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Schiffner T, Pallesen J, Russell RA, Dodd J, de Val N, LaBranche CC, Montefiori D, Tomaras GD, Shen X, Harris SL, Moghaddam AE, Kalyuzhniy O, Sanders RW, McCoy LE, Moore JP, Ward AB, Sattentau QJ. Structural and immunologic correlates of chemically stabilized HIV-1 envelope glycoproteins. PLoS Pathog 2018; 14:e1006986. [PMID: 29746590 PMCID: PMC5944921 DOI: 10.1371/journal.ppat.1006986] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 03/21/2018] [Indexed: 11/19/2022] Open
Abstract
Inducing broad spectrum neutralizing antibodies against challenging pathogens such as HIV-1 is a major vaccine design goal, but may be hindered by conformational instability within viral envelope glycoproteins (Env). Chemical cross-linking is widely used for vaccine antigen stabilization, but how this process affects structure, antigenicity and immunogenicity is poorly understood and its use remains entirely empirical. We have solved the first cryo-EM structure of a cross-linked vaccine antigen. The 4.2 Å structure of HIV-1 BG505 SOSIP soluble recombinant Env in complex with a CD4 binding site-specific broadly neutralizing antibody (bNAb) Fab fragment reveals how cross-linking affects key properties of the trimer. We observed density corresponding to highly specific glutaraldehyde (GLA) cross-links between gp120 monomers at the trimer apex and between gp120 and gp41 at the trimer interface that had strikingly little impact on overall trimer conformation, but critically enhanced trimer stability and improved Env antigenicity. Cross-links were also observed within gp120 at sites associated with the N241/N289 glycan hole that locally modified trimer antigenicity. In immunogenicity studies, the neutralizing antibody response to cross-linked trimers showed modest but significantly greater breadth against a global panel of difficult-to-neutralize Tier-2 heterologous viruses. Moreover, the specificity of autologous Tier-2 neutralization was modified away from the N241/N289 glycan hole, implying a novel specificity. Finally, we have investigated for the first time T helper cell responses to next-generation soluble trimers, and report on vaccine-relevant immunodominant responses to epitopes within BG505 that are modified by cross-linking. Elucidation of the structural correlates of a cross-linked viral glycoprotein will allow more rational use of this methodology for vaccine design, and reveals a strategy with promise for eliciting neutralizing antibodies needed for an effective HIV-1 vaccine.
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MESH Headings
- AIDS Vaccines/chemistry
- AIDS Vaccines/immunology
- Animals
- Antibodies, Neutralizing/immunology
- Antibody Specificity
- Antigen-Antibody Reactions/immunology
- Cross-Linking Reagents
- Cryoelectron Microscopy
- HIV Antibodies/immunology
- HIV Antigens/chemistry
- HIV Antigens/immunology
- HIV Antigens/ultrastructure
- HIV-1/chemistry
- HIV-1/immunology
- Host-Pathogen Interactions/immunology
- Humans
- Immunodominant Epitopes/chemistry
- Immunodominant Epitopes/immunology
- Mice
- Mice, Inbred BALB C
- Models, Molecular
- Protein Conformation
- Protein Stability
- Protein Structure, Quaternary
- Rabbits
- T-Lymphocytes, Helper-Inducer/immunology
- Vaccines, Synthetic/chemistry
- Vaccines, Synthetic/immunology
- env Gene Products, Human Immunodeficiency Virus/chemistry
- env Gene Products, Human Immunodeficiency Virus/immunology
- env Gene Products, Human Immunodeficiency Virus/ultrastructure
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Affiliation(s)
- Torben Schiffner
- The Sir William Dunn School of Pathology, The University of Oxford, Oxford, United Kingdom
| | - Jesper Pallesen
- Department of Integrative Structural and Computational Biology, IAVI Neutralizing Antibody Center, Collaboration for AIDS Vaccine Discovery and Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, California, United States of America
| | - Rebecca A Russell
- The Sir William Dunn School of Pathology, The University of Oxford, Oxford, United Kingdom
| | - Jonathan Dodd
- The Sir William Dunn School of Pathology, The University of Oxford, Oxford, United Kingdom
| | - Natalia de Val
- Center for Molecular Microscopy (CMM), National Cancer Institute (NCI), Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Celia C LaBranche
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, United States of America
| | - David Montefiori
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Georgia D Tomaras
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, United States of America
- Duke Human Vaccine Institute, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, United States of America
- Departments of Immunology and Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Xiaoying Shen
- Duke Human Vaccine Institute, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Scarlett L Harris
- The Sir William Dunn School of Pathology, The University of Oxford, Oxford, United Kingdom
| | - Amin E Moghaddam
- The Sir William Dunn School of Pathology, The University of Oxford, Oxford, United Kingdom
