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Doyon-Laliberté K, Aranguren M, Chagnon-Choquet J, Batraville LA, Dagher O, Richard J, Paniconi M, Routy JP, Tremblay C, Quintal MC, Brassard N, Kaufmann DE, Finzi A, Poudrier J, Roger M. Excess BAFF May Impact HIV-1-Specific Antibodies and May Promote Polyclonal Responses Including Those from First-Line Marginal Zone B-Cell Populations. Curr Issues Mol Biol 2023; 46:25-43. [PMID: 38275663 PMCID: PMC10814910 DOI: 10.3390/cimb46010003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 12/07/2023] [Accepted: 12/13/2023] [Indexed: 01/27/2024] Open
Abstract
We have previously shown that blood levels of B-cell Activating Factor (BAFF) rise relatively to disease progression status in the context of HIV-1 infection. Excess BAFF was concomitant with hyperglobulinemia and the deregulation of blood B-cell populations, notably with increased frequencies of a population sharing characteristics of transitional immature and marginal zone (MZ) B-cells, which we defined as marginal zone precursor-like" (MZp). In HIV-uninfected individuals, MZp present a B-cell regulatory (Breg) profile and function, which are lost in classic-progressors. Moreover, RNASeq analyses of blood MZp from classic-progressors depict a hyperactive state and signs of exhaustion, as well as an interferon signature similar to that observed in autoimmune disorders such as Systemic Lupus Erythematosus (SLE) and Sjögren Syndrome (SS), in which excess BAFF and deregulated MZ populations have also been documented. Based on the above, we hypothesize that excess BAFF may preclude the generation of HIV-1-specific IgG responses and drive polyclonal responses, including those from MZ populations, endowed with polyreactivity/autoreactivity. As such, we show that the quantity of HIV-1-specific IgG varies with disease progression status. In vitro, excess BAFF promotes polyclonal IgM and IgG responses, including those from MZp. RNASeq analyses reveal that blood MZp from classic-progressors are prone to Ig production and preferentially make usage of IGHV genes associated with some HIV broadly neutralizing antibodies (bNAbs), but also with autoantibodies, and whose impact in the battle against HIV-1 has yet to be determined.
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Affiliation(s)
- Kim Doyon-Laliberté
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (K.D.-L.); (M.A.); (J.C.-C.); (L.-A.B.); (O.D.); (J.R.); (C.T.); (N.B.); (D.E.K.); (A.F.)
- Département de Microbiologie, Infectiologie et Immunologie de l‘Université de Montréal, Montréal, QC H3T 1J4, Canada;
| | - Matheus Aranguren
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (K.D.-L.); (M.A.); (J.C.-C.); (L.-A.B.); (O.D.); (J.R.); (C.T.); (N.B.); (D.E.K.); (A.F.)
- Département de Microbiologie, Infectiologie et Immunologie de l‘Université de Montréal, Montréal, QC H3T 1J4, Canada;
| | - Josiane Chagnon-Choquet
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (K.D.-L.); (M.A.); (J.C.-C.); (L.-A.B.); (O.D.); (J.R.); (C.T.); (N.B.); (D.E.K.); (A.F.)
- Département de Microbiologie, Infectiologie et Immunologie de l‘Université de Montréal, Montréal, QC H3T 1J4, Canada;
| | - Laurie-Anne Batraville
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (K.D.-L.); (M.A.); (J.C.-C.); (L.-A.B.); (O.D.); (J.R.); (C.T.); (N.B.); (D.E.K.); (A.F.)
- Département de Microbiologie, Infectiologie et Immunologie de l‘Université de Montréal, Montréal, QC H3T 1J4, Canada;
| | - Olina Dagher
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (K.D.-L.); (M.A.); (J.C.-C.); (L.-A.B.); (O.D.); (J.R.); (C.T.); (N.B.); (D.E.K.); (A.F.)
- Département de Microbiologie, Infectiologie et Immunologie de l‘Université de Montréal, Montréal, QC H3T 1J4, Canada;
| | - Jonathan Richard
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (K.D.-L.); (M.A.); (J.C.-C.); (L.-A.B.); (O.D.); (J.R.); (C.T.); (N.B.); (D.E.K.); (A.F.)
- Département de Microbiologie, Infectiologie et Immunologie de l‘Université de Montréal, Montréal, QC H3T 1J4, Canada;
| | - Matteo Paniconi
- Département de Microbiologie, Infectiologie et Immunologie de l‘Université de Montréal, Montréal, QC H3T 1J4, Canada;
| | - Jean-Pierre Routy
- Department of Medicine, McGill University Health Centre, McGill University, Montréal, QC H4A 3J1, Canada;
| | - Cécile Tremblay
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (K.D.-L.); (M.A.); (J.C.-C.); (L.-A.B.); (O.D.); (J.R.); (C.T.); (N.B.); (D.E.K.); (A.F.)
- Département de Microbiologie, Infectiologie et Immunologie de l‘Université de Montréal, Montréal, QC H3T 1J4, Canada;
| | - Marie-Claude Quintal
- Centre Hospitalier Ste-Justine de l’Université de Montréal, Montréal, QC H3T 1C5, Canada;
| | - Nathalie Brassard
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (K.D.-L.); (M.A.); (J.C.-C.); (L.-A.B.); (O.D.); (J.R.); (C.T.); (N.B.); (D.E.K.); (A.F.)
| | - Daniel E. Kaufmann
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (K.D.-L.); (M.A.); (J.C.-C.); (L.-A.B.); (O.D.); (J.R.); (C.T.); (N.B.); (D.E.K.); (A.F.)
- Département de Médecine de l‘Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Andrés Finzi
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (K.D.-L.); (M.A.); (J.C.-C.); (L.-A.B.); (O.D.); (J.R.); (C.T.); (N.B.); (D.E.K.); (A.F.)
- Département de Microbiologie, Infectiologie et Immunologie de l‘Université de Montréal, Montréal, QC H3T 1J4, Canada;
| | - Johanne Poudrier
- Département de Microbiologie, Infectiologie et Immunologie de l‘Université de Montréal, Montréal, QC H3T 1J4, Canada;
| | - Michel Roger
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC H2X 0A9, Canada; (K.D.-L.); (M.A.); (J.C.-C.); (L.-A.B.); (O.D.); (J.R.); (C.T.); (N.B.); (D.E.K.); (A.F.)
- Département de Microbiologie, Infectiologie et Immunologie de l‘Université de Montréal, Montréal, QC H3T 1J4, Canada;
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Enhancement of CD4 Binding, Host Cell Entry, and Sensitivity to CD4bs Antibody Inhibition Conferred by a Natural but Rare Polymorphism in the HIV-1 Envelope. J Virol 2022; 96:e0185121. [PMID: 35862673 PMCID: PMC9327689 DOI: 10.1128/jvi.01851-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
A rare but natural polymorphism in the HIV-1 envelope (Env) glycoprotein, lysine at position 425 was selected as a mutation conferring resistance to maraviroc (MVC) in vitro. N425K has not been identified in HIV-infected individuals failing an MVC-based treatment. This study reports that the rare K425 polymorphism in an HIV-1 subtype A Env has increased affinity for CD4, resulting in faster host cell entry kinetics and the ability to scavenge for low cell surface expression of CD4 to mediate entry. Whereas the subtype A wild-type isolate-74 Env (N425) is inhibited by soluble (s) CD4, HIV-1 with K425 A74 Env shows enhanced infection and the ability to infect CCR5+ cells when pretreated with sCD4. Upon adding K425 or N425 HIV-1 to CD4+/CCR5+ cells along with RANTES/CCL3, only K425 HIV-1 was able to infect cells when CCR5 recycled/returned to the cell surface at 12 h post-treatment. These findings suggest that upon binding to CD4, K425 Env may maintain a stable State 2 "open" conformation capable of engaging CCR5 for entry. Only K425 was significantly more sensitivity than wild-type N425 A74 to inhibition by the CD4 binding site (bs) compound, BMS-806, the CD4bs antibody, VRC01 and N6, and the single-chain CD4i antibody, SCm9. K425 A74 was also capable of activating B cells expressing the VRC01 surface immunoglobulin. In summary, despite increased replicative fitness, we propose that K425 HIV-1 may be counterselected within infected individuals if K425 HIV-1 is rapidly eliminated by CD4bs-neutralizing antibodies. IMPORTANCE Typically, a natural amino acid polymorphism is found as the wild-type sequence in the HIV-1 population if it provides a selective advantage to the virus. The natural K425 polymorphism in HIV-1 Env results in higher host cell entry efficiency and greater replicative fitness by virtue of its high binding affinity to CD4. The studies presented herein suggest that the rare K425 HIV-1, compared to the common N425 HIV-1, may be more sensitive to inhibition by CD4bs-neutralizing antibodies (i.e., antibodies that bind to the CD4 binding pocket on the HIV-1 envelope glycoprotein). If CD4bs antibodies did emerge in an infected individual, the K425 HIV-1 may be hypersensitive to inhibition, and thus this K425 virus variant may be removed from the HIV-1 swarm despite its higher replication fitness. Studies are now underway to determine whether addition of the K425 polymorphism into the Envelope-based HIV-1 vaccines could enhance protective immunity.
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Schapiro HM, Khasnis MD, Ahn K, Karagiaridi A, Hayden S, Cilento ME, Root MJ. Regulation of epitope exposure in the gp41 membrane-proximal external region through interactions at the apex of HIV-1 Env. PLoS Pathog 2022; 18:e1010531. [PMID: 35584191 PMCID: PMC9154124 DOI: 10.1371/journal.ppat.1010531] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 05/31/2022] [Accepted: 04/18/2022] [Indexed: 11/19/2022] Open
Abstract
Glycoprotein Env of human immunodeficiency virus type 1 (HIV-1) mediates viral entry through membrane fusion. Composed of gp120 and gp41 subunits arranged as a trimer-of-heterodimers, Env adopts a metastable, highly dynamic conformation on the virion surface. This structural plasticity limits the temporospatial exposure of many highly conserved, neutralizing epitopes, contributing to the difficulty in developing effective HIV-1 vaccines. Here, we employed antibody neutralization of HIV-1 infectivity to investigate how inter- and intra-gp120 interactions mediated by variable loops V1/V2 and V3 at the Env apex regulate accessibility of the gp41 membrane-proximal external region (MPER) at the Env base. Swapping the V3 loop from EnvSF162 into the EnvHXB2 background shifted MPER exposure from the prefusogenic state to a functional intermediate conformation that was distinct from the prehairpin-intermediate state sensitive to gp41-targeted fusion inhibitors. The V3-loop swap had a profound impact on global protein dynamics, biasing the equilibrium to a closed conformation resistant to most anti-gp120 antibodies, stabilizing the protein to both cold- and soluble CD4-induced Env inactivation, and increasing the CD4 requirements for viral entry. Further dissection of the EnvHXB2 V3 loop revealed that residue 306 uniquely modulated epitope exposure and trimer stability. The R306S substitution substantially decreased sensitivity to antibodies targeting the gp41 MPER and, surprisingly, the gp120 V3-loop crown (residues 312–315), but had only modest effects on exposure of intervening gp120 epitopes. Furthermore, the point mutation reduced soluble CD4-induced inactivation, but had no impact on cold inactivation. The residue appeared to exert its effects by electrostatically modifying the strength of intra-subunit interactions between the V1/V2 and V3 loops. The distinct patterns of neutralization and stability pointed to a novel prefusogenic Env conformation along the receptor activation pathway and suggested that apical Env-regulation of gp41 MPER exposure can be decoupled from much of the dynamics of gp120 subunits. Surface glycoprotein Env is the main target for neutralizing antibodies elicited by HIV-1 vaccines. Env spontaneously fluctuates among different structures, limiting exposure of many attractive antibody-binding epitopes and, thereby, confounding vaccine development. To characterize these fluctuations, we examined how exposure of the MPER epitope found at the base of Env is regulated by interactions of the V3 loop located in the apex. Starting with an extremely flexible Env with a readily-exposed MPER, we identified two alterations that substantially restricted antibody access to the epitope. The first, a wholesale swap of V3 loops between HIV-1 strains, energetically stabilized Env in a closed structure that restricted access to antibodies throughout the protein. The second, a point mutation that altered V3-loop charge, specifically destabilized the MPER-exposed conformation but had minimal impact on antibody access to Env regions in between the apex and base. The results indicate that MPER exposure is not explicitly tied to the dynamics of Env regions between the apex and base and suggest a new structural fluctuation during Env activation.
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Affiliation(s)
- Hannah M. Schapiro
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Mukta D. Khasnis
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Koree Ahn
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Alexandra Karagiaridi
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Stephanie Hayden
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Maria E. Cilento
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Michael J. Root
- Department of Microbial Infection and Immunity, The Ohio State University College of Medicine, Columbus, Ohio, United States of America
- * E-mail:
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Friedrich N, Stiegeler E, Glögl M, Lemmin T, Hansen S, Kadelka C, Wu Y, Ernst P, Maliqi L, Foulkes C, Morin M, Eroglu M, Liechti T, Ivan B, Reinberg T, Schaefer JV, Karakus U, Ursprung S, Mann A, Rusert P, Kouyos RD, Robinson JA, Günthard HF, Plückthun A, Trkola A. Distinct conformations of the HIV-1 V3 loop crown are targetable for broad neutralization. Nat Commun 2021; 12:6705. [PMID: 34795280 PMCID: PMC8602657 DOI: 10.1038/s41467-021-27075-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 11/03/2021] [Indexed: 12/14/2022] Open
Abstract
The V3 loop of the HIV-1 envelope (Env) protein elicits a vigorous, but largely non-neutralizing antibody response directed to the V3-crown, whereas rare broadly neutralizing antibodies (bnAbs) target the V3-base. Challenging this view, we present V3-crown directed broadly neutralizing Designed Ankyrin Repeat Proteins (bnDs) matching the breadth of V3-base bnAbs. While most bnAbs target prefusion Env, V3-crown bnDs bind open Env conformations triggered by CD4 engagement. BnDs achieve breadth by focusing on highly conserved residues that are accessible in two distinct V3 conformations, one of which resembles CCR5-bound V3. We further show that these V3-crown conformations can, in principle, be attacked by antibodies. Supporting this conclusion, analysis of antibody binding activity in the Swiss 4.5 K HIV-1 cohort (n = 4,281) revealed a co-evolution of V3-crown reactivities and neutralization breadth. Our results indicate a role of V3-crown responses and its conformational preferences in bnAb development to be considered in preventive and therapeutic approaches.
