AMP participants who acquired infection during the study in the sub-Saharan African (HVTN 703/HPTN 081) and the Americas/European (HVTN 704/HPTN 085) trials represent a panel of currently circulating strains of HIV-1 and offer a unique opportunity to investigate the sensitivity of the virus to broadly neutralizing antibodies (bnAbs) being considered for clinical development. Pseudoviruses were constructed using envelope sequences from 218 individuals. The majority of viruses identified were clade B and C; with clades A, D, F and G and recombinants AC and BF detected at lower frequencies. We tested eight bnAbs in clinical development (VRC01, VRC07-523LS, 3BNC117, CAP256.25, PGDM1400, PGT121, 10-1074 and 10E8v4) for neutralization against all AMP placebo viruses (n = 76). Compared to older clade C viruses (1998-2010), the HVTN703/HPTN081 clade C viruses showed increased resistance to VRC07-523LS and CAP256.25. At a concentration of 1μg/ml (IC80), predictive modeling identified the triple combination of V3/V2-glycan/CD4bs-targeting bnAbs (10-1074/PGDM1400/VRC07-523LS) as the best against clade C viruses and a combination of MPER/V3/CD4bs-targeting bnAbs (10E8v4/10-1074/VRC07-523LS) as the best against clade B viruses, due to low coverage of V2-glycan directed bnAbs against clade B viruses. Overall, the AMP placebo viruses represent a valuable resource for defining the sensitivity of contemporaneous circulating viral strains to bnAbs and highlight the need to update reference panels regularly. Our data also suggests that combining bnAbs in passive immunization trials would improve coverage of global viruses.
Collapse
Affiliation(s)
- Nonhlanhla N. Mkhize
- National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Anna E. J. Yssel
- Institute for Infectious Diseases and Molecular Medicine, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Haajira Kaldine
- National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Rebecca T. van Dorsten
- National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- South African Medical Research Council Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Sciences University of the Witwatersrand, Johannesburg, South Africa
| | - Amanda S. Woodward Davis
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Nicolas Beaume
- Institute for Infectious Diseases and Molecular Medicine, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - David Matten
- Institute for Infectious Diseases and Molecular Medicine, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Bronwen Lambson
- National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Tandile Modise
- National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Prudence Kgagudi
- National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Talita York
- Institute for Infectious Diseases and Molecular Medicine, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Dylan H. Westfall
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Elena E. Giorgi
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Bette Korber
- Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Colin Anthony
- Institute for Infectious Diseases and Molecular Medicine, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Rutendo E. Mapengo
- National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Valerie Bekker
- National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
| | - Elizabeth Domin
- Department of Surgery, Duke University, Durham, North Carolina, United States of America
| | - Amanda Eaton
- Department of Surgery, Duke University, Durham, North Carolina, United States of America
| | - Wenjie Deng
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Allan DeCamp
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Yunda Huang
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Peter B. Gilbert
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Asanda Gwashu-Nyangiwe
- Institute for Infectious Diseases and Molecular Medicine, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Ruwayhida Thebus
- Institute for Infectious Diseases and Molecular Medicine, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Nonkululeko Ndabambi
- Institute for Infectious Diseases and Molecular Medicine, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Dieter Mielke
- Institute for Infectious Diseases and Molecular Medicine, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Department of Surgery, Duke University, Durham, North Carolina, United States of America
| | - Nyaradzo Mgodi
- University of Zimbabwe College of Health Sciences Clinical Trials Research Centre, Harare, Zimbabwe
| | - Shelly Karuna
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Srilatha Edupuganti
- Division of Infectious Diseases, Department of Medicine, Emory University, Decatur, Georgia, United States of America
| | - Michael S. Seaman
- Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Lawrence Corey
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
| | - Myron S. Cohen
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North-Carolina, United States of America
| | - John Hural
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - M. Juliana McElrath
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - James I. Mullins
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - David Montefiori
- Department of Surgery, Duke University, Durham, North Carolina, United States of America
| | - Penny L. Moore
- National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu Natal, Durban, South Africa
| | - Carolyn Williamson
- Institute for Infectious Diseases and Molecular Medicine, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu Natal, Durban, South Africa
- National Health Laboratory Service, Cape Town, South Africa
| | - Lynn Morris
- National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu Natal, Durban, South Africa
| |
Collapse
|
2
|
Characteristics of HIV-1 env genes from Chinese chronically infected donors with highly broad cross-neutralizing activity. Virology 2020; 551:16-25. [PMID: 33010671 DOI: 10.1016/j.virol.2020.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 08/17/2020] [Accepted: 08/23/2020] [Indexed: 11/24/2022]
Abstract
Knowledge about the special characteristics of HIV-1 envelope (env) glycoproteins in rare individuals developing >90% neutralization breadth in Chinese subtype B' slow progressors may provide insights for vaccine design against local viruses. We performed a cross-sectional analysis on 7 samples. We tested the neutralization breadth and geometric mean ID50 titers (GMTs) of these samples, and divided them into hBCN+ and hBCN- group according to whether their neutralization breadth >90%. We obtained env sequences in these samples through single genome amplification (SGA) assay. By comparing with hBCN-, subtype B chronically infected group (B-SP), and Chinese subtype B group (B-Database), we analyzed the characteristics of the env sequences of hBCN+ group. Longer V1 and V4 regions with more glycosylation sites were found in hBCN+ samples compared to hBCN- samples. Further analysis compared to B-SP and B-Database showed that hBCN+ group exhibited unique extra-long V1 region containing higher proportion of N-glycan sites and additional cysteines.