| | - Oleksandr Kalyuzhniy
- Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery (CHAVI-ID), The Scripps Research Institute, La Jolla, California, United States of America
- IAVI Neutralizing Antibody Center and the Collaboration for AIDS Vaccine Discovery (CAVD), The Scripps Research Institute, La Jolla, California, United States of America
| | - Rogier W Sanders
- Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Laura E McCoy
- Division of Infection and Immunity, University College London, London, United Kingdom
| | - John P Moore
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, IAVI Neutralizing Antibody Center, Collaboration for AIDS Vaccine Discovery and Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, California, United States of America
| | - Quentin J Sattentau
- The Sir William Dunn School of Pathology, The University of Oxford, Oxford, United Kingdom
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van Montfort T, Eggink D, Boot M, Tuen M, Hioe CE, Berkhout B, Sanders RW. HIV-1 N-glycan composition governs a balance between dendritic cell-mediated viral transmission and antigen presentation. THE JOURNAL OF IMMUNOLOGY 2011; 187:4676-85. [PMID: 21957147 DOI: 10.4049/jimmunol.1101876] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The natural function of dendritic cells (DCs) is to capture and degrade pathogens for Ag presentation. However, HIV-1 can evade viral degradation by DCs and hijack DCs for migration to susceptible CD4(+) T lymphocytes. It is unknown what factors decide whether a virus is degraded or transmitted to T cells. The interaction of DCs with HIV-1 involves C-type lectin receptors, such as DC-specific ICAM-3-grabbing nonintegrin, which bind to the envelope glycoprotein complex (Env), which is decorated heavily with N-linked glycans. We hypothesized that the saccharide composition of the Env N-glycans is involved in avoiding viral degradation and Ag presentation, as well as preserving infectious virus for the transmission to target cells. Therefore, we studied the fate of normally glycosylated virus versus oligomannose-enriched virus in DCs. Changing the heterogeneous N-linked glycan composition of Env to uniform oligomannose N-glycans increased the affinity of HIV-1 for DC-specific ICAM-3-grabbing nonintegrin and enhanced the capture of HIV-1 by immature DCs; however, it decreased the subsequent transmission to target cells. Oligomannose-enriched HIV-1 was directed more efficiently into the endocytic pathway, resulting in enhanced viral degradation and reduced virus transfer to target cells. Furthermore, Env containing exclusively oligomannose N-glycans was presented to Env-specific CD4(+) T cells more efficiently. Taken together, our results showed that the HIV-1 N-glycan composition plays a crucial role in the balance between DC-mediated Ag degradation and presentation and DC-mediated virus transmission to target cells. This finding may have implications for the early events in HIV-1 transmission and the induction of antiviral immune responses.
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Affiliation(s)
- Thijs van Montfort
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam, Academic Medical Center of the University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
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Li H, Xu CF, Blais S, Wan Q, Zhang HT, Landry SJ, Hioe CE. Proximal glycans outside of the epitopes regulate the presentation of HIV-1 envelope gp120 helper epitopes. THE JOURNAL OF IMMUNOLOGY 2009; 182:6369-78. [PMID: 19414790 DOI: 10.4049/jimmunol.0804287] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Glycosylation of HIV-1 envelope gp120 determines not only the proper structure, but also the immune responses against this Ag. Although glycans may be part of specific epitopes or shield other epitopes from T cells and Abs, this study provides evidence for a different immunomodulatory function of glycans associated with gp120 residues N230 and N448. These glycans are required for efficient MHC class II-restricted presentation of nearby CD4 T cell epitopes, even though they are not part of the epitopes. The glycans do not affect CD4 T cell recognition of more distant epitopes and are not essential for the proper folding and function of gp120. Data on CD4 T cell recognition of N448 mutants combined with proteolysis analyses and surface electrostatic potential calculation around residue N448 support the notion that N448 glycan near the epitope's C terminus renders the site to be surface accessible and allows its efficient processing. In contrast, the N230 glycan contributes to the nearby epitope presentation at a step other than the proteolytic processing of the epitope. Hence, N-glycans can determine CD4 T cell recognition of nearby gp120 epitopes by regulating the different steps in the MHC class II processing and presentation pathway after APCs acquire the intact gp120 Ag exogenously. Modifications of amino acids bearing glycans at the C termini of gp120 helper epitopes may prove to be a useful strategy for enhancing the immunogenicity of HIV-1 envelope gp120.