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Affiliation(s)
- Nikolas Friedrich
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Emanuel Stiegeler
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,grid.424277.0Present Address: Roche Diagnostics GmbH, Nonnenwald 2, 82377 Penzberg, Deutschland
| | - Matthias Glögl
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Thomas Lemmin
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,grid.5801.c0000 0001 2156 2780Department of Computer Science, ETH Zurich, Zurich, Switzerland ,grid.29078.340000 0001 2203 2861Present Address: Euler Institute, Faculty of Biomedicine, Università della Svizzera italiana (USI), Lugano, Switzerland
| | - Simon Hansen
- grid.7400.30000 0004 1937 0650Department of Biochemistry, University of Zurich (UZH), Zurich, Switzerland ,Present Address: NGM Bio, 333 Oysterpoint Blvd, South San Francisco, CA 94080 USA
| | - Claus Kadelka
- grid.34421.300000 0004 1936 7312Department of Mathematics, Iowa State University, Ames, IA USA
| | - Yufan Wu
- grid.7400.30000 0004 1937 0650Department of Biochemistry, University of Zurich (UZH), Zurich, Switzerland ,Present Address: Innovent Biologics Inc, 168 Dongping Street, Suzhou Industrial Park, 215123 China
| | - Patrick Ernst
- grid.7400.30000 0004 1937 0650Department of Biochemistry, University of Zurich (UZH), Zurich, Switzerland ,grid.7400.30000 0004 1937 0650Present Address: Office Research and Teaching, Medical Faculty, University of Zurich, Zurich, Switzerland
| | - Liridona Maliqi
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Caio Foulkes
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Mylène Morin
- grid.7400.30000 0004 1937 0650Department of Chemistry, University of Zurich (UZH), Zurich, Switzerland ,Present Address: BeiGene Switzerland GmbH, Aeschengraben 27, 4051 Basel, Switzerland
| | - Mustafa Eroglu
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,Present Address: Janssen Vaccines AG, Rehhagstrasse 79, 3018 Bern, Switzerland
| | - Thomas Liechti
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,grid.419681.30000 0001 2164 9667Present Address: ImmunoTechnology Section, Vaccine Research Center, NIAID, NIH, Bethesda, MD USA
| | - Branislav Ivan
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,grid.410567.1Present Address: Laboratory Medicine, Division of Clinical Chemistry, University Hospital Basel, Basel, Switzerland
| | - Thomas Reinberg
- grid.7400.30000 0004 1937 0650Department of Biochemistry, University of Zurich (UZH), Zurich, Switzerland
| | - Jonas V. Schaefer
- grid.7400.30000 0004 1937 0650Department of Biochemistry, University of Zurich (UZH), Zurich, Switzerland ,grid.419481.10000 0001 1515 9979Present Address: Novartis Institutes for BioMedical Research, Chemical Biology & Therapeutics (CBT), Novartis Pharma AG, Virchow 16, 4056 Basel, Switzerland
| | - Umut Karakus
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Stephan Ursprung
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,grid.5335.00000000121885934Present Address: University of Cambridge School of Clinical Medicine, Department of Radiology, Cambridge, CB2 0QQ UK
| | - Axel Mann
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,Present Address: Roche Innovation Center Zurich, Roche Pharmaceutical Research and Early Development (pRED), Wagistrasse 10, 8952 Schlieren, Switzerland
| | - Peter Rusert
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Roger D. Kouyos
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,grid.412004.30000 0004 0478 9977Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich (USZ), Zurich, Switzerland
| | - John A. Robinson
- grid.7400.30000 0004 1937 0650Department of Chemistry, University of Zurich (UZH), Zurich, Switzerland
| | - Huldrych F. Günthard
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,grid.412004.30000 0004 0478 9977Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich (USZ), Zurich, Switzerland
| | - Andreas Plückthun
- grid.7400.30000 0004 1937 0650Department of Biochemistry, University of Zurich (UZH), Zurich, Switzerland
| | - Alexandra Trkola
- Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland.
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Prévost J, Medjahed H, Vézina D, Chen HC, Hahn BH, Smith AB, Finzi A. HIV-1 Envelope Glycoproteins Proteolytic Cleavage Protects Infected Cells from ADCC Mediated by Plasma from Infected Individuals. Viruses 2021; 13:2236. [PMID: 34835042 PMCID: PMC8625184 DOI: 10.3390/v13112236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/03/2021] [Accepted: 11/04/2021] [Indexed: 12/28/2022] Open
Abstract
The HIV-1 envelope glycoprotein (Env) is synthesized in the endoplasmic reticulum as a trimeric gp160 precursor, which requires proteolytic cleavage by a cellular furin protease to mediate virus-cell fusion. Env is conformationally flexible but controls its transition from the unbound "closed" conformation (State 1) to downstream CD4-bound conformations (States 2/3), which are required for fusion. In particular, HIV-1 has evolved several mechanisms that reduce the premature "opening" of Env which exposes highly conserved epitopes recognized by non-neutralizing antibodies (nnAbs) capable of mediating antibody-dependent cellular cytotoxicity (ADCC). Env cleavage decreases its conformational transitions favoring the adoption of the "closed" conformation. Here we altered the gp160 furin cleavage site to impair Env cleavage and to examine its impact on ADCC responses mediated by plasma from HIV-1-infected individuals. We found that infected primary CD4+ T cells expressing uncleaved, but not wildtype, Env are efficiently recognized by nnAbs and become highly susceptible to ADCC responses mediated by plasma from HIV-1-infected individuals. Thus, HIV-1 limits the exposure of uncleaved Env at the surface of HIV-1-infected cells at least in part to escape ADCC responses.
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Affiliation(s)
- Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada; (J.P.); (H.M.); (D.V.)
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H2X 0A9, Canada
| | - Halima Medjahed
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada; (J.P.); (H.M.); (D.V.)
| | - Dani Vézina
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada; (J.P.); (H.M.); (D.V.)
| | - Hung-Ching Chen
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA; (H.-C.C.); (A.B.S.III)
| | - Beatrice H. Hahn
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6076, USA;
| | - Amos B. Smith
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA; (H.-C.C.); (A.B.S.III)
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada; (J.P.); (H.M.); (D.V.)
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H2X 0A9, Canada
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6
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Tolbert WD, Nguyen DN, Tehrani ZR, Sajadi MM, Pazgier M. Near-Pan-neutralizing, Plasma Deconvoluted Antibody N49P6 Mimics Host Receptor CD4 in Its Quaternary Interactions with the HIV-1 Envelope Trimer. mBio 2021; 12:e0127421. [PMID: 34281393 PMCID: PMC8406290 DOI: 10.1128/mbio.01274-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/15/2021] [Indexed: 11/20/2022] Open
Abstract
The first step in HIV-1 entry is the attachment of the envelope (Env) trimer to target cell CD4. As such, the CD4-binding site (CD4bs) remains one of the few universally accessible sites for antibodies (Abs). We recently described a method of isolating Abs directly from the circulating plasma and described a panel of broadly neutralizing Abs (bnAbs) from an HIV-1 "elite neutralizer" referred to as patient N49 (N49 Ab lineage [M. M. Sajadi, A. Dashti, Z. R. Tehrani, W. D. Tolbert, et al., Cell 173:1783-1795.e14, 2018, https://doi.org/10.1016/j.cell.2018.03.061]). Here, we describe the molecular details of antigen recognition by N49P6, an Ab of the N49 lineage that recapitulates most of the neutralization breadth and potency of the donor's plasma IgG. Our studies done in the context of monomeric and trimeric antigens indicate that N49P6 combines many characteristics of known CD4bs-specific bnAbs with features that are unique to the N49 Ab lineage to achieve its remarkable neutralization breadth. These include the omission of the CD4 Phe43 cavity and dependence instead on interactions with highly conserved gp120 inner domain layer 3. Interestingly, when bound to BG505 SOSIP, N49P6 closely mimics the initial contact of host receptor CD4 to the adjacent promoter of the HIV-1 Env trimer to lock the trimer in the closed conformation. Altogether, N49P6 defines a new class of near-pan-neutralizing, plasma deconvoluted CD4bs Abs that we refer to as the N49P series. The details of the mechanisms of action of this new Ab class pave the way for the next generation of HIV-1 bnAbs that can be used as vaccine components of therapeutics. IMPORTANCE Binding to target cell CD4 is the first crucial step required for HIV-1 infection. Thus, the CD4-binding site (CD4bs) is one of the most accessible sites for antibodies (Abs). However, due to steric constraints, only a few Abs are capable of targeting this site. Here, we show that the exceptional neutralization breadth and potency of N49P6, a near-pan-neutralizing Ab targeting the CD4bs isolated from the plasma of an HIV-1 "elite neutralizer," patient N49, are due to its signature combination of more typical CD4bs Ab-binding characteristics with unique interactions with the highly conserved gp120 inner domain. In addition, we also present a structural analysis of N49P6 in complex with the BG505 SOSIP trimer to show that N49P6 exhibits remarkable breadth in part by mimicking CD4's quaternary interaction with the neighboring gp120 protomer. In its mode of antigen interaction, N49P6 is unique and represents a new class of CD4bs-specific bnAbs.
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Affiliation(s)
- William D. Tolbert
- Infectious Disease Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Dung N. Nguyen
- Infectious Disease Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Zahra Rikhtegaran Tehrani
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Division of Clinical Care and Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Mohammad M. Sajadi
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Division of Clinical Care and Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, Baltimore VA Medical Center, Baltimore, Maryland, USA
| | - Marzena Pazgier
- Infectious Disease Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
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7
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Li H, Wang S, Lee FH, Roark RS, Murphy AI, Smith J, Zhao C, Rando J, Chohan N, Ding Y, Kim E, Lindemuth E, Bar KJ, Pandrea I, Apetrei C, Keele BF, Lifson JD, Lewis MG, Denny TN, Haynes BF, Hahn BH, Shaw GM. New SHIVs and Improved Design Strategy for Modeling HIV-1 Transmission, Immunopathogenesis, Prevention and Cure. J Virol 2021; 95:JVI.00071-21. [PMID: 33658341 PMCID: PMC8139694 DOI: 10.1128/jvi.00071-21] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 02/24/2021] [Indexed: 12/14/2022] Open
Abstract
Previously, we showed that substitution of HIV-1 Env residue 375-Ser by bulky aromatic residues enhances binding to rhesus CD4 and enables primary HIV-1 Envs to support efficient replication as simian-human immunodeficiency virus (SHIV) chimeras in rhesus macaques (RMs). Here, we test this design strategy more broadly by constructing SHIVs containing ten primary Envs corresponding to HIV-1 subtypes A, B, C, AE and AG. All ten SHIVs bearing wildtype Env375 residues replicated efficiently in human CD4+ T cells, but only one replicated efficiently in primary rhesus cells. This was a subtype AE SHIV that naturally contained His at Env375. Replacement of wildtype Env375 residues by Trp, Tyr, Phe or His in the other nine SHIVs led to efficient replication in rhesus CD4+ T cells in vitro and in vivo Nine SHIVs containing optimized Env375 alleles were grown large-scale in primary rhesus CD4+ T cells to serve as challenge stocks in preclinical prevention trials. These virus stocks were genetically homogeneous, native-like in Env antigenicity and tier-2 neutralization sensitivity, and transmissible by rectal, vaginal, penile, oral or intravenous routes. To facilitate future SHIV constructions, we engineered a simplified second-generation design scheme and validated it in RMs. Overall, our findings demonstrate that SHIVs bearing primary Envs with bulky aromatic substitutions at Env375 consistently replicate in RMs, recapitulating many features of HIV-1 infection in humans. Such SHIVs are efficiently transmitted by mucosal routes common to HIV-1 infection and can be used to test vaccine efficacy in preclinical monkey trials.ImportanceSHIV infection of Indian rhesus macaques is an important animal model for studying HIV-1 transmission, prevention, immunopathogenesis and cure. Such research is timely, given recent progress with active and passive immunization and novel approaches to HIV-1 cure. Given the multifaceted roles of HIV-1 Env in cell tropism and virus entry, and as a target for neutralizing and non-neutralizing antibodies, Envs selected for SHIV construction are of paramount importance. Until recently, it has been impossible to strategically design SHIVs bearing clinically relevant Envs that replicate consistently in monkeys. This changed with the discovery that bulky aromatic substitutions at residue Env375 confer enhanced affinity to rhesus CD4. Here, we show that 10 new SHIVs bearing primary HIV-1 Envs with residue 375 substitutions replicated efficiently in RMs and could be transmitted efficiently across rectal, vaginal, penile and oral mucosa. These findings suggest an expanded role for SHIVs as a model of HIV-1 infection.