Collapse
|
3
|
Brandenberg OF, Rusert P, Magnus C, Weber J, Böni J, Günthard HF, Regoes RR, Trkola A. Partial rescue of V1V2 mutant infectivity by HIV-1 cell-cell transmission supports the domain's exceptional capacity for sequence variation. Retrovirology 2014; 11:75. [PMID: 25287422 PMCID: PMC4190450 DOI: 10.1186/s12977-014-0075-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 08/13/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Variable loops 1 and 2 (V1V2) of the HIV-1 envelope glycoprotein gp120 perform two key functions: ensuring envelope trimer entry competence and shielding against neutralizing antibodies. While preserving entry functionality would suggest a high need for V1V2 sequence optimization and conservation, shielding efficacy is known to depend on a high flexibility of V1V2 giving rise to its substantial sequence variability. How entry competence of the trimer is maintained despite the continuous emergence of antibody escape mutations within V1V2 has not been resolved. Since HIV cell-cell transmission is considered a highly effective means of virus dissemination, we investigated whether cell-cell transmission may serve to enhance infectivity of V1V2 variants with debilitated free virus entry. RESULTS In a detailed comparison of wt and V1V2 mutant envelopes, V1V2 proved to be a key factor in ascertaining free virus infectivity, with V1V2 mutants displaying significantly reduced trimer integrity. Despite these defects, cell-cell transmission was able to partially rescue infectivity of V1V2 mutant viruses. We identified two regions, encompassing amino acids 156 to 160 (targeted by broadly neutralizing antibodies) and 175 to 180 (encompassing the α4β7 binding site) which were particularly prone to free virus infectivity loss upon mutation but maintained infectivity in cell-cell transmission. Of note, V1V2 antibody shielding proved important during both free virus infection and cell-cell transmission. CONCLUSIONS Based on our data we propose a model for V1V2 evolution that centers on cell-cell transmission as a salvage pathway for virus replication. Escape from antibody neutralization may frequently result in V1V2 mutations that reduce free virus infectivity. Cell-cell transmission could provide these escape viruses with sufficiently high replication levels that enable selection of compensatory mutations, thereby restoring free virus infectivity while ensuring antibody escape. Thus, our study highlights the need to factor in cell-cell transmission when considering neutralization escape pathways of HIV-1.
Collapse
|
4
|
Totrov M. Estimated secondary structure propensities within V1/V2 region of HIV gp120 are an important global antibody neutralization sensitivity determinant. PLoS One 2014; 9:e94002. [PMID: 24705879 PMCID: PMC3976368 DOI: 10.1371/journal.pone.0094002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 03/10/2014] [Indexed: 11/22/2022] Open
Abstract
Background Neutralization sensitivity of HIV-1 virus to antibodies and anti-sera varies greatly between the isolates. Significant role of V1/V2 domain as a global neutralization sensitivity regulator has been suggested. Recent X-ray structures revealed presence of well-defined tertiary structure within this domain but also demonstrated partial disorder and conformational heterogeneity. Methods Correlations of neutralization sensitivity with the conformational propensities for beta-strand and alpha-helix formation over the entire folded V1/V2 domain as well as within sliding 5-residue window were investigated. Analysis was based on a set of neutralization data for 106 HIV isolates for which consistent neutralization sensitivity measurements against multiple pools of human immune sera have been previously reported. Results Significant correlation between beta-sheet formation propensity of the folded segments of V1/V2 domain and neutralization sensitivity was observed. Strongest correlation peaks localized to the beta-strands B and C. Correlation persisted when subsets of HIV isolates belonging to clades B, C and circulating recombinant form BC where analyzed individually or in combinations. Conclusions Observed correlations suggest that stability of the beta-sheet structure and/or degree of structural disorder in the V1/V2 domain is an important determinant of the global neutralization sensitivity of HIV-1 virus. While specific mechanism is to yet to be investigated, plausible hypothesis is that less ordered V1/V2s may have stronger masking effect on various neutralizing epitopes, perhaps effectively occupying larger volume and thereby occluding antibody access.
Collapse
Affiliation(s)
- Maxim Totrov
- Molsoft LLC, San Diego, California, United States of America
- * E-mail:
| |
Collapse
|
5
|
Davenport TM, Guttman M, Guo W, Cleveland B, Kahn M, Hu SL, Lee KK. Isolate-specific differences in the conformational dynamics and antigenicity of HIV-1 gp120. J Virol 2013; 87:10855-73. [PMID: 23903848 PMCID: PMC3807424 DOI: 10.1128/jvi.01535-13] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 07/25/2013] [Indexed: 01/06/2023] Open
Abstract
The HIV-1 envelope glycoprotein (Env) mediates viral entry into host cells and is the sole target of neutralizing antibodies. Much of the sequence diversity in the HIV-1 genome is concentrated within Env, particularly within its gp120 surface subunit. While dramatic functional diversity exists among HIV-1 Env isolates-observable even in the context of monomeric gp120 proteins as differences in antigenicity and immunogenicity-we have little understanding of the structural features that distinguish Env isolates and lead to isolate-specific functional differences, as crystal structures of truncated gp120 "core" proteins from diverse isolates reveal a high level of structural conservation. Because gp120 proteins are used as prospective vaccine immunogens, it is critical to understand the structural factors that influence their reactivity with antibodies. Here, we studied four full-length, glycosylated gp120 monomers from diverse HIV-1 isolates by using small-angle X-ray scattering (SAXS) to probe the overall subunit morphology and hydrogen/deuterium-exchange with mass spectrometry (HDX-MS) to characterize the local structural order of each gp120. We observed that while the overall subunit architecture was similar among isolates by SAXS, dramatic isolate-specific differences in the conformational stability of gp120 were evident by HDX-MS. These differences persisted even with the CD4 receptor bound. Furthermore, surface plasmon resonance (SPR) and enzyme-linked immunosorbance assays (ELISAs) showed that disorder was associated with poorer recognition by antibodies targeting conserved conformational epitopes. These data provide additional insight into the structural determinants of gp120 antigenicity and suggest that conformational dynamics should be considered in the selection and design of optimized Env immunogens.