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Affiliation(s)
- Hualin Li
- Department of Veterans Affairs, New York Harbor Healthcare System, New York, NY, USA
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Li H, Chien PC, Tuen M, Visciano ML, Cohen S, Blais S, Xu CF, Zhang HT, Hioe CE. Identification of an N-linked glycosylation in the C4 region of HIV-1 envelope gp120 that is critical for recognition of neighboring CD4 T cell epitopes. THE JOURNAL OF IMMUNOLOGY 2008; 180:4011-21. [PMID: 18322210 DOI: 10.4049/jimmunol.180.6.4011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The heavy glycosylation of HIV-1 envelope gp120 shields this important Ag from recognition by neutralizing Abs and cytolytic CD8 T cells. However, very little work has been done to understand the influence of glycosylation on the generation of gp120 epitopes and their recognition by MHC class II-restricted CD4 T cells. In this study, three conserved glycans (linked to N406, N448, and N463) flanking the C4 region of gp120 that contains many known CD4 T cell epitopes were disrupted individually or in combination by asparagine-to-glutamine substitutions. The mutant proteins lacking the N448 glycan did not effectively stimulate CD4 T cells specific for the nearby C4 epitopes, although the same mutants were recognized well by CD4 T cells specific for epitopes located in the distant C1 and C2 regions. The loss of recognition was not due to amino acid substitutions introduced to the mutant proteins. Data from trypsin digestion and mass spectrometry analyses demonstrated that the N448 glycan removal impeded the proteolytic cleavage of the nearby C4 region, without affecting more distant sites. Importantly, this inhibitory effect was observed only in the digestion of the native nondenatured protein and not in that of the denatured protein. These data indicate that the loss of the N448 glycan induces structural changes in the C4 region of gp120 that make this specific region more resistant to proteolytic processing, thereby restricting the generation of CD4 T cell epitopes from this region. Hence, N-linked glycans are critical determinants that can profoundly influence CD4 T cell recognition of HIV-1 gp120.
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Affiliation(s)
- Hualin Li
- Department of Veterans Affairs New York Harbor Healthcare System, New York, NY 10010, USA
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Kaur G, Tuen M, Virland D, Cohen S, Mehra NK, Münz C, Abdelwahab S, Garzino-Demo A, Hioe CE. Antigen stimulation induces HIV envelope gp120-specific CD4(+) T cells to secrete CCR5 ligands and suppress HIV infection. Virology 2007; 369:214-25. [PMID: 17765942 PMCID: PMC2443714 DOI: 10.1016/j.virol.2007.07.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Revised: 07/19/2007] [Accepted: 07/31/2007] [Indexed: 02/08/2023]
Abstract
CD4(+) T cells are critical for effective immune responses against HIV, but they are also the main cell type targeted by the virus. To investigate the key factors that could protect these cells from infection, we evaluated the capacity of HIV gp120-specific human CD4(+) T cells to produce chemokines that inhibit HIV and determined their contribution in suppressing infection in the cells. Antigen stimulation of the CD4(+) T cells elicited production of high amounts of CCR5 chemokines MIP-1alpha (CCL3), MIP-1beta (CCL4), and RANTES (CCL5). Production of these CCR5 ligands was more readily and reproducibly detected than that of IFN-gamma or IL-2. Importantly, in association with secretion of the CCR5 ligands, antigen stimulation made these CD4(+) T cells more resistant to CCR5-tropic HIV-1. Conversely, in the absence of antigen stimulation, the cells were readily infected by the virus, and after infection, their capacity to produce MIP-1beta and IFN-gamma rapidly declined. Thus, vaccines that trigger HIV-specific CD4(+) T cells to elicit robust and rapid production of anti-viral chemokines would be advantageous. Such responses would protect virus-specific CD4(+) T cells from HIV infection and preserve their critical functions in mounting and maintaining long-lasting immunity against the virus.