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Affiliation(s)
- Hui Li
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Shuyi Wang
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Fang-Hua Lee
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ryan S Roark
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Alex I Murphy
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jessica Smith
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Chengyan Zhao
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Juliette Rando
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Neha Chohan
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yu Ding
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Eunlim Kim
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Emily Lindemuth
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Katharine J Bar
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ivona Pandrea
- Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Cristian Apetrei
- Division of Infectious Diseases, Department of Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Brandon F Keele
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Jeffrey D Lifson
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | | | - Thomas N Denny
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Barton F Haynes
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Beatrice H Hahn
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - George M Shaw
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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8
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Ding S, Laumaea A, Benlarbi M, Beaudoin-Bussières G, Gasser R, Medjahed H, Pancera M, Stamatatos L, McGuire AT, Bazin R, Finzi A. Antibody Binding to SARS-CoV-2 S Glycoprotein Correlates with but Does Not Predict Neutralization. Viruses 2020; 12:E1214. [PMID: 33114742 PMCID: PMC7692607 DOI: 10.3390/v12111214] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 10/22/2020] [Indexed: 01/02/2023] Open
Abstract
Convalescent plasma from SARS-CoV-2 infected individuals and monoclonal antibodies were shown to potently neutralize viral and pseudoviral particles carrying the S glycoprotein. However, a non-negligent proportion of plasma samples from infected individuals, as well as S-specific monoclonal antibodies, were reported to be non-neutralizing despite efficient interaction with the S glycoprotein in different biochemical assays using soluble recombinant forms of S or when expressed at the cell surface. How neutralization relates to the binding of S glycoprotein in the context of viral particles remains to be established. Here, we developed a pseudovirus capture assay (VCA) to measure the capacity of plasma samples or antibodies immobilized on ELISA plates to bind to membrane-bound S glycoproteins from SARS-CoV-2 expressed at the surface of lentiviral particles. By performing VCA, ELISA, and neutralization assays, we observed a strong correlation between these parameters. However, while we found that plasma samples unable to capture viral particles did not neutralize, capture did not guarantee neutralization, indicating that the capacity of antibodies to bind to the S glycoprotein at the surface of pseudoviral particles is required but not sufficient to mediate neutralization. Altogether, our results highlight the importance of better understanding the inactivation of S by plasma and neutralizing antibodies.
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Affiliation(s)
- Shilei Ding
- Centre de Recherche du CHUM, Montréal, QC H2X 0A9, Canada; (S.D.); (A.L.); (M.B.); (G.B.-B.); (R.G.); (H.M.)
| | - Annemarie Laumaea
- Centre de Recherche du CHUM, Montréal, QC H2X 0A9, Canada; (S.D.); (A.L.); (M.B.); (G.B.-B.); (R.G.); (H.M.)
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H2X 0A9, Canada
| | - Mehdi Benlarbi
- Centre de Recherche du CHUM, Montréal, QC H2X 0A9, Canada; (S.D.); (A.L.); (M.B.); (G.B.-B.); (R.G.); (H.M.)
| | - Guillaume Beaudoin-Bussières
- Centre de Recherche du CHUM, Montréal, QC H2X 0A9, Canada; (S.D.); (A.L.); (M.B.); (G.B.-B.); (R.G.); (H.M.)
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H2X 0A9, Canada
| | - Romain Gasser
- Centre de Recherche du CHUM, Montréal, QC H2X 0A9, Canada; (S.D.); (A.L.); (M.B.); (G.B.-B.); (R.G.); (H.M.)
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H2X 0A9, Canada
| | - Halima Medjahed
- Centre de Recherche du CHUM, Montréal, QC H2X 0A9, Canada; (S.D.); (A.L.); (M.B.); (G.B.-B.); (R.G.); (H.M.)
| | - Marie Pancera
- Fred Hutchinson Cancer Research Center, Vaccines and Infectious Diseases Division, Seattle, 98109 WA, USA; (M.P.); (L.S.); (A.T.M.)
- Vaccine Research Center, National Institutes of Allergy and Infectious Diseases, National Institute of Health, Bethesda, 20892 MD, USA
| | - Leonidas Stamatatos
- Fred Hutchinson Cancer Research Center, Vaccines and Infectious Diseases Division, Seattle, 98109 WA, USA; (M.P.); (L.S.); (A.T.M.)
- Department of Global Health, University of Washington, Seattle, 98195 WA, USA
| | - Andrew T. McGuire
- Fred Hutchinson Cancer Research Center, Vaccines and Infectious Diseases Division, Seattle, 98109 WA, USA; (M.P.); (L.S.); (A.T.M.)
- Department of Global Health, University of Washington, Seattle, 98195 WA, USA
| | - Renée Bazin
- Héma-Québec, Affaires Médicales et Innovation, Québec, QC G1V 5C3, Canada;
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montréal, QC H2X 0A9, Canada; (S.D.); (A.L.); (M.B.); (G.B.-B.); (R.G.); (H.M.)
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H2X 0A9, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, QC H3A 2B4, Canada
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9
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Kant S, Zhang N, Barbé A, Routy JP, Tremblay C, Thomas R, Szabo J, Côté P, Trottier B, LeBlanc R, Rouleau D, Harris M, Dupuy FP, Bernard NF. Polyfunctional Fc Dependent Activity of Antibodies to Native Trimeric Envelope in HIV Elite Controllers. Front Immunol 2020; 11:583820. [PMID: 33101312 PMCID: PMC7555699 DOI: 10.3389/fimmu.2020.583820] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/10/2020] [Indexed: 12/17/2022] Open
Abstract
Antibody dependent (AD) functions such as AD cellular cytotoxicity (ADCC) were associated with lower viral load (VL) in untreated HIV progressors and protection from HIV infection in the modestly protective RV144 HIV vaccine trial. Target cells used to measure ADCC, AD complement deposition (ADCD), and AD cellular trogocytosis (ADCT) have been either HIV envelope (Env) gp120-coated CEM.NKr.CCR5 cells or HIV infected cell cultures. In HIV infected cell cultures, uninfected bystander cells take up gp120 shed from infected cells. Both gp120-coated and gp120+ bystander cells expose CD4 induced (CD4i) epitopes, which are normally hidden in native trimeric Env expressed by genuinely HIV infected cells since Nef and Vpu downmodulate cell surface CD4. Antibody dependent assays using either of these target cells probe for CD4i Abs that are abundant in HIV+ plasma but that do not recognize HIV-infected cells. Here, we examined ADCC, ADCD, and ADCT functions using a target cell line, sorted HIV-infected cell line cells, whose HIV infection frequency nears 100% and that expresses HIV Env in a native trimeric closed conformation. Using sorted HIV-infected cells (siCEM) as targets, we probed the binding and AD functions of anti-gp120/Env Abs in plasma from HIV-infected untreated progressor (UTP, n = 18) and treated (TP, n = 24) subjects, compared to that in Elite controllers (EC, n = 37) and Viral Controllers (VC, n = 16), which are rare subsets of HIV-infected individuals who maintain undetectable or low VL, respectively, without treatment. Gp120-coated beads were used to measure AD cellular phagocytosis. Equivalent concentrations of input IgG in plasma from UTPs, ECs, and VCs supported higher levels of all AD functions tested than plasma from TPs. When AD activities were normalized to the concentration of anti-gp120/Env-specific Abs, between-group differences largely disappeared. This finding suggests that the anti-gp120/Env Abs concentrations and not their potency determined AD functional levels in these assays. Elite controllers did differ from the other groups by having AD functions that were highly polyfunctional and highly correlated with each other. PCR measurement of HIV reservoir size showed that ADCC activity was higher in ECs and VCs with a reservoir size below the limit of detection compared to those having a measurable HIV reservoir size.
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Affiliation(s)
- Sanket Kant
- Research Institute of the McGill University Health Centre Montreal, Montreal, QC, Canada.,Division of Experimental Medicine, McGill University, Montreal, QC, Canada.,Infectious Diseases, Immunology and Global Health Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Ningyu Zhang
- Research Institute of the McGill University Health Centre Montreal, Montreal, QC, Canada.,Infectious Diseases, Immunology and Global Health Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Alexandre Barbé
- Research Institute of the McGill University Health Centre Montreal, Montreal, QC, Canada.,Faculté de Médecine de l'Université de Lille Henri Warembourg, Lille, France.,Ophthalmology Department, Lille University Hospital, Lille, France
| | - Jean-Pierre Routy
- Research Institute of the McGill University Health Centre Montreal, Montreal, QC, Canada.,Infectious Diseases, Immunology and Global Health Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada.,Division of Hematology, McGill University Health Centre, Montreal, QC, Canada.,Chronic Viral Illness Service, McGill University Health Centre, Montreal, QC, Canada
| | - Cécile Tremblay
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada.,Départment de Microbiologie Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
| | | | - Jason Szabo
- Infectious Diseases, Immunology and Global Health Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada.,Chronic Viral Illness Service, McGill University Health Centre, Montreal, QC, Canada.,Clinique Médicale l'Actuel, Montreal, QC, Canada
| | - Pierre Côté
- Clinique de Médecine Urbaine du Quartier Latin, Montreal, QC, Canada
| | - Benoit Trottier
- Clinique de Médecine Urbaine du Quartier Latin, Montreal, QC, Canada
| | | | - Danielle Rouleau
- Départment de Microbiologie Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
| | - Marianne Harris
- British Columbia Center for Excellence in HIV/AIDS, Vancouver, BC, Canada
| | - Franck P Dupuy
- Research Institute of the McGill University Health Centre Montreal, Montreal, QC, Canada.,Infectious Diseases, Immunology and Global Health Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Nicole F Bernard
- Research Institute of the McGill University Health Centre Montreal, Montreal, QC, Canada.,Division of Experimental Medicine, McGill University, Montreal, QC, Canada.,Infectious Diseases, Immunology and Global Health Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada.,Chronic Viral Illness Service, McGill University Health Centre, Montreal, QC, Canada.,Division of Clinical Immunology, McGill University Health Centre, Montreal, QC, Canada
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10
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Antibody binding to SARS-CoV-2 S glycoprotein correlates with, but does not predict neutralization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020. [PMID: 32935094 DOI: 10.1101/2020.09.08.287482] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Convalescent plasma from SARS-CoV-2 infected individuals and monoclonal antibodies were shown to potently neutralize viral and pseudoviral particles carrying the S glycoprotein. However, a non-negligent proportion of plasma samples from infected individuals as well as S-specific monoclonal antibodies were reported to be non-neutralizing despite efficient interaction with the S glycoprotein in different biochemical assays using soluble recombinant forms of S or when expressed at the cell surface. How neutralization relates to binding of S glycoprotein in the context of viral particles remains to be established. Here we developed a pseudovirus capture assay (VCA) to measure the capacity of plasma samples or antibodies immobilized on ELISA plates to bind to membrane-bound S glycoproteins from SARS-CoV-2 expressed at the surface of lentiviral particles. By performing VCA and neutralization assays we observed a strong correlation between these two parameters. However, while we found that plasma samples unable to capture viral particles did not neutralize, capture did not guarantee neutralization, indicating that the capacity of antibodies to bind to the S glycoprotein at the surface of viral particles is required but not sufficient to mediate neutralization. Altogether, our results highlights the importance of better understanding the inactivation of S by plasma and neutralizing antibodies.
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11
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Prévost J, Tolbert WD, Medjahed H, Sherburn RT, Madani N, Zoubchenok D, Gendron-Lepage G, Gaffney AE, Grenier MC, Kirk S, Vergara N, Han C, Mann BT, Chénine AL, Ahmed A, Chaiken I, Kirchhoff F, Hahn BH, Haim H, Abrams CF, Smith AB, Sodroski J, Pazgier M, Finzi A. The HIV-1 Env gp120 Inner Domain Shapes the Phe43 Cavity and the CD4 Binding Site. mBio 2020; 11:e00280-20. [PMID: 32457241 PMCID: PMC7251204 DOI: 10.1128/mbio.00280-20] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 04/24/2020] [Indexed: 12/22/2022] Open
Abstract
The HIV-1 envelope glycoproteins (Env) undergo conformational changes upon interaction of the gp120 exterior glycoprotein with the CD4 receptor. The gp120 inner domain topological layers facilitate the transition of Env to the CD4-bound conformation. CD4 engages gp120 by introducing its phenylalanine 43 (Phe43) in a cavity ("the Phe43 cavity") located at the interface between the inner and outer gp120 domains. Small CD4-mimetic compounds (CD4mc) can bind within the Phe43 cavity and trigger conformational changes similar to those induced by CD4. Crystal structures of CD4mc in complex with a modified CRF01_AE gp120 core revealed the importance of these gp120 inner domain layers in stabilizing the Phe43 cavity and shaping the CD4 binding site. Our studies reveal a complex interplay between the gp120 inner domain and the Phe43 cavity and generate useful information for the development of more-potent CD4mc.IMPORTANCE The Phe43 cavity of HIV-1 envelope glycoproteins (Env) is an attractive druggable target. New promising compounds, including small CD4 mimetics (CD4mc), were shown to insert deeply into this cavity. Here, we identify a new network of residues that helps to shape this highly conserved CD4 binding pocket and characterize the structural determinants responsible for Env sensitivity to small CD4 mimetics.