Collapse
Affiliation(s)
| | | | - Wenjin Guo
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA
| | - Brad Cleveland
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA
| | - Maria Kahn
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA
| | - Shiu-Lok Hu
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA
- Washington National Primate Research Center, Seattle, Washington, USA
| | - Kelly K. Lee
- Department of Global Health
- Department of Medicinal Chemistry
| |
Collapse
|
6
|
Drummer HE, Hill MK, Maerz AL, Wood S, Ramsland PA, Mak J, Poumbourios P. Allosteric modulation of the HIV-1 gp120-gp41 association site by adjacent gp120 variable region 1 (V1) N-glycans linked to neutralization sensitivity. PLoS Pathog 2013; 9:e1003218. [PMID: 23592978 PMCID: PMC3616969 DOI: 10.1371/journal.ppat.1003218] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 01/15/2013] [Indexed: 12/28/2022] Open
Abstract
The HIV-1 gp120-gp41 complex, which mediates viral fusion and cellular entry, undergoes rapid evolution within its external glycan shield to enable escape from neutralizing antibody (NAb). Understanding how conserved protein determinants retain functionality in the context of such evolution is important for their evaluation and exploitation as potential drug and/or vaccine targets. In this study, we examined how the conserved gp120-gp41 association site, formed by the N- and C-terminal segments of gp120 and the disulfide-bonded region (DSR) of gp41, adapts to glycan changes that are linked to neutralization sensitivity. To this end, a DSR mutant virus (K601D) with defective gp120-association was sequentially passaged in peripheral blood mononuclear cells to select suppressor mutations. We reasoned that the locations of suppressors point to structural elements that are functionally linked to the gp120-gp41 association site. In culture 1, gp120 association and viral replication was restored by loss of the conserved glycan at Asn136 in V1 (T138N mutation) in conjunction with the L494I substitution in C5 within the association site. In culture 2, replication was restored with deletion of the N139INN sequence, which ablates the overlapping Asn141-Asn142-Ser-Ser potential N-linked glycosylation sequons in V1, in conjunction with D601N in the DSR. The 136 and 142 glycan mutations appeared to exert their suppressive effects by altering the dependence of gp120-gp41 interactions on the DSR residues, Leu593, Trp596 and Lys601. The 136 and/or 142 glycan mutations increased the sensitivity of HIV-1 pseudovirions to the glycan-dependent NAbs 2G12 and PG16, and also pooled IgG obtained from HIV-1-infected individuals. Thus adjacent V1 glycans allosterically modulate the distal gp120-gp41 association site. We propose that this represents a mechanism for functional adaptation of the gp120-gp41 association site to an evolving glycan shield in a setting of NAb selection. The envelope glycoprotein gp120-gp41 complex of HIV-1 mediates receptor attachment and virus-cell membrane fusion, leading to cellular entry. A shield of asparagine-linked oligosaccharides occludes the gp120-gp41 protein surface and evolution of this glycan shield provides a means for evading circulating neutralizing antibody. Here we examined how conserved structural elements of the glycoprotein complex, in particular the gp120-gp41 association site, retain functionality in the context of glycan shield evolution. This information is important for the evaluation and exploitation of such conserved functional determinants as potential drug and/or vaccine targets. Our data indicate that the loss of either of 2 adjacent glycans in variable region 1 of gp120 leads to changes in local and remote glycan-dependent epitopes and that this is linked to a remodelling of gp120-gp41 interactions in order to maintain a functional gp120-gp41 complex. We propose that this represents a mechanism for the functional adaptation of the gp120-gp41 association site to an evolving glycan shield in a setting of neutralizing antibody selection.
Collapse
Affiliation(s)
- Heidi E. Drummer
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
- Department of Microbiology and Immunology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Melissa K. Hill
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - Anne L. Maerz
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - Stephanie Wood
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - Paul A. Ramsland
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
- Department of Immunology, Monash University, Alfred Medical Research and Education Precinct, Melbourne, Victoria, Australia
- Department of Surgery, Austin Health, The University of Melbourne, Heidelberg, Victoria, Australia
| | - Johnson Mak
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
- Deakin University School of Medicine, Geelong, Victoria, Australia
| | - Pantelis Poumbourios
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
- * E-mail:
| |
Collapse
|
7
|
|
8
|
Rusert P, Krarup A, Magnus C, Brandenberg OF, Weber J, Ehlert AK, Regoes RR, Günthard HF, Trkola A. Interaction of the gp120 V1V2 loop with a neighboring gp120 unit shields the HIV envelope trimer against cross-neutralizing antibodies. ACTA ACUST UNITED AC 2011; 208:1419-33. [PMID: 21646396 PMCID: PMC3135368 DOI: 10.1084/jem.20110196] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Structure–function analysis and mathematical modeling reveal insight into the mechanisms through which conserved HIV-1 gp120 epitopes are masked in the HIV-1 envelope trimer. The HIV-1 envelope trimer adopts a quaternary conformation that effectively shields neutralization-sensitive domains and thus represents a major obstacle for natural and vaccine-elicited antibody responses. By using a structure–function analysis based on a specifically devised mathematical model, we demonstrate in this study that protection from neutralization is enforced by intersubunit contact between the variable loops 1 and 2 (V1V2) and domains of neighboring gp120 subunits in the trimer encompassing the V3 loop. Our data are consistent with an interaction of the V1V2 and V3 loop at the spike apex as proposed by cryoelectron tomography experiments. By defining the orientation of the V1V2 loop within the trimer toward the neighboring gp120 subunit’s V3 loop, our data close an important gap in the understanding of the architecture of the trimeric spike. Knowledge on how the V1V2 barrier functions in the context of the trimer to mask conserved epitopes on gp120 may aid future vaccine design.