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Affiliation(s)
- Gurvinder Kaur
- Department of Veterans Affairs New York Harbor Healthcare System and Department of Pathology, New York University School of Medicine, New York, New York, USA
- Department of Transplant Immunology and Immunogenetics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Michael Tuen
- Department of Veterans Affairs New York Harbor Healthcare System and Department of Pathology, New York University School of Medicine, New York, New York, USA
| | - Diana Virland
- Department of Veterans Affairs New York Harbor Healthcare System and Department of Pathology, New York University School of Medicine, New York, New York, USA
| | - Sandra Cohen
- Department of Veterans Affairs New York Harbor Healthcare System and Department of Pathology, New York University School of Medicine, New York, New York, USA
| | - Narinder K. Mehra
- Department of Transplant Immunology and Immunogenetics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Christian Münz
- Laboratory of Viral Immunobiology and Christopher H. Browne Center for Immunology and Immune Diseases, The Rockefeller University, New York, New York, USA
| | - Sayed Abdelwahab
- Laboratory of Virus-Host Interactions, Institute of Human Virology, University of Maryland Biotechnology Institute, Baltimore, USA
| | - Alfredo Garzino-Demo
- Laboratory of Virus-Host Interactions, Institute of Human Virology, University of Maryland Biotechnology Institute, Baltimore, USA
| | - Catarina E. Hioe
- Department of Veterans Affairs New York Harbor Healthcare System and Department of Pathology, New York University School of Medicine, New York, New York, USA
- Corresponding author. VA Medical Center, 423 E. 23 St. Room 18-124 North, New York, NY 10010, phone: 212-263-6769, fax: 212-951-6321,
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Tuen M, Visciano ML, Chien PC, Cohen S, Chen PD, Robinson J, He Y, Pinter A, Gorny MK, Hioe CE. Characterization of antibodies that inhibit HIV gp120 antigen processing and presentation. Eur J Immunol 2005; 35:2541-51. [PMID: 16106369 DOI: 10.1002/eji.200425859] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Antibodies to the CD4-binding site (CD4bs) of HIV-1 envelope gp120 have been shown to inhibit MHC class II presentation of this antigen, but the mechanism is not fully understood. To define the key determinants contributing to the inhibitory activity of these antibodies, a panel of anti-CD4bs monoclonal antibodies with different affinities was studied and compared to antibodies specific for the chemokine receptor-binding site or other gp120 regions. Anti-CD4bs antibodies that completely obstruct gp120 presentation exhibit three common properties: relatively high affinity for gp120, acid-stable interaction with gp120, and the capacity to slow the kinetics of gp120 proteolytic processing. None of these antibodies prevents gp120 internalization into APC. Notably, the broadly virus-neutralizing anti-CD4bs IgG1b12 does not block gp120 presentation as strongly, because although IgG1b12 has a relatively high affinity, it dissociates from gp120 more readily at acidic pH and only moderately retards gp120 proteolysis. Other anti-gp120 antibodies, regardless of their affinities, do not affect gp120 presentation. Hence, high-affinity anti-CD4bs antibodies that do not dissociate from gp120 at endolysosomal pH obstruct gp120 processing and prevent MHC class II presentation of this antigen. The presence of such antibodies could contribute to the dearth of anti-gp120 T helper responses in chronically HIV-1-infected patients.
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Affiliation(s)
- Michael Tuen
- Department of Pathology, New York University School of Medicine, and Veterans Affairs New York Harbor Healthcare System, New York, NY 10010, USA
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Chien PC, Cohen S, Tuen M, Arthos J, Chen PD, Patel S, Hioe CE. Human immunodeficiency virus type 1 evades T-helper responses by exploiting antibodies that suppress antigen processing. J Virol 2004; 78:7645-52. [PMID: 15220439 PMCID: PMC434093 DOI: 10.1128/jvi.78.14.7645-7652.2004] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
T-helper responses are important for controlling chronic viral infections, yet T-helper responses specific to human immunodeficiency virus type 1 (HIV-1), particularly to envelope glycoproteins, are lacking in the vast majority of HIV-infected individuals. It was previously shown that the presence of antibodies to the CD4-binding domain (CD4bd) of HIV-1 glycoprotein 120 (gp120) prevents T-helper responses to gp120, but their suppressive mechanisms were undefined (C. E. Hioe et al., J. Virol. 75:10950-10957, 2001). The present study demonstrates that gp120, when complexed to anti-CD4bd antibodies, becomes more resistant to proteolysis by lysosomal enzymes from antigen-presenting cells such that peptide epitopes are not released and presented efficiently by major histocompatibility complex class II molecules to gp120-specific CD4 T cells. Antibodies to other gp120 regions do not confer this effect. Thus, HIV may evade anti-viral T-helper responses by inducing and exploiting antibodies that conceal the virus envelope antigens from T cells.
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Affiliation(s)
- Peter C Chien
- Department of Pathology, New York University School of Medicine and Veterans Affairs, New York Harbor Healthcare System, New York, NY 10010, USA
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