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Affiliation(s)
- Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - William D Tolbert
- Infectious Diseases Division, Department of Medicine of Uniformed Services, University of the Health Sciences, Bethesda, Maryland, USA
| | | | - Rebekah T Sherburn
- Infectious Diseases Division, Department of Medicine of Uniformed Services, University of the Health Sciences, Bethesda, Maryland, USA
| | - Navid Madani
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Daria Zoubchenok
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | | | - Althea E Gaffney
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Melissa C Grenier
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sharon Kirk
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Natasha Vergara
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Changze Han
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Brendan T Mann
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
- Henry M. Jackson Foundation for the Advancement of the Military Medicine, Bethesda, Maryland, USA
| | - Agnès L Chénine
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
- Henry M. Jackson Foundation for the Advancement of the Military Medicine, Bethesda, Maryland, USA
| | - Adel Ahmed
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Irwin Chaiken
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Beatrice H Hahn
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hillel Haim
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Cameron F Abrams
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Amos B Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Marzena Pazgier
- Infectious Diseases Division, Department of Medicine of Uniformed Services, University of the Health Sciences, Bethesda, Maryland, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
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12
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Ding S, Grenier MC, Tolbert WD, Vézina D, Sherburn R, Richard J, Prévost J, Chapleau JP, Gendron-Lepage G, Medjahed H, Abrams C, Sodroski J, Pazgier M, Smith AB, Finzi A. A New Family of Small-Molecule CD4-Mimetic Compounds Contacts Highly Conserved Aspartic Acid 368 of HIV-1 gp120 and Mediates Antibody-Dependent Cellular Cytotoxicity. J Virol 2019; 93:e01325-19. [PMID: 31554684 PMCID: PMC6880173 DOI: 10.1128/jvi.01325-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 09/18/2019] [Indexed: 12/20/2022] Open
Abstract
The HIV-1 envelope glycoprotein (Env) trimer mediates virus entry into cells. The "closed" conformation of Env is resistant to nonneutralizing antibodies (nnAbs). These antibodies mostly recognize occluded epitopes that can be exposed upon binding of CD4 or small-molecule CD4 mimetics (CD4mc). Here, we describe a new family of small molecules that expose Env to nnAbs and sensitize infected cells to antibody-dependent cellular cytotoxicity (ADCC). These compounds have a limited capacity to inhibit virus infection directly but are able to sensitize viral particles to neutralization by otherwise nonneutralizing antibodies. Structural analysis shows that some analogs of this family of CD4mc engage the gp120 Phe43 cavity by contacting the highly conserved D368 residue, making them attractive scaffolds for drug development.IMPORTANCE HIV-1 has evolved multiple strategies to avoid humoral responses. One efficient mechanism is to keep its envelope glycoprotein (Env) in its "closed" conformation. Here, we report on a new family of small molecules that are able to "open up" Env, thus exposing vulnerable epitopes. This new family of molecules binds in the Phe43 cavity and contacts the highly conserved D368 residue. The structural and biological attributes of molecules of this family make them good candidates for drug development.
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Affiliation(s)
- Shilei Ding
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Melissa C Grenier
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - William D Tolbert
- Infectious Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Dani Vézina
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Rebekah Sherburn
- Infectious Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Jonathan Richard
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Jean-Philippe Chapleau
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | | | | | - Cameron Abrams
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania, USA
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Marzena Pazgier
- Infectious Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Amos B Smith
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
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13
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Ding S, Gasser R, Gendron-Lepage G, Medjahed H, Tolbert WD, Sodroski J, Pazgier M, Finzi A. CD4 Incorporation into HIV-1 Viral Particles Exposes Envelope Epitopes Recognized by CD4-Induced Antibodies. J Virol 2019; 93:e01403-19. [PMID: 31484748 PMCID: PMC6819941 DOI: 10.1128/jvi.01403-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 08/29/2019] [Indexed: 12/23/2022] Open
Abstract
CD4 downregulation on infected cells is a highly conserved function of primate lentiviruses. It has been shown to positively impact viral replication by a variety of mechanisms, including enhanced viral release and infectivity, decrease of cell reinfection, and protection from antibody-dependent cellular cytotoxicity (ADCC), which is often mediated by antibodies that require CD4 to change envelope (Env) conformation. Here, we report that incorporation of CD4 into HIV-1 viral particles affects Env conformation resulting in the exposure of occluded epitopes recognized by CD4-induced antibodies. This translates into enhanced neutralization susceptibility by these otherwise nonneutralizing antibodies but is prevented by the HIV-1 Nef accessory protein. Altogether, these findings suggest that another functional consequence of Nef-mediated CD4 downregulation is the protection of viral particles from neutralization by commonly elicited CD4-induced antibodies.IMPORTANCE It has been well established that Env-CD4 complexes expose epitopes recognized by commonly elicited CD4-induced antibodies at the surface of HIV-1-infected cells, rendering them vulnerable to ADCC responses. Here, we show that CD4 incorporation has a profound impact on Env conformation at the surface of viral particles. Incorporated CD4 exposes CD4-induced epitopes on Env, rendering HIV-1 susceptible to neutralization by otherwise nonneutralizing antibodies.
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Affiliation(s)
- Shilei Ding
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Romain Gasser
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | | | | | - William D Tolbert
- Infectious Diseases Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Marzena Pazgier
- Infectious Diseases Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
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14
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Mutations That Increase the Stability of the Postfusion gp41 Conformation of the HIV-1 Envelope Glycoprotein Are Selected by both an X4 and R5 HIV-1 Virus To Escape Fusion Inhibitors Corresponding to Heptad Repeat 1 of gp41, but the gp120 Adaptive Mutations Differ between the Two Viruses. J Virol 2019; 93:JVI.00142-19. [PMID: 30894471 DOI: 10.1128/jvi.00142-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Accepted: 03/15/2019] [Indexed: 02/06/2023] Open
Abstract
Binding of the gp120 surface subunit of the envelope glycoprotein (Env) of HIV-1 to CD4 and chemokine receptors on target cells triggers refolding of the gp41 transmembrane subunit into a six-helix bundle (6HB) that promotes fusion between virus and host cell membranes. To elucidate details of Env entry and potential differences between viruses that use CXCR4 (X4) or CCR5 (R5) coreceptors, we generated viruses that are resistant to peptide fusion inhibitors corresponding to the first heptad repeat region (HR1) of gp41 that target fusion-intermediate conformations of Env. Previously we reported that an R5 virus selected two resistance pathways, each defined by an early gp41 resistance mutation in either HR1 or the second heptad repeat (HR2), to escape inhibition by an HR1 peptide, but preferentially selected the HR1 pathway to escape inhibition by a trimer-stabilized HR1 peptide. Here, we report that an X4 virus selected the same HR1 and HR2 resistance pathways as the R5 virus to escape inhibition by the HR1 peptide. However, in contrast to the R5 virus, the X4 virus selected a unique mutation in HR2 to escape inhibition by the trimer-stabilized peptide. Significantly, both of these X4 and R5 viruses acquired gp41 resistance mutations that improved the thermostability of the six-helix bundle, but they selected different gp120 adaptive mutations. These findings show that these X4 and R5 viruses use a similar resistance mechanism to escape from HR1 peptide inhibition but different gp120-gp41 interactions to regulate Env conformational changes.IMPORTANCE HIV-1 fuses with cells when the gp41 subunit of Env refolds into a 6HB after binding to cellular receptors. Peptides corresponding to HR1 or HR2 interrupt gp41 refolding and inhibit HIV infection. Previously, we found that a CCR5 coreceptor-tropic HIV-1 acquired a key HR1 or HR2 resistance mutation to escape HR1 peptide inhibitors but only the key HR1 mutation to escape a trimer-stabilized HR1 peptide inhibitor. Here, we report that a CXCR4 coreceptor-tropic HIV-1 selected the same key HR1 or HR2 mutations to escape inhibition by the HR1 peptide but different combinations of HR1 and HR2 mutations to escape the trimer-stabilized HR1 peptide. All gp41 mutations enhance 6HB stability to outcompete inhibitors, but gp120 adaptive mutations differed between these R5 and X4 viruses, providing new insights into gp120-gp41 functional interactions affecting Env refolding during HIV entry.
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15
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SOSIP Changes Affect Human Immunodeficiency Virus Type 1 Envelope Glycoprotein Conformation and CD4 Engagement. J Virol 2018; 92:JVI.01080-18. [PMID: 30021898 DOI: 10.1128/jvi.01080-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 07/13/2018] [Indexed: 01/31/2023] Open
Abstract
The entry of human immunodeficiency virus into host cells is mediated by the envelope glycoprotein (Env) trimeric spike, which consists of three exterior gp120 subunits and three transmembrane gp41 subunits. The trimeric Env undergoes extensive conformational rearrangement upon interaction with the CD4 receptor, transitioning from the unliganded, "closed" State 1 to more-open downstream State 2 and State 3 conformations. Changes in "restraining" amino acid residues, such as leucine 193 and isoleucine 423, destabilize State 1 Env, which then assumes entry-competent, downstream conformations. The introduction of an artificial disulfide bond linking the gp120 and gp41 subunits (SOS) in combination with the I559P (IP) change has allowed structural characterization of soluble gp140 (sgp140) trimers. The conformation of these SOSIP-stabilized sgp140 trimers has been suggested to represent the closed native State 1 conformation. Here we compare the impact on the membrane Env conformation of the SOSIP changes with that of the well-characterized changes (L193R and I423A) that shift Env to downstream States 2 and 3. The results presented here suggest that the SOSIP changes stabilize Env in a conformation that differs from State 1 but also from the downstream Env conformations stabilized by L193R or I423A.IMPORTANCE The human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) trimer is triggered by receptor binding to mediate the entry of the virus into cells. Most structural studies of Env trimers have utilized truncated soluble gp140 Envs stabilized with the I559P and SOS changes. Here we present evidence indicating that these stabilizing changes have a profound impact on the conformation of Env, moving Env away from the native pretriggered Env conformation. Our studies underscore the need to acquire structural information on the pretriggered Env conformation, which is recognized by most broadly reactive neutralizing antibodies.
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16
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Human IgM monoclonal antibodies block HIV-transmission to immune cells in cervico-vaginal tissues and across polarized epithelial cells in vitro. Sci Rep 2018; 8:10180. [PMID: 29977063 PMCID: PMC6033918 DOI: 10.1038/s41598-018-28242-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 06/19/2018] [Indexed: 12/20/2022] Open
Abstract
The importance of natural IgM antibodies in protection against infections is still emerging and these antibodies have a potential role in the maintenance of homeostasis through clearance of apoptotic bodies, complement-dependent mechanisms, inflammation and exclusion of misfolded proteins. Natural IgM act as a first line of defence against unknown hazardous factors and are present in most vertebrates. We investigated the functional capacity of anti-HIV-1 IgM monoclonal antibodies, from a combinatorial Fab library derived from healthy individuals, and evaluated their protective role in inhibiting HIV-1 in vitro when passing across the human mucosal epithelial barrier. Primary HIV-1 isolates were efficiently transmitted over the tight polarized epithelial cells when added to their apical surface. Efficient inhibition of HIV-1 transmission was achieved when anti-HIV-1 IgM monoclonal antibodies were added to the basolateral side of the cells. Two of these human IgM MoAbs had the ability to neutralize HIV and reduced infection of dendritic cells in primary cervico-vaginal tissue biopsies in vitro. This indicates a potential role of natural IgM antibodies in the reduction of HIV-1 transmission in mucosal tissues and improve our understanding of how natural IgM antibodies against a neutralizing epitope could interfere with viral transmission.
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Richard J, Prévost J, Alsahafi N, Ding S, Finzi A. Impact of HIV-1 Envelope Conformation on ADCC Responses. Trends Microbiol 2017; 26:253-265. [PMID: 29162391 DOI: 10.1016/j.tim.2017.10.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 10/17/2017] [Accepted: 10/26/2017] [Indexed: 01/30/2023]
Abstract
HIV-1 envelope glycoproteins (Env) represent the only virus-specific antigen exposed at the surface of infected cells. In its unliganded form, Env from primary viruses samples a 'closed' conformation (State 1), which is preferentially recognized by broadly neutralizing antibodies (bNAbs). CD4 engagement drives Env into an intermediate 'partially open' (State 2) and then into the 'open' CD4-bound conformation (State 3). Emerging evidence suggests a link between Env conformation and Ab-dependent cellular cytotoxicity (ADCC). HIV-1-infected cells exposing Env in the CD4-bound conformation are susceptible to ADCC mediated by CD4-induced Abs and HIV+sera. Cells exposing State 1 Env are susceptible to ADCC mediated by bNAbs. Here, we discuss how Env conformation affects ADCC responses and in vitro measurements.
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Affiliation(s)
- Jonathan Richard
- Centre de Recherche du CHUM, Montreal, QC, H2X 0A9, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, QC, H2X 0A9, Canada; These authors contributed equally
| | - Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, QC, H2X 0A9, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, QC, H2X 0A9, Canada; These authors contributed equally
| | - Nirmin Alsahafi
- Centre de Recherche du CHUM, Montreal, QC, H2X 0A9, Canada; Department of Microbiology and Immunology, McGill University, Montreal, QC, H3A 2B4, Canada
| | - Shilei Ding
- Centre de Recherche du CHUM, Montreal, QC, H2X 0A9, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, QC, H2X 0A9, Canada
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, QC, H2X 0A9, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, QC, H2X 0A9, Canada; Department of Microbiology and Immunology, McGill University, Montreal, QC, H3A 2B4, Canada.
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18
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Hu D, Bowder D, Wei W, Thompson J, Wilson MA, Xiang SH. Tryptophan 375 stabilizes the outer-domain core of gp120 for HIV vaccine immunogen design. Vaccine 2017; 35:3067-3075. [PMID: 28461065 PMCID: PMC5440730 DOI: 10.1016/j.vaccine.2017.04.054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 04/13/2017] [Accepted: 04/18/2017] [Indexed: 01/29/2023]
Abstract
VRC01 epitope focused structure-based immunogen design. Gp120 outer-domain core was further stabilized by 375 tryptophan substitution. Epitope specific antibodies were predominately induced through guinea pig immunizations.