Collapse
Affiliation(s)
- Peter Rusert
- Institute of Medical Virology, University Hospital Zurich; University of Zurich, 8006 Zurich, Switzerland
| | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Longer V1V2 region with increased number of potential N-linked glycosylation sites in the HIV-1 envelope glycoprotein protects against HIV-specific neutralizing antibodies. J Virol 2011; 85:6986-95. [PMID: 21593147 DOI: 10.1128/jvi.00268-11] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) has the ability to adapt to the host environment by escaping from host immune responses. We previously observed that escape from humoral immunity, both at the individual and at a population level, coincided with longer variable loops and an increased number of potential N-linked glycosylation sites (PNGS) in the viral envelope glycoprotein (Env) and, in particular, in variable regions 1 and 2 (V1V2). Here, we provide several lines of evidence for the role of V1V2 in the resistance of HIV-1 to neutralizing antibodies. First, we determined that the increasing neutralization resistance of a reference panel of tier-categorized neutralization-sensitive and -resistant HIV-1 variants coincided with a longer V1V2 loop containing more PNGS. Second, an exchange of the different variable regions of Env from a neutralization-sensitive HIV-1 variant into a neutralization-resistant escape variant from the same individual revealed that the V1V2 loop is a strong determinant for sensitivity to autologous-serum neutralization. Third, exchange of the V1V2 loop of neutralization-sensitive HIV-1 variants from historical seroconverters with the V1V2 loop of neutralization-resistant HIV-1 variants from contemporary seroconverters decreased the neutralization sensitivity to CD4-binding site-directed antibodies. Overall, we demonstrate that an increase in the length of the V1V2 loop and/or the number of PNGS in that same region of the HIV-1 envelope glycoprotein is directly involved in the protection of HIV-1 against HIV-specific neutralizing antibodies, possibly by shielding underlying epitopes in the envelope glycoprotein from antibody recognition.
Collapse
|
10
|
Sterjovski J, Churchill MJ, Roche M, Ellett A, Farrugia W, Wesselingh SL, Cunningham AL, Ramsland PA, Gorry PR. CD4-binding site alterations in CCR5-using HIV-1 envelopes influencing gp120-CD4 interactions and fusogenicity. Virology 2011; 410:418-28. [PMID: 21216423 DOI: 10.1016/j.virol.2010.12.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 11/24/2010] [Accepted: 12/06/2010] [Indexed: 11/30/2022]
Abstract
CD4-binding site (CD4bs) alterations in gp120 contribute to different pathophysiological phenotypes of CCR5-using (R5) HIV-1 strains, but the potential structural basis is unknown. Here, we characterized functionally diverse R5 envelope (Env) clones (n=16) to elucidate potential structural alterations within the gp120 CD4bs that influence Env function. Initially, we showed that the magnitude of gp120-CD4-binding correlates with increased fusogenicity and reduced CD4 dependence. Analysis of three-dimensional gp120 structural models revealed two CD4bs variants, D279 and N362, that were associated with reduced CD4 dependence. Further structural analysis showed that a wider aperture of the predicted CD4bs cavity, as constrained by the inner-most atoms at the gp120 V1V2 stem and the V5 loop, was associated with amino acid alterations within V5 and correlated with increased gp120-CD4 binding and increased fusogenicity. Our results provide evidence that the gp120 V5 loop may alter CD4bs conformation and contribute to increased gp120-CD4 interactions and Env fusogenicity.
Collapse
|
11
|
Siddappa NB, Watkins JD, Wassermann KJ, Song R, Wang W, Kramer VG, Lakhashe S, Santosuosso M, Poznansky MC, Novembre FJ, Villinger F, Else JG, Montefiori DC, Rasmussen RA, Ruprecht RM. R5 clade C SHIV strains with tier 1 or 2 neutralization sensitivity: tools to dissect env evolution and to develop AIDS vaccines in primate models. PLoS One 2010; 5:e11689. [PMID: 20657739 PMCID: PMC2908149 DOI: 10.1371/journal.pone.0011689] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 06/18/2010] [Indexed: 11/21/2022] Open
Abstract
Background HIV-1 clade C (HIV-C) predominates worldwide, and anti-HIV-C vaccines are urgently needed. Neutralizing antibody (nAb) responses are considered important but have proved difficult to elicit. Although some current immunogens elicit antibodies that neutralize highly neutralization-sensitive (tier 1) HIV strains, most circulating HIVs exhibiting a less sensitive (tier 2) phenotype are not neutralized. Thus, both tier 1 and 2 viruses are needed for vaccine discovery in nonhuman primate models. Methodology/Principal Findings We constructed a tier 1 simian-human immunodeficiency virus, SHIV-1157ipEL, by inserting an “early,” recently transmitted HIV-C env into the SHIV-1157ipd3N4 backbone [1] encoding a “late” form of the same env, which had evolved in a SHIV-infected rhesus monkey (RM) with AIDS. SHIV-1157ipEL was rapidly passaged to yield SHIV-1157ipEL-p, which remained exclusively R5-tropic and had a tier 1 phenotype, in contrast to “late” SHIV-1157ipd3N4 (tier 2). After 5 weekly low-dose intrarectal exposures, SHIV-1157ipEL-p systemically infected 16 out of 17 RM with high peak viral RNA loads and depleted gut CD4+ T cells. SHIV-1157ipEL-p and SHIV-1157ipd3N4 env genes diverge mostly in V1/V2. Molecular modeling revealed a possible mechanism for the increased neutralization resistance of SHIV-1157ipd3N4 Env: V2 loops hindering access to the CD4 binding site, shown experimentally with nAb b12. Similar mutations have been linked to decreased neutralization sensitivity in HIV-C strains isolated from humans over time, indicating parallel HIV-C Env evolution in humans and RM. Conclusions/Significance SHIV-1157ipEL-p, the first tier 1 R5 clade C SHIV, and SHIV-1157ipd3N4, its tier 2 counterpart, represent biologically relevant tools for anti-HIV-C vaccine development in primates.
Collapse
Affiliation(s)
- Nagadenahalli B. Siddappa
- Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jennifer D. Watkins
- Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | | | - Ruijiang Song
- Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Wendy Wang
- Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Victor G. Kramer
- Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Samir Lakhashe
- Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Michael Santosuosso
- Harvard Medical School, Boston, Massachusetts, United States of America
- Partners AIDS Research Center and Infectious Diseases Medicine, Massachusetts General Hospital (East), Charlestown, Massachusetts, United States of America
| | - Mark C. Poznansky
- Harvard Medical School, Boston, Massachusetts, United States of America
- Partners AIDS Research Center and Infectious Diseases Medicine, Massachusetts General Hospital (East), Charlestown, Massachusetts, United States of America
| | - Francis J. Novembre
- Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
- Department of Microbiology and Immunology, Emory University, Atlanta, Georgia, United States of America
| | - François Villinger
- Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
- Division of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia, United States of America
| | - James G. Else
- Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
- Division of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia, United States of America
| | - David C. Montefiori
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Robert A. Rasmussen
- Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ruth M. Ruprecht
- Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
| |
Collapse
|
12
|
Alterations in the immunogenic properties of soluble trimeric human immunodeficiency virus type 1 envelope proteins induced by deletion or heterologous substitutions of the V1 loop. J Virol 2010; 84:9932-46. [PMID: 20660181 DOI: 10.1128/jvi.00868-10] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HIV-1 gp140 envelope immunogens express conserved epitopes that are targeted by broadly cross-reactive neutralizing antibodies, but they fail to elicit similar antibodies upon immunization. The poor immunogenicity of conserved epitopes on gp140 could be linked to the high immunogenicity of variable Env regions on such constructs. Previous studies have shown that the first hypervariable region (V1 loop) is immunogenic on soluble gp140s but elicits type-specific antibodies. To address issues related to the high immunogenicity of the V1 loop, two conceptually opposite approaches were tested. In the first approach, we eliminated the V1 loop from our gp140 construct and examined how V1 deletion altered the immunogenic properties of other Env regions. In the second approach, we took advantage of the high immunogenicity of the V1 loop and engrafted four diverse V1 loops onto a common gp140 Env "scaffold." These four scaffolds were used as a cocktail of immunogens to elicit diverse anti-V1 antibodies, under the hypothesis that eliciting diverse anti-V1 antibodies would expand the neutralizing breadth of immune sera. Our study indicates that three of four heterologous V1 loops were immunogenic on the common Env backbone "scaffold," but heterologous anti-V1 neutralizing responses were observed in only one case. Both types of V1 modification dampened the immunogenicity of the V3 loop, differentially altered the immunogenicity of the transmembrane gp41 subunit, and altered the relative immunogenicities of unknown Env regions, including potentially the CD4-binding site (CD4-bs) and trimer-specific targets, which elicited cross-reactive neutralizing antibodies but of limited breadth.
Collapse
|
13
|
Unravelling the antigenic landscape of the HIV-1 subtype A envelope of an individual with broad cross-neutralizing antibodies using phage display peptide libraries. J Virol Methods 2010; 169:95-102. [PMID: 20637241 DOI: 10.1016/j.jviromet.2010.07.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 06/29/2010] [Accepted: 07/05/2010] [Indexed: 12/26/2022]
Abstract
Broad cross-neutralizing antibodies from persons infected with HIV-1 target a variety of epitopes. Identification of these HIV-1 epitopes may result in an optimal panel of antigenic peptides to be included in a prophylactic vaccine. Phage display peptide libraries were used to unravel the antigenic landscape of an individual (ITM1) infected with HIV-1 subtype A with broad cross-neutralizing antibodies. A stringent selection strategy resulted in the identification of 60 unique HIV-1 peptide phage, which were subjected to sequence analysis and mapped onto the ITM1 envelope sequences. Four groups of peptide phages were found: the first group (n=11) were similar with the tip of the V3 loop (KxxHxGPxxxF); the second group (n=11) represented the gp41 principal immunodominant domain (CxGxLxCTxNxP); the third group (n=16) could be localized in the V2 loop (KxxxHxxxY); and the fourth group (n=22) mimicked a conformational epitope (Hxx(S)/(T)NxK). All but the V2-binding antibodies were conserved over the 11 years of follow-up. A neutralization inhibition assay revealed the contribution of the V3 antibodies to the neutralizing capacity of the ITM1 plasma. Overall, the ITM1 immunogenic landscape was mapped and a part of the origin of this broad cross-neutralizing activity was demonstrated.