The outer-domain core of gp120 may serve as a better HIV vaccine immunogen than the full-length gp120 because of its greater stability and immunogenicity. In our previous report, we introduced two disulfide bonds to the outer-domain core of gp120 to fix its conformation into a CD4-bound state, which resulted in a significant increase in its immunogenicity when compared to the wild-type outer-domain core. In this report, to further improve the immunogenicity of the outer-domain core based immunogen, we have introduced a Tryptophan residue at gp120 amino acid sequence position 375 (375S/W). Our data from immunized guinea pigs indeed shows a striking increase in the immune response due to this stabilized core outer-domain. Therefore, we conclude that the addition of 375W to the outer-domain core of gp120 further stabilizes the structure of immunogen and increases the immunogenicity.
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Affiliation(s)
- Duoyi Hu
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68583, United States; School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
| | - Dane Bowder
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68583, United States; School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
| | - Wenzhong Wei
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68583, United States; School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
| | - Jesse Thompson
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68583, United States; School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
| | - Mark A Wilson
- Department of Biochemistry and Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
| | - Shi-Hua Xiang
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68583, United States; School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States.
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19
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Influence of the Envelope gp120 Phe 43 Cavity on HIV-1 Sensitivity to Antibody-Dependent Cell-Mediated Cytotoxicity Responses. J Virol 2017; 91:JVI.02452-16. [PMID: 28100618 DOI: 10.1128/jvi.02452-16] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 01/12/2017] [Indexed: 01/29/2023] Open
Abstract
HIV-1-infected cells presenting envelope glycoproteins (Env) in the CD4-bound conformation on their surface are preferentially targeted by antibody-dependent cellular-mediated cytotoxicity (ADCC). HIV-1 has evolved sophisticated mechanisms to avoid the exposure of Env ADCC epitopes by downregulating CD4 and by limiting the overall amount of Env on the cell surface. In HIV-1, substitution of large residues such as histidine or tryptophan for serine 375 (S375H/W) in the gp120 Phe 43 cavity, where Phe 43 of CD4 contacts gp120, results in the spontaneous sampling of an Env conformation closer to the CD4-bound state. While residue S375 is well conserved in the majority of group M HIV-1 isolates, CRF01_AE strains have a naturally occurring histidine at this position (H375). Interestingly, CRF01_AE is the predominant circulating strain in Thailand, where the RV144 trial took place. In this trial, which resulted in a modest degree of protection, ADCC responses were identified as being part of the correlate of protection. Here we investigate the influence of the Phe 43 cavity on ADCC responses. Filling this cavity with a histidine or tryptophan residue in Env with a natural serine residue at this position (S375H/W) increased the susceptibility of HIV-1-infected cells to ADCC. Conversely, the replacement of His 375 by a serine residue (H375S) within HIV-1 CRF01_AE decreased the efficiency of the ADCC response. Our results raise the intriguing possibility that the presence of His 375 in the circulating strain where the RV144 trial was held contributed to the observed vaccine efficacy.IMPORTANCE HIV-1-infected cells presenting Env in the CD4-bound conformation on their surface are preferentially targeted by ADCC mediated by HIV-positive (HIV+) sera. Here we show that the gp120 Phe 43 cavity modulates the propensity of Env to sample this conformation and therefore affects the susceptibility of infected cells to ADCC. CRF01_AE HIV-1 strains have an unusual Phe 43 cavity-filling His 375 residue, which increases the propensity of Env to sample the CD4-bound conformation, thereby increasing susceptibility to ADCC.
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20
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The V3 Loop of HIV-1 Env Determines Viral Susceptibility to IFITM3 Impairment of Viral Infectivity. J Virol 2017; 91:JVI.02441-16. [PMID: 28100616 DOI: 10.1128/jvi.02441-16] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 01/11/2017] [Indexed: 01/09/2023] Open
Abstract
Interferon-inducible transmembrane proteins (IFITMs) inhibit a broad spectrum of viruses, including HIV-1. IFITM proteins deter HIV-1 entry when expressed in target cells and also impair HIV-1 infectivity when expressed in virus producer cells. However, little is known about how viruses resist IFITM inhibition. In this study, we have investigated the susceptibilities of different primary isolates of HIV-1 to the inhibition of viral infectivity by IFITMs. Our results demonstrate that the infectivity of different HIV-1 primary isolates, including transmitted founder viruses, is diminished by IFITM3 to various levels, with strain AD8-1 exhibiting strong resistance. Further mutagenesis studies revealed that HIV-1 Env, and the V3 loop sequence in particular, determines the extent of inhibition of viral infectivity by IFITM3. IFITM3-sensitive Env proteins are also more susceptible to neutralization by soluble CD4 or the 17b antibody than are IFITM3-resistant Env proteins. Together, data from our study suggest that the propensity of HIV-1 Env to sample CD4-bound-like conformations modulates viral sensitivity to IFITM3 inhibition.IMPORTANCE Results of our study have revealed the key features of the HIV-1 envelope protein that are associated with viral resistance to the IFITM3 protein. IFITM proteins are important effectors in interferon-mediated antiviral defense. A variety of viruses are inhibited by IFITMs at the virus entry step. Although it is known that envelope proteins of several different viruses resist IFITM inhibition, the detailed mechanisms are not fully understood. Taking advantage of the fact that envelope proteins of different HIV-1 strains exhibit different degrees of resistance to IFITM3 and that these HIV-1 envelope proteins share the same domain structure and similar sequences, we performed mutagenesis studies and determined the key role of the V3 loop in this viral resistance phenotype. We were also able to associate viral resistance to IFITM3 inhibition with the susceptibility of HIV-1 to inhibition by soluble CD4 and the 17b antibody that recognizes CD4-binding-induced epitopes.
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21
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Residues in the gp41 Ectodomain Regulate HIV-1 Envelope Glycoprotein Conformational Transitions Induced by gp120-Directed Inhibitors. J Virol 2017; 91:JVI.02219-16. [PMID: 28003492 DOI: 10.1128/jvi.02219-16] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 12/15/2016] [Indexed: 01/08/2023] Open
Abstract
Interactions between the gp120 and gp41 subunits of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) trimer maintain the metastable unliganded form of the viral spike. Binding of gp120 to the receptor, CD4, changes the Env conformation to promote gp120 interaction with the second receptor, CCR5 or CXCR4. CD4 binding also induces the transformation of Env into the prehairpin intermediate, in which the gp41 heptad repeat 1 (HR1) coiled coil is assembled at the trimer axis. In nature, HIV-1 Envs must balance the requirements to maintain the noncovalent association of gp120 with gp41 and to evade the host antibody response with the need to respond to CD4 binding. Here we show that the gp41 HR1 region contributes to gp120 association with the unliganded Env trimer. Changes in particular amino acid residues in the gp41 HR1 region decreased the efficiency with which Env moved from the unliganded state. Thus, these gp41 changes decreased the sensitivity of HIV-1 to cold inactivation and ligands that require Env conformational changes to bind efficiently. Conversely, these gp41 changes increased HIV-1 sensitivity to small-molecule entry inhibitors that block Env conformational changes induced by CD4. Changes in particular gp41 HR1 amino acid residues can apparently affect the relative stability of the unliganded state and CD4-induced conformations. Thus, the gp41 HR1 region contributes to the association with gp120 and regulates Env transitions from the unliganded state to downstream conformations.IMPORTANCE The development of an efficient vaccine able to prevent HIV infection is a worldwide priority. Knowledge of the envelope glycoprotein structure and the conformational changes that occur after receptor engagement will help researchers to develop an immunogen able to elicit antibodies that block HIV-1 transmission. Here we identify residues in the HIV-1 transmembrane envelope glycoprotein that stabilize the unliganded state by modulating the transitions from the unliganded state to the CD4-bound state.
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22
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Histidine 375 Modulates CD4 Binding in HIV-1 CRF01_AE Envelope Glycoproteins. J Virol 2017; 91:JVI.02151-16. [PMID: 27928014 DOI: 10.1128/jvi.02151-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 11/29/2016] [Indexed: 01/11/2023] Open
Abstract
The envelope glycoproteins (Envs) from human immunodeficiency virus type 1 (HIV-1) mediate viral entry. The binding of the HIV-1 gp120 glycoprotein to CD4 triggers conformational changes in gp120 that allow high-affinity binding to its coreceptors. In contrast to all other Envs from the same phylogenetic group, M, which possess a serine (S) at position 375, those from CRF01_AE strains possess a histidine (H) at this location. This residue is part of the Phe43 cavity, where residue 43 of CD4 (a phenylalanine) engages with gp120. Here we evaluated the functional consequences of replacing this residue in two CRF01_AE Envs (CM244 and 92TH023) by a serine. We observed that reversion of amino acid 375 to a serine (H375S) resulted in a loss of functionality of both CRF01_AE Envs as measured by a dramatic loss in infectivity and ability to mediate cell-to-cell fusion. While no effects on processing or trimer stability of these variants were observed, decreased functionality could be linked to a major defect in CD4 binding induced by the replacement of H375 by a serine. Importantly, mutations of residues 61 (layer 1), 105 and 108 (layer 2), and 474 to 476 (layer 3) of the CRF01_AE gp120 inner domain layers to the consensus residues present in group M restored CD4 binding and wild-type levels of infectivity and cell-to-cell fusion. These results suggest a functional coevolution between the Phe43 cavity and the gp120 inner domain layers. Altogether, our observations describe the functional importance of amino acid 375H in CRF01_AE envelopes. IMPORTANCE A highly conserved serine located at position 375 in group M is replaced by a histidine in CRF01_AE Envs. Here we show that H375 is required for efficient CRF01_AE Env binding to CD4. Moreover, this work suggests that specific residues of the gp120 inner domain layers have coevolved with H375 in order to maintain its ability to mediate viral entry.
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23
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HIV-1 Escape from a Peptidic Anchor Inhibitor through Stabilization of the Envelope Glycoprotein Spike. J Virol 2016; 90:10587-10599. [PMID: 27654295 DOI: 10.1128/jvi.01616-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 08/31/2016] [Indexed: 12/17/2022] Open
Abstract
The trimeric HIV-1 envelope glycoprotein spike (Env) mediates viral entry into cells by using a spring-loaded mechanism that allows for the controlled insertion of the Env fusion peptide into the target membrane, followed by membrane fusion. Env is the focus of vaccine research aimed at inducing protective immunity by antibodies as well as efforts to develop drugs that inhibit the viral entry process. The molecular factors contributing to Env stability and decay need to be understood better in order to optimally design vaccines and therapeutics. We generated viruses with resistance to VIR165, a peptidic inhibitor that binds the fusion peptide of the gp41 subunit and prevents its insertion into the target membrane. Interestingly, a number of escape viruses acquired substitutions in the C1 domain of the gp120 subunit (A60E, E64K, and H66R) that rendered these viruses dependent on the inhibitor. These viruses could infect target cells only when VIR165 was present after CD4 binding. Furthermore, the VIR165-dependent viruses were resistant to soluble CD4-induced Env destabilization and decay. These data suggest that VIR165-dependent Env proteins are kinetically trapped in the unliganded state and require the drug to negotiate CD4-induced conformational changes. These studies provide mechanistic insight into the action of the gp41 fusion peptide and its inhibitors and provide new ways to stabilize Env trimer vaccines. IMPORTANCE Because of the rapid development of HIV-1 drug resistance, new drug targets need to be explored continuously. The fusion peptide of the envelope glycoprotein can be targeted by anchor inhibitors. Here we describe virus escape from the anchor inhibitor VIR165. Interestingly, some escape viruses became dependent on the inhibitor for cell entry. We show that the identified escape mutations stabilize the ground state of the envelope glycoprotein and should thus be useful in the design of stabilized envelope-based HIV vaccines.
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24
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Lineage-Specific Differences between the gp120 Inner Domain Layer 3 of Human Immunodeficiency Virus and That of Simian Immunodeficiency Virus. J Virol 2016; 90:10065-10073. [PMID: 27535053 DOI: 10.1128/jvi.01215-16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/11/2016] [Indexed: 01/16/2023] Open
Abstract
Binding of human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV) gp120 exterior envelope glycoprotein to CD4 triggers conformational changes in gp120 that promote its interaction with one of the chemokine receptors, usually CCR5, ultimately leading to gp41-mediated virus-cell membrane fusion and entry. We previously described that topological layers (layer 1, layer 2, and layer 3) in the gp120 inner domain contribute to gp120-trimer association in the unliganded state but also help secure CD4 binding. Relative to layer 1 of HIV-1 gp120, the SIVmac239 gp120 layer 1 plays a more prominent role in maintaining gp120-trimer association but is minimally involved in promoting CD4 binding, which could be explained by the existence of a well-conserved tryptophan at position 375 (Trp 375) in HIV-2/SIVsmm. In this study, we investigated the role of SIV layer 3 in viral entry, cell-to-cell fusion, and CD4 binding. We observed that a network of interactions involving some residues of the β8-α5 region in SIVmac239 layer 3 may contribute to CD4 binding by helping shape the nearby Phe 43 cavity, which directly contacts CD4. In summary, our results suggest that layer 3 in SIV has a greater impact on CD4 binding than in HIV-1. This work defines lineage-specific differences in layer 3 from HIV-1 and that from SIV. IMPORTANCE CD4-induced conformational changes in the gp120 inner domain involve rearrangements between three topological layers. While the role of layers 1 to 3 for HIV-1 and layers 1 and 2 for SIV on gp120 transition to the CD4-bound conformation has been reported, the role of SIV layer 3 remains unknown. Here we report that SIV layer 3 has a greater impact on CD4 binding than does layer 3 in HIV-1 gp120. This work defines lineage-specific differences in layer 3 from HIV-1 and SIV.