Collapse
|
14
|
Immunization with wild-type or CD4-binding-defective HIV-1 Env trimers reduces viremia equivalently following heterologous challenge with simian-human immunodeficiency virus. J Virol 2010; 84:9086-95. [PMID: 20610729 DOI: 10.1128/jvi.01015-10] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We recently reported that rhesus macaques inoculated with CD4-binding-competent and CD4-binding-defective soluble YU2-derived HIV-1 envelope glycoprotein (Env) trimers in adjuvant generate comparable levels of Env-specific binding antibodies (Abs) and T cell responses. We also showed that Abs directed against the Env coreceptor binding site (CoRbs) were elicited only in animals immunized with CD4-binding-competent trimers and not in animals immunized with CD4-binding-defective trimers, indicating that a direct interaction between Env and CD4 occurs in vivo. To investigate both the overall consequences of in vivo Env-CD4 interactions and the elicitation of CoRbs-directed Abs for protection against heterologous simian-human immunodeficiency virus (SHIV) challenge, we exposed rhesus macaques immunized with CD4-binding-competent and CD4-binding-defective trimers to the CCR5-tropic SHIV-SF162P4 challenge virus. Compared to unvaccinated controls, all vaccinated animals displayed improved control of plasma viremia, independent of the presence or absence of CoRbs-directed Abs prior to challenge. Immunization resulted in plasma responses that neutralized the heterologous SHIV challenge stock in vitro, with similar neutralizing Ab titers elicited by the CD4-binding-competent and CD4-binding-defective trimers. The neutralizing responses against both the SHIV-SF162P4 stock and a recombinant virus pseudotyped with a cloned SHIV-SF162P4-derived Env were significantly boosted by the SHIV challenge. Collectively, these results suggest that the capacity of soluble Env trimers to interact with primate CD4 in vivo and to stimulate the production of moderate titers of CoRbs-directed Abs did not influence the magnitude of the neutralizing Ab recall response after viral challenge or the subsequent control of viremia in this heterologous SHIV challenge model.
Collapse
|
15
|
Abstract
Licensed vaccines against viral diseases generate antibodies that neutralize the infecting virus and protect against infection or disease. Similarly, an effective vaccine against HIV-1 will likely need to induce antibodies that prevent initial infection of host cells or that limit early events of viral dissemination. Such antibodies must target the surface envelope glycoproteins of HIV-1, which are highly variable in sequence and structure. The first subunit vaccines to enter clinical trails were safe and immunogenic but unable to elicit antibodies that neutralized most circulating strains of HIV-1. However, potent virus neutralizing antibodies (NAbs) can develop during the course of HIV-1 infection, and this is the type of antibody response that researchers seek to generate with a vaccine. Thus, current vaccine design efforts have focused on a more detailed understanding of these broadly neutralizing antibodies and their epitopes to inform the design of improved vaccines.
Collapse
Affiliation(s)
- John R Mascola
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
| | | |
Collapse
|
16
|
Abstract
PURPOSE OF REVIEW Effective vaccine-elicited immunity against HIV-1 infection will likely require broadly neutralizing antibodies to interrupt the fusion-promoting functions of the viral envelope glycoprotein spikes. Efforts in this area have, however, been fraught with challenges. The handful of existing broadly neutralizing monoclonal antibodies has provided information on some of the virus' sites of vulnerability, fueling a decade of structure-informed vaccine design. The fact that very few bnmAbs have been recovered to date illustrates the poor immunogenicity of these epitopes. Recognizing that progress may require more basic information, there has been a notable shift in the field toward identifying new chinks in HIV-1's armor. These efforts are based on the observation that some infected patients develop exceptionally broad serum neutralizing antibodies responses, a better understanding of which would be valuable for vaccine efforts aimed at eliciting similar specificities. RECENT FINDINGS New mapping methodologies are now providing an appreciation of the incidence of specificities similar to the existing known bnmAbs as well as some intriguing insights into novel specificities. SUMMARY The new information emerging from mapping efforts should help to sharpen efforts to isolate new bnmAbs and moreover, may provide crucial information for the rational design of novel vaccine candidates.
Collapse
|
17
|
Blish CA, Sather DN, Sellhorn G, Stamatatos L, Sun Y, Srivastava I, Barnett SW, Cleveland B, Overbaugh J, Hu SL. Comparative immunogenicity of subtype a Human Immunodeficiency Virus type 1 envelope exhibiting differential exposure of conserved neutralization epitopes. J Virol 2010; 84:2573-84. [PMID: 20015987 PMCID: PMC2820908 DOI: 10.1128/jvi.01687-09] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Accepted: 12/07/2009] [Indexed: 11/20/2022] Open
Abstract
Development of broadly cross-reactive neutralizing antibodies (NAbs) remains a major goal of HIV-1 vaccine development, but most candidate envelope immunogens have had limited ability to cross-neutralize heterologous strains. To evaluate the immunogenicity of subtype A variants of HIV-1, rabbits were immunized with pairs of closely related subtype A envelopes from the same individual. In each immunogen pair, one variant was readily neutralized by a variety of monoclonal antibodies and plasma antibodies, while the other was neutralization resistant, suggesting differences in the exposures of key epitopes. The breadth of the antibody response was evaluated against subtype A, B, C, and D variants of HIV-1. The specificity of the immunogen-derived neutralizing antibody response was also compared to that of the infected individuals from whom these variants were cloned. None of the immunogens produced broad neutralizing antibodies in immunized animals, and most of the neutralizing antibodies were directed to the variable loops, particularly the V3 loop. No detectable antibodies to either of the potentially exposed conserved epitopes, the membrane proximal external region, or the CD4 binding site were found with immunized rabbits. In contrast, relatively little of the neutralizing activity within the plasma samples of the infected individuals was directed to linear epitopes within the variable loops. These data indicate that immunogens designed to expose conserved regions did not enhance generation of broadly neutralizing antibodies in comparison with the immunogens that failed to expose those regions using this immunization approach.
Collapse
Affiliation(s)
- Catherine A Blish
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Dieltjens T, Loots N, Vereecken K, Grupping K, Heyndrickx L, Bottieau E, Vanham G, Davis D, Janssens W. HIV type 1 subtype A envelope genetic evolution in a slow progressing individual with consistent broadly neutralizing antibodies. AIDS Res Hum Retroviruses 2009; 25:1165-9. [PMID: 19886837 DOI: 10.1089/aid.2008.0161] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Studies of viruses taken from individuals with broad cross-neutralizing antibodies against primary isolates may reveal novel antibody specificities and their associated epitopes that could be useful for immunogen design. We report on the Env antigenic variability of a slow progressing HIV-1 subtype A-infected donor with consistent broad cross-neutralizing antibodies during the second decade of disease progression after vertical transmission. The Env evolution is characterized by a genetic shift to variants with altered V1-V5 loop sequences, marked by consecutive changes in V1, V4-V5, and C3 and largely conserved V2 and V3 loop sequences. Major V1 Env sequence expansion, variation by a duplication event, and cumulative addition of cysteine residues and potential N-glycosylation sites over time may contribute to escape from antibody pressure directed to Env receptor domains by changing the exposure of neutralization-sensitive epitopes. Conservation of functional epitopes may correlate with the continued presence of broad cross-neutralizing antibodies.
Collapse
Affiliation(s)
- Tessa Dieltjens
- Department of Microbiology, Unit of Virology, Institute of Tropical Medicine, Antwerp, Belgium
| | - Nathalie Loots
- Department of Microbiology, Unit of Virology, Institute of Tropical Medicine, Antwerp, Belgium
| | - Katleen Vereecken
- Department of Microbiology, Unit of Virology, Institute of Tropical Medicine, Antwerp, Belgium
| | - Katrijn Grupping
- Department of Microbiology, Unit of Virology, Institute of Tropical Medicine, Antwerp, Belgium
| | - Leo Heyndrickx
- Department of Microbiology, Unit of Virology, Institute of Tropical Medicine, Antwerp, Belgium
| | - Emmanuel Bottieau
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Guido Vanham
- Department of Microbiology, Unit of Virology, Institute of Tropical Medicine, Antwerp, Belgium
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - David Davis
- Department of Virology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Wouter Janssens
- Department of Microbiology, Unit of Virology, Institute of Tropical Medicine, Antwerp, Belgium
| |
Collapse
|
19
|
Cruz LJ, Cabrales A, Iglesias E, Aguilar JC, González LJ, Reyes O. Enhanced immunogenicity and cross-reactivity of HIV-1 V3-peptide and multiple antigen peptides conjugated to distinct carrier proteins. Int Immunopharmacol 2009; 9:1452-9. [DOI: 10.1016/j.intimp.2009.08.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2009] [Revised: 07/26/2009] [Accepted: 08/31/2009] [Indexed: 10/20/2022]
|
20
|
Abstract
PURPOSE OF REVIEW It has long been known that autologous neutralizing antibodies (AnAbs) exert pressure on the envelope of HIV, resulting in neutralization escape. However, recently, progress has been made in uncovering the precise targets of these potent early antibodies. RECENT FINDINGS AnAbs primarily target variable regions of the HIV-1 envelope, explaining the strain-specificity of these antibodies. Despite high neutralizing potential and cross-reactivity, anti-V3 antibodies do not contribute to autologous neutralization. The V1V2 is commonly immunogenic in early HIV-1 and simian human immunodeficiency virus infections, though the nature of these epitopes remains to be determined. In subtype C viruses, the C3 region is a neutralization target, possibly as a result of its more exposed and amphipathic structure. Autologous neutralization appears to be mediated by very few AnAb specificities that develop sequentially suggesting the possibility of immunological hierarchies for both binding and neutralizing antibodies. The role of AnAbs in preventing superinfection and in restricting virus replication is reexamined in the context of recent data. SUMMARY New studies have greatly contributed toward our understanding of the specificities mediating autologous neutralization and highlighted potential vulnerabilities on transmitted viruses. However, the contribution of AnAbs to the development of neutralization breadth remains to be characterized.
Collapse
Affiliation(s)
- Penny L Moore
- AIDS Virus Research Unit, National Institute for Communicable Diseases, Johannesburg, South Africa.
| | | | | |
Collapse
|
21
|
Introduction of exogenous epitopes in the variable regions of the human immunodeficiency virus type 1 envelope glycoprotein: effect on viral infectivity and the neutralization phenotype. J Virol 2009; 83:7883-93. [PMID: 19494007 DOI: 10.1128/jvi.00582-09] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this study we examined whether human immunodeficiency virus type 1 (HIV-1) is equally susceptible to neutralization by a given antibody when the epitope of this antibody is introduced at different positions within the viral envelope glycoprotein (Env). To this end, we introduced two exogenous "epitope tags" at different locations within three major Env regions in two distinct HIV-1 isolates. We examined how the introduction of the exogenous epitopes affects Env expression, Env incorporation into virions, Env fusogenic potential, and viral susceptibility to neutralization. Our data indicate that even within the same Env region, the exact positioning of the epitope impacts the susceptibility of the virus to neutralization by the antibody that binds to that epitope. Our data also indicate that even if the same epitope is introduced in the exact same position on two different Envs, its exposure and, as a result, the neutralization susceptibility of the virus, can be very different. In contrast to the findings of previous studies conducted with HIV-1 isolates other than those used here, but in agreement with results obtained with simian immunodeficiency virus, we observed that tagging of the fourth variable region of Env (V4) did not result in neutralization by the anti-tag antibodies. Our data indicate that epitopes in V4 are not properly exposed within the functional HIV-1 trimeric Env spike, suggesting that V4 may not be a good target for vaccine-elicited neutralizing antibodies.