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A Highly Conserved gp120 Inner Domain Residue Modulates Env Conformation and Trimer Stability. J Virol 2016; 90:8395-409. [PMID: 27384653 DOI: 10.1128/jvi.01068-16] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 06/27/2016] [Indexed: 12/11/2022] Open
Abstract
Previous studies have shown that highly conserved residues in the inner domain of gp120 are required for HIV-1 envelope glycoprotein (Env) transitions to the CD4-bound conformation (A. Finzi, S. H. Xiang, B. Pacheco, L. Wang, J. Haight, et al., Mol Cell 37:656-667, 2010, http://dx.doi.org/10.1016/j.molcel.2010.02.012; A. Desormeaux, M. Coutu, H. Medjahed, B. Pacheco, A. Herschhorn, et al., J Virol 87:2549-2562, 2013, http://dx.doi.org/10.1128/JVI.03104-12). Moreover, W69, a highly conserved residue located at the interface between layer 1 and layer 2 of the inner domain, was recently shown to be important for efficient Env recognition by CD4-induced (CD4i) antibodies capable of potent antibody-dependent cellular cytotoxicity (W. D. Tolbert, N. Gohain, M. Veillette, J. P. Chapleau, C. Orlandi, et al., 2016, Structure 24:697-709, http://dx.doi.org/10.1016/j.str.2016.03.005; S. Ding, M. Veillette, M. Coutu, J. Prevost, L. Scharf, et al., 2016, J Virol 90:2127-2134, http://dx.doi.org/10.1128/JVI.02779-15). We evaluated the contribution of the hydrophobicity of W69 to conformational changes of Env by replacing it with a series of residues with aliphatic or aromatic side chains of decreasing chain length. We have found that the hydrophobicity of residue 69 is important for Env processing, CD4 binding, and its transition to the CD4-bound conformation. The most deleterious effect was observed when W69 was replaced with alanine or glycine residues. However, the functions lost due to W69 mutations could be progressively restored with amino acids of increasing aliphatic chain length and fully recovered with residues bearing an aromatic ring. Interestingly, poor CD4 binding of W69A could be fully restored by introducing a compensatory mutation within layer 2 (S115W). Structural studies of HIV-1 gp120 coree W69A/S115W mutant bound to the CD4 peptide mimetic M48U1 and Fab of anti-cluster A antibody N60-i3 revealed no perturbations to the overall structure of the double mutant compared to the wild-type protein but identified higher mobility within the interface between layer 1 and layer 2, the bridging sheet region, and the CD4 binding site.IMPORTANCE HIV-1 Env transitions to the CD4-bound conformation are required for viral entry. Previous studies identified a highly conserved residue of the inner domain, W69, as being involved in these conformational transitions (A. Finzi, S. H. Xiang, B. Pacheco, L. Wang, J. Haight, et al., Mol Cell 37:656-667, 2010, http://dx.doi.org/10.1016/j.molcel.2010.02.012). Here, we show that W69, located at the interface between gp120 and gp41 in the PGT151-bound trimer, plays a critical role in the interprotomer signaling induced by CD4 binding. This new information might be useful in immunogen design.
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Li H, Wang S, Kong R, Ding W, Lee FH, Parker Z, Kim E, Learn GH, Hahn P, Policicchio B, Brocca-Cofano E, Deleage C, Hao X, Chuang GY, Gorman J, Gardner M, Lewis MG, Hatziioannou T, Santra S, Apetrei C, Pandrea I, Alam SM, Liao HX, Shen X, Tomaras GD, Farzan M, Chertova E, Keele BF, Estes JD, Lifson JD, Doms RW, Montefiori DC, Haynes BF, Sodroski JG, Kwong PD, Hahn BH, Shaw GM. Envelope residue 375 substitutions in simian-human immunodeficiency viruses enhance CD4 binding and replication in rhesus macaques. Proc Natl Acad Sci U S A 2016; 113:E3413-22. [PMID: 27247400 PMCID: PMC4914158 DOI: 10.1073/pnas.1606636113] [Citation(s) in RCA: 150] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Most simian-human immunodeficiency viruses (SHIVs) bearing envelope (Env) glycoproteins from primary HIV-1 strains fail to infect rhesus macaques (RMs). We hypothesized that inefficient Env binding to rhesus CD4 (rhCD4) limits virus entry and replication and could be enhanced by substituting naturally occurring simian immunodeficiency virus Env residues at position 375, which resides at a critical location in the CD4-binding pocket and is under strong positive evolutionary pressure across the broad spectrum of primate lentiviruses. SHIVs containing primary or transmitted/founder HIV-1 subtype A, B, C, or D Envs with genotypic variants at residue 375 were constructed and analyzed in vitro and in vivo. Bulky hydrophobic or basic amino acids substituted for serine-375 enhanced Env affinity for rhCD4, virus entry into cells bearing rhCD4, and virus replication in primary rhCD4 T cells without appreciably affecting antigenicity or antibody-mediated neutralization sensitivity. Twenty-four RMs inoculated with subtype A, B, C, or D SHIVs all became productively infected with different Env375 variants-S, M, Y, H, W, or F-that were differentially selected in different Env backbones. Notably, SHIVs replicated persistently at titers comparable to HIV-1 in humans and elicited autologous neutralizing antibody responses typical of HIV-1. Seven animals succumbed to AIDS. These findings identify Env-rhCD4 binding as a critical determinant for productive SHIV infection in RMs and validate a novel and generalizable strategy for constructing SHIVs with Env glycoproteins of interest, including those that in humans elicit broadly neutralizing antibodies or bind particular Ig germ-line B-cell receptors.
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Affiliation(s)
- Hui Li
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Shuyi Wang
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Rui Kong
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Wenge Ding
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Fang-Hua Lee
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Zahra Parker
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Eunlim Kim
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Gerald H Learn
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Paul Hahn
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Ben Policicchio
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA 15261
| | | | - Claire Deleage
- AIDS and Cancer Virus Program, Leidos Biomedical Research Inc., Frederick National Laboratory, Frederick, MD 21702
| | - Xingpei Hao
- AIDS and Cancer Virus Program, Leidos Biomedical Research Inc., Frederick National Laboratory, Frederick, MD 21702
| | - Gwo-Yu Chuang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Jason Gorman
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Matthew Gardner
- Department of Infectious Disease, Scripps Research Institute, Jupiter, FL 33458
| | | | | | - Sampa Santra
- Center of Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Boston, MA 02215
| | - Cristian Apetrei
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA 15261
| | - Ivona Pandrea
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA 15261
| | - S Munir Alam
- Department of Medicine, Duke University, Durham, NC 27710
| | - Hua-Xin Liao
- Department of Medicine, Duke University, Durham, NC 27710
| | - Xiaoying Shen
- Department of Medicine, Duke University, Durham, NC 27710
| | | | - Michael Farzan
- Department of Infectious Disease, Scripps Research Institute, Jupiter, FL 33458
| | - Elena Chertova
- AIDS and Cancer Virus Program, Leidos Biomedical Research Inc., Frederick National Laboratory, Frederick, MD 21702
| | - Brandon F Keele
- AIDS and Cancer Virus Program, Leidos Biomedical Research Inc., Frederick National Laboratory, Frederick, MD 21702
| | - Jacob D Estes
- AIDS and Cancer Virus Program, Leidos Biomedical Research Inc., Frederick National Laboratory, Frederick, MD 21702
| | - Jeffrey D Lifson
- AIDS and Cancer Virus Program, Leidos Biomedical Research Inc., Frederick National Laboratory, Frederick, MD 21702
| | - Robert W Doms
- Department of Pathology, Children's Hospital of Philadelphia, Philadelphia, PA 19104
| | | | | | - Joseph G Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215
| | - Peter D Kwong
- AIDS and Cancer Virus Program, Leidos Biomedical Research Inc., Frederick National Laboratory, Frederick, MD 21702
| | - Beatrice H Hahn
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104;
| | - George M Shaw
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104;
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Development of Broadly Neutralizing Antibodies and Their Mapping by Monomeric gp120 in Human Immunodeficiency Virus Type 1-Infected Humans and Simian-Human Immunodeficiency Virus SHIVSF162P3N-Infected Macaques. J Virol 2016; 90:4017-4031. [PMID: 26842476 DOI: 10.1128/jvi.02898-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 01/28/2016] [Indexed: 12/24/2022] Open
Abstract
UNLABELLED To improve our understanding of the similarities and differences between neutralizing antibodies elicited by simian-human immunodeficiency virus (SHIV)-infected rhesus macaques and human immunodeficiency virus type 1 (HIV-1)-infected humans, we examined the plasma of 13 viremic macaques infected with SHIVSF162P3Nand 85 HIV-1-infected humans with known times of infection. We identified 5 macaques (38%) from 1 to 2 years postinfection (p.i.) with broadly neutralizing antibodies (bnAbs) against tier 2 HIV-1. In comparison, only 2 out of 42 (5%) human plasma samples collected in a similar time frame of 1 to 3 years p.i. exhibited comparable neutralizing breadths and potencies, with the number increasing to 7 out of 21 (30%) after 3 years p.i. Plasma mapping with monomeric gp120 identified only 2 out of 9 humans and 2 out of 4 macaques that contained gp120-reactive neutralizing antibodies, indicating distinct specificities in these plasma samples, with most of them recognizing the envelope trimer (including gp41) rather than the gp120 monomer. Indeed, a total of 20 gp120-directed monoclonal antibodies (MAbs) isolated from a human subject (AD358) and a Chinese rhesus macaque (GB40) displayed no or limited neutralizing activity against tier 2 strains. These isolated MAbs, mapped to the CD4-binding site, the V3 loop, the inner domain, and the C5 region of gp120, revealed genetic similarity between the human and macaque immunoglobulin genes used to encode some V3-directed MAbs. These results also support the use of envelope trimer probes for efficient isolation of HIV-1 bnAbs. IMPORTANCE HIV-1 vaccine research can benefit from understanding the development of broadly neutralizing antibodies (bnAbs) in rhesus macaques, commonly used to assess vaccine immunogenicity and efficacy. Here, we examined 85 HIV-1-infected humans and 13 SHIVSF162P3N-infected macaques for bnAbs and found that, similar to HIV-1-infected humans, bnAbs in SHIV-infected macaques are also rare, but their development might have been faster in some of the studied macaques. Plasma mapping with monomeric gp120 indicated that most bnAbs bind to the envelope trimer rather than the gp120 monomer. In support of this, none of the isolated gp120-reactive monoclonal antibodies (MAbs) displayed the neutralization breadth observed in the corresponding plasma. However, the MAb sequences revealed similarity between human and macaque genes used to encode some V3-directed MAbs. Our study sheds light on the timing and development of bnAbs in SHIV-infected macaques in comparison to HIV-1-infected humans and highlights the use of envelope trimer probes for efficient recovery of bnAbs.
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Nef Proteins from HIV-1 Elite Controllers Are Inefficient at Preventing Antibody-Dependent Cellular Cytotoxicity. J Virol 2015; 90:2993-3002. [PMID: 26719277 DOI: 10.1128/jvi.02973-15] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 12/22/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Impairment of Nef function, including reduced CD4 downregulation, was described in a subset of HIV-1-infected individuals that control viral replication without antiretroviral treatment (elite controllers [EC]). Elimination of HIV-1-infected cells by antibody-dependent cellular cytotoxicity (ADCC) requires the presence of envelope glycoproteins (Env) in the CD4-bound conformation, raising the possibility that accumulating CD4 at the surface of virus-infected cells in EC could interact with Env and thereby sensitize these cells to ADCC. We observed a significant increase in the exposure of Env epitopes targeted by ADCC-mediating antibodies at the surface of cells expressing Nef isolates from EC; this correlated with enhanced susceptibility to ADCC. Altogether, our results suggest that enhanced susceptibility of HIV-1-infected cells to ADCC may contribute to the EC phenotype. IMPORTANCE Nef clones derived from elite controllers (EC) have been shown to be attenuated for CD4 downregulation; how this contributes to the nonprogressor phenotype of these infected individuals remains uncertain. Increasing evidence supports a role for HIV-specific antibody-dependent cellular cytotoxicity (ADCC) in controlling viral infection and replication. Here, we show that residual CD4 left at the surface of cells expressing Nef proteins isolated from ECs are sufficient to allow Env-CD4 interaction, leading to increased exposure of Env CD4-induced epitopes and increased susceptibility of infected cells to ADCC. Our results suggest that ADCC might be an active immune mechanism in EC that helps to maintain durable suppression of viral replication and low plasma viremia level in this rare subset of infected individuals. Therefore, targeting Nef's ability to downregulate CD4 could render HIV-1-infected cells susceptible to ADCC and thus have therapeutic utility.
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Aneja R, Rashad AA, Li H, Kalyana Sundaram RV, Duffy C, Bailey LD, Chaiken I. Peptide Triazole Inactivators of HIV-1 Utilize a Conserved Two-Cavity Binding Site at the Junction of the Inner and Outer Domains of Env gp120. J Med Chem 2015; 58:3843-58. [PMID: 25860784 DOI: 10.1021/acs.jmedchem.5b00073] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
We used coordinated mutagenesis, synthetic design, and flexible docking to investigate the structural mechanism of Env gp120 encounter by peptide triazole (PT) inactivators of HIV-1. Prior results demonstrated that the PT class of inhibitors suppresses binding at both CD4 and coreceptor sites on Env and triggers gp120 shedding, leading to cell-independent irreversible virus inactivation. Despite these enticing anti-HIV-1 phenotypes, structural understanding of the PT-gp120 binding mechanism has been incomplete. Here we found that PT engages two inhibitor ring moieties at the junction between the inner and outer domains of the gp120 protein. The results demonstrate how combined occupancy of two gp120 cavities can coordinately suppress both receptor and coreceptor binding and conformationally entrap the protein in a destabilized state. The two-cavity model has common features with small molecule gp120 inhibitor binding sites and provides a guide for further design of peptidomimetic HIV-1 inactivators based on the PT pharmacophore.