Collapse
|
22
|
Lynch RM, Shen T, Gnanakaran S, Derdeyn CA. Appreciating HIV type 1 diversity: subtype differences in Env. AIDS Res Hum Retroviruses 2009; 25:237-48. [PMID: 19327047 DOI: 10.1089/aid.2008.0219] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) group M is responsible for the current AIDS pandemic and exhibits exceedingly high levels of viral genetic diversity around the world, necessitating categorization of viruses into distinct lineages, or subtypes. These subtypes can differ by around 35% in the envelope (Env) glycoproteins of the virus, which are displayed on the surface of the virion and are targets for both neutralizing antibody and cell-mediated immune responses. This diversity reflects the remarkable ability of the virus to adapt to selective pressures, the bulk of which is applied by the host immune response, and represents a serious obstacle for developing an effective vaccine with broad coverage. Thus, it is important to understand the underlying biological consequences of intersubtype diversity. Recent studies have revealed that some of the HIV-1 subtypes exhibit phenotypic differences stemming from subtle changes in Env structure, particularly within the highly immunogenic V3 domain, which participates directly in viral entry. This review will therefore explore current research that describes subtype differences in Env at the genetic and phenotypic level, focusing in particular on V3, and highlighting recent discoveries about the unique features of subtype C Env, which is the most globally prevalent subtype.
Collapse
Affiliation(s)
- Rebecca M. Lynch
- Immunology and Molecular Pathogenesis Program, Emory University, Atlanta, Georgia 30329
| | - Tongye Shen
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
| | - S. Gnanakaran
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545
| | - Cynthia A. Derdeyn
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia 30329
- Yerkes National Primate Research Center, Emory University, Atlanta, Georgia 30329
- Emory Vaccine Center, Emory University, Atlanta, Georgia 30329
| |
Collapse
|
23
|
Importance of the V1/V2 loop region of simian-human immunodeficiency virus envelope glycoprotein gp120 in determining the strain specificity of the neutralizing antibody response. J Virol 2008; 82:11054-65. [PMID: 18768967 DOI: 10.1128/jvi.01341-08] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Plasma samples from individuals infected with human immunodeficiency virus type 1 (HIV-1) are known to be highly strain specific in their ability to neutralize HIV-1 infectivity. Such plasma samples exhibit significant neutralizing activity against autologous HIV-1 isolates but typically exhibit little or no activity against heterologous strains, although some cross-neutralizing activity can develop late in infection. Monkeys infected with the simian-human immunodeficiency virus (SHIV) clone DH12 generated antibodies that neutralized SHIV DH12, but not SHIV KB9. Conversely, antibodies from monkeys infected with the SHIV clone KB9 neutralized SHIV KB9, but not SHIV DH12. To investigate the role of the variable loops of the HIV-1 envelope glycoprotein gp120 in determining this strain specificity, variable loops 1 and 2 (V1/V2), V3, or V4 were exchanged individually or in combination between SHIV DH12 and SHIV KB9. Despite the fact that both parental viruses exhibited significant infectivity and good replication in the cell lines examined, 3 of the 10 variable-loop chimeras exhibited such poor infectivity that they could not be used further for neutralization assays. These results indicate that a variable loop that is functional in the context of one particular envelope background will not necessarily function within another. The remaining seven replication-competent chimeras allowed unambiguous assignment of the sequences principally responsible for the strain specificity of the neutralizing activity present in SHIV-positive plasma. Exchange of the V1/V2 loop sequences conferred a dominant loss of sensitivity to neutralization by autologous plasma and a gain of sensitivity to neutralization by heterologous plasma. Substitution of V3 or V4 had little or no effect on the sensitivity to neutralization. These data demonstrate that the V1/V2 region of HIV-1 gp120 is principally responsible for the strain specificity of the neutralizing antibody response in monkeys infected with these prototypic SHIVs.
Collapse
|
24
|
Characterization of neutralizing antibody responses elicited by clade A envelope immunogens derived from early transmitted viruses. J Virol 2008; 82:5912-21. [PMID: 18400850 DOI: 10.1128/jvi.00389-08] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The vast majority of studies with candidate immunogens based on the human immunodeficiency virus envelope (Env) have been conducted with Env proteins derived from clade B viruses isolated during chronic infection. Whether non-clade B Env protein immunogens will elicit antibodies with epitope specificities that are similar to those of antibodies elicited by clade B Envs and whether the antibodies elicited by Envs derived from early transmitted viruses will be similar to those elicited by Envs derived from viruses isolated during chronic infection are currently unknown. Here we performed immunizations with four clade A Envs, cloned directly from the peripheral blood of infected individuals during acute infection, which differed in lengths and extents of glycosylation. The antibody responses elicited by these four Envs were compared to each other and to those elicited by a well-characterized clade B Env immunogen derived from the SF162 virus, which was isolated during chronic infection. Only one clade A Env, the one with the fewer glycosylation sites, elicited homologous neutralizing antibodies (NAbs); these did not target the V1, V2, or V3 regions. In contrast, all four clade A Envs elicited anti-V3 NAbs against "easy-to-neutralize" clade B and clade A isolates, irrespective of the variable region length and extent of glycosylation of the Env used as an immunogen. These anti-V3 NAbs did not access their epitopes on homologous and heterologous clade A, or B, neutralization-resistant viruses. The length and extent of glycosylation of the variable regions on the clade A Env immunogens tested did not affect the breadth of the elicited NAbs. Our data also indicate that the development of cross-reactive NAbs against clade A viruses faces similar hurdles to the development of cross-reactive anti-clade B NAbs.
Collapse
|