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Affiliation(s)
- Rachna Aneja
- †Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Adel A Rashad
- †Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Huiyuan Li
- †Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Ramalingam Venkat Kalyana Sundaram
- †Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States.,‡School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Caitlin Duffy
- †Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Lauren D Bailey
- †Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Irwin Chaiken
- †Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
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Effects of the I559P gp41 change on the conformation and function of the human immunodeficiency virus (HIV-1) membrane envelope glycoprotein trimer. PLoS One 2015; 10:e0122111. [PMID: 25849367 PMCID: PMC4388519 DOI: 10.1371/journal.pone.0122111] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 02/20/2015] [Indexed: 12/21/2022] Open
Abstract
The mature human immunodeficiency virus (HIV-1) envelope glycoprotein (Env) trimer is produced by proteolytic cleavage of a precursor and consists of three gp120 exterior and three gp41 transmembrane subunits. The metastable Env complex is induced to undergo conformational changes required for virus entry by the binding of gp120 to the receptors, CD4 and CCR5/CXCR4. An isoleucine-to-proline change (I559P) in the gp41 ectodomain has been used to stabilize soluble forms of HIV-1 Env trimers for structural characterization and for use as immunogens. In the native membrane-anchored HIV-1BG505 Env, the I559P change modestly decreased proteolytic maturation, increased the non-covalent association of gp120 with the Env trimer, and resulted in an Env conformation distinctly different from that of the wild-type HIV-1BG505 Env. Compared with the wild-type Env, the I559P Env was recognized inefficiently by polyclonal sera from HIV-1-infected individuals, by several gp41-directed antibodies, by some antibodies against the CD4-binding site of gp120, and by antibodies that preferentially recognize the CD4-bound Env. Some of the gp120-associated antigenic differences between the wild-type HIV-1BG505 Env and the I559P mutant were compensated by the SOS disulfide bond between gp120 and gp41, which has been used to stabilize cleaved soluble Env trimers. Nonetheless, regardless of the presence of the SOS changes, Envs with proline 559 were recognized less efficiently than Envs with isoleucine 559 by the VRC01 neutralizing antibody, which binds the CD4-binding site of gp120, and the PGT151 neutralizing antibody, which binds a hybrid gp120-gp41 epitope. The I559P change completely eliminated the ability of the HIV-1BG505 Env to mediate cell-cell fusion and virus entry, and abolished the capacity of the SOS Env to support virus infection in the presence of a reducing agent. These results suggest that differences exist between the quaternary structures of functional Env spikes and I559P Envs.
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Zhao Y, Wang Y, Gao Y, Li G, Huang J. Integrated analysis of residue coevolution and protein structures capture key protein sectors in HIV-1 proteins. PLoS One 2015; 10:e0117506. [PMID: 25671429 PMCID: PMC4324911 DOI: 10.1371/journal.pone.0117506] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 12/24/2014] [Indexed: 02/07/2023] Open
Abstract
HIV type 1 (HIV-1) is characterized by its rapid genetic evolution, leading to challenges in anti-HIV therapy. However, the sequence variations in HIV-1 proteins are not randomly distributed due to a combination of functional constraints and genetic drift. In this study, we examined patterns of sequence variability for evidence of linked sequence changes (termed as coevolution or covariation) in 15 HIV-1 proteins. It shows that the percentage of charged residues in the coevolving residues is significantly higher than that in all the HIV-1 proteins. Most of the coevolving residues are spatially proximal in the protein structures and tend to form relatively compact and independent units in the tertiary structures, termed as "protein sectors". These protein sectors are closely associated with anti-HIV drug resistance, T cell epitopes, and antibody binding sites. Finally, we explored candidate peptide inhibitors based on the protein sectors. Our results can establish an association between the coevolving residues and molecular functions of HIV-1 proteins, and then provide us with valuable knowledge of pathology of HIV-1 and therapeutics development.
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Affiliation(s)
- Yuqi Zhao
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, No.32 Jiaochang Donglu Kunming, 650223 Yunnan, China
- Department of Integrative Biology and Physiology, University of California, Los Angeles, 610 Charles E. Young Drive East, Los Angeles, California, United States of America
- * E-mail: (YZ); (JH)
| | - Yanjie Wang
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Yuedong Gao
- Kunming Biological Diversity Regional Center of Instruments, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Gonghua Li
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, No.32 Jiaochang Donglu Kunming, 650223 Yunnan, China
| | - Jingfei Huang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, No.32 Jiaochang Donglu Kunming, 650223 Yunnan, China
- Collaborative Innovation Center for Natural Products and Biological Drugs of Yunnan, Kunming, Yunnan 650223, China
- * E-mail: (YZ); (JH)
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Batraville LA, Richard J, Veillette M, Labbé AC, Alary M, Guédou F, Kaufmann DE, Poudrier J, Finzi A, Roger M. Short communication: Anti-HIV-1 envelope immunoglobulin Gs in blood and cervicovaginal samples of Beninese commercial sex workers. AIDS Res Hum Retroviruses 2014; 30:1145-9. [PMID: 25354025 DOI: 10.1089/aid.2014.0163] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Characterization of the immune correlates of protection against HIV infection is crucial for the development of preventive strategies. This study examined HIV-1 envelope (Env) glycoproteins, specifically immunoglobulin G (IgG), in systemic and mucosal compartments of female Beninese commercial sex workers (CSWs). Samples of 23 HIV-1-positive and 20 highly exposed HIV-1-seronegative (HESN) CSWs were studied. HIV-1 Env-specific IgG detection in sera and cervicovaginal lavages (CVLs) from the study population was done by cell-based ELISA. The HIV neutralizing activity was evaluated with a neutralization assay. The HIV-1-specific antibody-dependent cellular cytotoxicity (ADCC) response of the cohort was measured with a FACS-based assay evaluating the ADCC-mediated elimination of gp120-coated target cells. No anti-HIV-1 Env-specific IgG neutralizing or ADCC activities were detected in samples from HESN CSWs. Samples from HIV-1-infected CSWs presented ADCC activity in both sera and CVLs. Anti-Env IgG from sera and CVLs from HIV-1-infected CSWs preferentially recognized Env in its CD4-bound conformation. HIV-1-infected CSWs have ADCC-mediating IgG that preferentially recognizes Env in its CD4-bound conformation at the mucosal site.
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Affiliation(s)
- Laurie-Anne Batraville
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Jonathan Richard
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Maxime Veillette
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Annie-Claude Labbé
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Michel Alary
- Centre de Recherche du CHU de Québec, Québec, Québec, Canada
- Département de Médecine Sociale et Préventive, Université Laval, Québec, Québec, Canada
| | | | - Daniel E. Kaufmann
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
- Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts
| | - Johanne Poudrier
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Andrés Finzi
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Québec, Canada
| | - Michel Roger
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
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The HIV-1 gp120 CD4-bound conformation is preferentially targeted by antibody-dependent cellular cytotoxicity-mediating antibodies in sera from HIV-1-infected individuals. J Virol 2014; 89:545-51. [PMID: 25339767 DOI: 10.1128/jvi.02868-14] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Recent studies have linked antibody Fc-mediated effector functions with protection or control of human immunodeficiency type 1 (HIV-1) and simian immunodeficiency (SIV) infections. Interestingly, the presence of antibodies with potent antibody-dependent cellular cytotoxicity (ADCC) activity in the Thai RV144 vaccine trial was suggested to correlate with decreased HIV-1 acquisition risk. These antibodies recently were found to recognize HIV envelope (Env) epitopes exposed upon Env-CD4 interaction. CD4 downregulation by Nef and Vpu, as well as Vpu-mediated BST-2 antagonism, were reported to modulate exposure of those CD4-induced HIV-1 Env epitopes and were proposed to play a role in reducing the susceptibility of infected cells to ADCC mediated by this class of antibodies. Here, we report the high prevalence of antibodies recognizing CD4-induced HIV-1 Env epitopes in sera from HIV-1-infected individuals, which correlated with their ability to mediate ADCC responses against HIV-1-infected cells, exposing these Env epitopes at the cell surface. Furthermore, our results indicate that Env variable regions V1, V2, V3, and V5 do not represent a major determinant for ADCC responses mediated by sera from HIV-1-infected individuals. Altogether, these findings suggest that HIV-1 tightly controls the exposure of certain Env epitopes at the surface of infected cells in order to prevent elimination by Fc-effector functions. IMPORTANCE Here, we identified a particular conformation of HIV-1 Env that is specifically targeted by ADCC-mediating antibodies present in sera from HIV-1-infected individuals. This observation suggests that HIV-1 developed sophisticated mechanisms to minimize the exposure of these epitopes at the surface of infected cells.
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Slaying the Trojan horse: natural killer cells exhibit robust anti-HIV-1 antibody-dependent activation and cytolysis against allogeneic T cells. J Virol 2014; 89:97-109. [PMID: 25320293 DOI: 10.1128/jvi.02461-14] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED Many attempts to design prophylactic human immunodeficiency virus type 1 (HIV-1) vaccines have focused on the induction of neutralizing antibodies (Abs) that block infection by free virions. Despite the focus on viral particles, virus-infected cells, which can be found within mucosal secretions, are more infectious than free virus both in vitro and in vivo. Furthermore, assessment of human transmission couples suggests infected seminal lymphocytes might be responsible for a proportion of HIV-1 transmissions. Although vaccines that induce neutralizing Abs are sought, only some broadly neutralizing Abs efficiently block cell-to-cell transmission of HIV-1. As HIV-1 vaccines need to elicit immune responses capable of controlling both free and cell-associated virus, we evaluated the potential of natural killer (NK) cells to respond in an Ab-dependent manner to allogeneic T cells bearing HIV-1 antigens. This study presents data measuring Ab-dependent anti-HIV-1 NK cell responses to primary and transformed allogeneic T-cell targets. We found that NK cells are robustly activated in an anti-HIV-1 Ab-dependent manner against allogeneic targets and that tested target cells are subject to Ab-dependent cytolysis. Furthermore, the educated KIR3DL1(+) NK cell subset from HLA-Bw4(+) individuals exhibits an activation advantage over the KIR3DL1(-) subset that contains both NK cells educated through other receptor/ligand combinations and uneducated NK cells. These results are intriguing and important for understanding the regulation of Ab-dependent NK cell responses and are potentially valuable for designing Ab-dependent therapies and/or vaccines. IMPORTANCE NK cell-mediated anti-HIV-1 antibody-dependent functions have been associated with protection from infection and disease progression; however, their role in protecting from infection with allogeneic cells infected with HIV-1 is unknown. We found that HIV-1-specific ADCC antibodies bound to allogeneic cells infected with HIV-1 or coated with HIV-1 gp120 were capable of activating NK cells and/or trigging cytolysis of the allogeneic target cells. This suggests ADCC may be able to assist in preventing infection with cell-associated HIV-1. In order to fully utilize NK cell-mediated Ab-dependent effector functions, it might also be important that educated NK cells, which hold the highest activation potential, can become activated against targets bearing HIV-1 antigens and expressing the ligands for self-inhibitory receptors. Here, we show that with Ab-dependent stimulation, NK cells expressing inhibitory receptors can mediate robust activation against targets expressing the ligands for those receptors.
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Veillette M, Coutu M, Richard J, Batraville LA, Désormeaux A, Roger M, Finzi A. Conformational evaluation of HIV-1 trimeric envelope glycoproteins using a cell-based ELISA assay. J Vis Exp 2014:51995. [PMID: 25286159 DOI: 10.3791/51995] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
HIV-1 envelope glycoproteins (Env) mediate viral entry into target cells and are essential to the infectious cycle. Understanding how those glycoproteins are able to fuel the fusion process through their conformational changes could lead to the design of better, more effective immunogens for vaccine strategies. Here we describe a cell-based ELISA assay that allows studying the recognition of trimeric HIV-1 Env by monoclonal antibodies. Following expression of HIV-1 trimeric Env at the surface of transfected cells, conformation specific anti-Env antibodies are incubated with the cells. A horseradish peroxidase-conjugated secondary antibody and a simple chemiluminescence reaction are then used to detect bound antibodies. This system is highly flexible and can detect Env conformational changes induced by soluble CD4 or cellular proteins. It requires minimal amount of material and no highly-specialized equipment or know-how. Thus, this technique can be established for medium to high throughput screening of antigens and antibodies, such as newly-isolated antibodies.
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Affiliation(s)
- Maxime Veillette
- Centre de recherche du CHUM, Department of Microbiology, Infectiology and Immunology, Université de Montréal
| | - Mathieu Coutu
- Centre de recherche du CHUM, Department of Microbiology, Infectiology and Immunology, Université de Montréal
| | - Jonathan Richard
- Centre de recherche du CHUM, Department of Microbiology, Infectiology and Immunology, Université de Montréal
| | - Laurie-Anne Batraville
- Centre de recherche du CHUM, Department of Microbiology, Infectiology and Immunology, Université de Montréal
| | - Anik Désormeaux
- Centre de recherche du CHUM, Department of Microbiology, Infectiology and Immunology, Université de Montréal
| | - Michel Roger
- Centre de recherche du CHUM, Department of Microbiology, Infectiology and Immunology, Université de Montréal
| | - Andrés Finzi
- Centre de recherche du CHUM, Department of Microbiology, Infectiology and Immunology, Université de Montréal;
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36
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Structural definition of an antibody-dependent cellular cytotoxicity response implicated in reduced risk for HIV-1 infection. J Virol 2014; 88:12895-906. [PMID: 25165110 DOI: 10.1128/jvi.02194-14] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED The RV144 vaccine trial implicated epitopes in the C1 region of gp120 (A32-like epitopes) as targets of potentially protective antibody-dependent cellular cytotoxicity (ADCC) responses. A32-like epitopes are highly immunogenic, as infected or vaccinated individuals frequently produce antibodies specific for these determinants. Antibody titers, as measured by enzyme-linked immunosorbent assay (ELISA) against these epitopes, however, do not consistently correlate with protection. Here, we report crystal structures of CD4-stabilized gp120 cores complexed with the Fab fragments of two nonneutralizing, A32-like monoclonal antibodies (MAbs), N5-i5 and 2.2c, that compete for antigen binding and have similar antigen-binding affinities yet exhibit a 75-fold difference in ADCC potency. We find that these MAbs recognize overlapping epitopes formed by mobile layers 1 and 2 of the gp120 inner domain, including the C1 and C2 regions, but bind gp120 at different angles via juxtaposed VH and VL contact surfaces. A comparison of structural and immunological data further showed that antibody orientation on bound antigen and the capacity to form multivalent antigen-antibody complexes on target cells were key determinants of ADCC potency, with the latter process having the greater impact. These studies provide atomic-level definition of A32-like epitopes implicated as targets of protective antibodies in RV144. Moreover, these studies establish that epitope structure and mode of antibody binding can dramatically affect the potency of Fc-mediated effector function against HIV-1. These results provide key insights for understanding, refining, and improving the outcome of HIV vaccine trials, in which relevant immune responses are facilitated by A32-like elicited responses. IMPORTANCE HIV-1 Env is a primary target for antibodies elicited during infection. Although a small number of infected individuals elicit broadly neutralizing antibodies, the bulk of the humoral response consists of antibodies that do not neutralize or do so with limited breadth but may effect protection through Fc receptor-dependent processes, such as antibody-dependent cellular cytotoxicity (ADCC). Understanding these nonneutralizing responses is an important aspect of elucidating the complete spectrum of immune response against HIV-1 infection. With this report, we provide the first atomic-level definition of nonneutralizing CD4-induced epitopes in the N-terminal region of the HIV-1 gp120 (A32-like epitopes). Further, our studies point to the dominant role of precise epitope targeting and mode of antibody attachment in ADCC responses even when largely overlapping epitopes are involved. Such information provides key insights into the mechanisms of Fc-mediated function of antibodies to HIV-1 and will help us understand the outcome of vaccine trials based on humoral immunity.
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37
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Richard J, Veillette M, Batraville LA, Coutu M, Chapleau JP, Bonsignori M, Bernard N, Tremblay C, Roger M, Kaufmann DE, Finzi A. Flow cytometry-based assay to study HIV-1 gp120 specific antibody-dependent cellular cytotoxicity responses. J Virol Methods 2014; 208:107-14. [PMID: 25125129 DOI: 10.1016/j.jviromet.2014.08.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/28/2014] [Accepted: 08/01/2014] [Indexed: 11/24/2022]
Abstract
Increased attention on the role of Fc-mediated effector functions against HIV-1 has led to renewed interest into the role that antibody-dependent cellular cytotoxicity (ADCC) could play in controlling viral transmission and/or the rate of disease progression. While (51)Chromium release assays have traditionally been used to study ADCC responses against HIV-1, a number of alternative flow-cytometry-based assays were recently developed. In this study, an alternative flow-cytometry-based assay was established to allow non-radioactive measurement of ADCC-mediated elimination of HIV-1 gp120 envelope glycoprotein (Env)-coated target cells. This assay relies on staining target and effector cells with different dyes, which allows precise gating and permits the calculation of the number of surviving target cells by normalization to flow-cytometry particles. By using small concentrations of recombinant gp120 Env, suitable targets cells that recapitulate the ADCC response mediated against HIV-1-infected cells were generated. Finally, this method was applied successfully to screen human sera for ADCC activity directed against HIV-1 gp120 Env.
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Affiliation(s)
- Jonathan Richard
- Centre de Recherche du CHUM, Université de Montréal, Montreal, Quebec, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, Quebec, Canada
| | - Maxime Veillette
- Centre de Recherche du CHUM, Université de Montréal, Montreal, Quebec, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, Quebec, Canada
| | - Laurie-Anne Batraville
- Centre de Recherche du CHUM, Université de Montréal, Montreal, Quebec, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, Quebec, Canada
| | - Mathieu Coutu
- Centre de Recherche du CHUM, Université de Montréal, Montreal, Quebec, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, Quebec, Canada
| | - Jean-Philippe Chapleau
- Centre de Recherche du CHUM, Université de Montréal, Montreal, Quebec, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, Quebec, Canada
| | | | - Nicole Bernard
- Research Institute of the McGill University Health Centre, Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
| | - Cécile Tremblay
- Centre de Recherche du CHUM, Université de Montréal, Montreal, Quebec, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, Quebec, Canada; Institut National de santé publique du Québec, Canada
| | - Michel Roger
- Centre de Recherche du CHUM, Université de Montréal, Montreal, Quebec, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, Quebec, Canada
| | - Daniel E Kaufmann
- Centre de Recherche du CHUM, Université de Montréal, Montreal, Quebec, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, Quebec, Canada; Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard, Cambridge, MA, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Université de Montréal, Montreal, Quebec, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, Quebec, Canada; Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada.
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38
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Guttman M, Garcia NK, Cupo A, Matsui T, Julien JP, Sanders RW, Wilson IA, Moore JP, Lee KK. CD4-induced activation in a soluble HIV-1 Env trimer. Structure 2014; 22:974-84. [PMID: 24931470 PMCID: PMC4231881 DOI: 10.1016/j.str.2014.05.001] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 04/28/2014] [Accepted: 05/01/2014] [Indexed: 01/05/2023]
Abstract
The HIV envelope glycoprotein (Env) trimer undergoes receptor-induced conformational changes that drive fusion of the viral and cellular membranes. Env conformational changes have been observed using low-resolution electron microscopy, but only large-scale rearrangements have been visible. Here, we use hydrogen-deuterium exchange and oxidative labeling to gain a more precise understanding of the unliganded and CD4-bound forms of soluble Env trimers (SOSIP.664), including their glycan composition. CD4 activation induces the reorganization of bridging sheet elements, V1/V2 and V3, much of the gp120 inner domain, and the gp41 fusion subunit. Two CD4 binding site-targeted inhibitors have substantially different effects: NBD-556 partially mimics CD4-induced destabilization of the V1/V2 and V3 crown, whereas BMS-806 only affects regions around the gp120/gp41 interface. The structural information presented here increases our knowledge of CD4- and small molecule-induced conformational changes in Env and the allosteric pathways that lead to membrane fusion.
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Affiliation(s)
- Miklos Guttman
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Natalie K Garcia
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Albert Cupo
- Weill Medical College of Cornell University, New York, NY 10021, USA
| | - Tsutomu Matsui
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Jean-Philippe Julien
- Department of Integrative Structural and Computational Biology, International AIDS Vaccine Initiative Neutralizing Antibody Center, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, and Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Rogier W Sanders
- Weill Medical College of Cornell University, New York, NY 10021, USA; Department of Medical Microbiology, Academic Medical Center, 1105 AZ Amsterdam, the Netherlands
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, International AIDS Vaccine Initiative Neutralizing Antibody Center, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, and Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - John P Moore
- Weill Medical College of Cornell University, New York, NY 10021, USA
| | - Kelly K Lee
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA.
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39
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Li Y, Yang D, Wang JY, Yao Y, Zhang WZ, Wang LJ, Cheng DC, Yang FK, Zhang FM, Zhuang M, Ling H. Critical amino acids within the human immunodeficiency virus type 1 envelope glycoprotein V4 N- and C-terminals contribute to virus entry. PLoS One 2014; 9:e86083. [PMID: 24465884 PMCID: PMC3897638 DOI: 10.1371/journal.pone.0086083] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 12/09/2013] [Indexed: 11/22/2022] Open
Abstract
The importance of the fourth variable (V4) region of the human immunodeficiency virus 1 (HIV-1) envelope glycoprotein (Env) in virus infection has not been well clarified, though the polymorphism of this region has been found to be associated with disease progression to acquired immunodeficiency syndrome (AIDS). In the present work, we focused on the correlation between HIV-1 gp120 V4 region polymorphism and the function of the region on virus entry, and the possible mechanisms for how the V4 region contributes to virus infectivity. Therefore, we analyzed the differences in V4 sequences along with coreceptor usage preference from CCR5 to CXCR4 and examined the importance of the amino acids within the V4 region for CCR5- and CXCR4-tropic virus entry. In addition, we determined the influence of the V4 amino acids on Env expression and gp160 processing intracellularly, as well as the amount of Env on the pseudovirus surface. The results indicated that V4 tended to have a shorter length, fewer potential N-linked glycosylation sites (PNGS), greater evolutionary distance, and a lower negative net charge when HIV-1 isolates switched from a coreceptor usage preference for CCR5 to CXCR4. The N- and C-terminals of the HIV-1 V4 region are highly conserved and critical to maintain virus entry ability, but only the mutation at position 417 in the context of ADA (a R5-tropic HIV-1 strain) resulted in the ability to utilize CXCR4. In addition, 390L, 391F, 414I, and 416L are critical to maintain gp160 processing and maturation. It is likely that the hydrophobic properties and the electrostatic surface potential of gp120, rather than the conformational structure, greatly contribute to this V4 functionality. The findings provide information to aid in the understanding of the functions of V4 in HIV-1 entry and offer a potential target to aid in the development of entry inhibitors.
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Affiliation(s)
- Yan Li
- Department of Microbiology, Harbin Medical University, Harbin, China
- Heilongjiang Provincial Key Laboratory for Infection and Immunity, Key Laboratory of Etiology of Heilongjiang Province Education Bureau, Harbin, China
| | - Dan Yang
- Department of Forensic Medicine, Harbin Medical University, Harbin, China
| | - Jia-Ye Wang
- Department of Microbiology, Harbin Medical University, Harbin, China
- Heilongjiang Provincial Key Laboratory for Infection and Immunity, Key Laboratory of Etiology of Heilongjiang Province Education Bureau, Harbin, China
| | - Yuan Yao
- Academy of Fundamental and Interdisciplinary Science, Harbin Institute of Technology, Harbin, China
| | - Wei-Zhe Zhang
- Department of Parasitology, Harbin Medical University, Harbin, China
- Heilongjiang Provincial Key Laboratory for Infection and Immunity, Key Laboratory of Etiology of Heilongjiang Province Education Bureau, Harbin, China
| | - Lu-Jing Wang
- Department of Biochemistry, Harbin Medical University, Harbin, China
| | - De-Chun Cheng
- Department of Parasitology, Harbin Medical University, Harbin, China
- Heilongjiang Provincial Key Laboratory for Infection and Immunity, Key Laboratory of Etiology of Heilongjiang Province Education Bureau, Harbin, China
| | - Feng-Kun Yang
- Department of Parasitology, Harbin Medical University, Harbin, China
- Heilongjiang Provincial Key Laboratory for Infection and Immunity, Key Laboratory of Etiology of Heilongjiang Province Education Bureau, Harbin, China
| | - Feng-Min Zhang
- Department of Microbiology, Harbin Medical University, Harbin, China
- Heilongjiang Provincial Key Laboratory for Infection and Immunity, Key Laboratory of Etiology of Heilongjiang Province Education Bureau, Harbin, China
| | - Min Zhuang
- Department of Microbiology, Harbin Medical University, Harbin, China
- Heilongjiang Provincial Key Laboratory for Infection and Immunity, Key Laboratory of Etiology of Heilongjiang Province Education Bureau, Harbin, China
- * E-mail: (HL); (MZ)
| | - Hong Ling
- Department of Microbiology, Harbin Medical University, Harbin, China
- Department of Parasitology, Harbin Medical University, Harbin, China
- Heilongjiang Provincial Key Laboratory for Infection and Immunity, Key Laboratory of Etiology of Heilongjiang Province Education Bureau, Harbin, China
- * E-mail: (HL); (MZ)
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40
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Interaction with cellular CD4 exposes HIV-1 envelope epitopes targeted by antibody-dependent cell-mediated cytotoxicity. J Virol 2013; 88:2633-44. [PMID: 24352444 DOI: 10.1128/jvi.03230-13] [Citation(s) in RCA: 215] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Anti-HIV-1 envelope glycoprotein (Env) antibodies without broadly neutralizing activity correlated with protection in the RV144 clinical trial, stimulating interest in other protective mechanisms involving antibodies, such as antibody-dependent cell-mediated cytotoxicity (ADCC). Env epitopes targeted by many antibodies effective at mediating ADCC are poorly exposed on the unliganded Env trimer. Here we investigated the mechanism of exposure of ADCC epitopes on Env and showed that binding of Env and CD4 within the same HIV-1-infected cell effectively exposes these epitopes. Env capacity to transit to the CD4-bound conformation is required for ADCC epitope exposure. Importantly, cell surface CD4 downregulation by Nef and Vpu accessory proteins and Vpu-mediated BST-2 antagonism modulate exposure of ADCC-mediating epitopes and reduce the susceptibility of infected cells to this effector function in vitro. Significantly, Env conformational changes induced by cell surface CD4 are conserved among Env from HIV-1 and HIV-2/SIVmac lineages. Altogether, our observations describe a highly conserved mechanism required to expose ADCC epitopes that might help explain the evolutionary advantage of downregulation of cell surface CD4 by the HIV-1 Vpu and Nef proteins. IMPORTANCE HIV-1 envelope epitopes targeted by many antibodies effective at mediating antibody-dependent cell-mediated cytotoxicity (ADCC) are poorly exposed on the unliganded envelope trimer. Here we investigated the mechanism of exposure of these epitopes and found that envelope interaction with the HIV-1 CD4 receptor is required to expose some of these epitopes. Moreover, our results suggest that HIV-1 CD4 downregulation might help avoid the killing of HIV-1-infected cells by this immune mechanism.
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41
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Guttman M, Lee KK. A functional interaction between gp41 and gp120 is observed for monomeric but not oligomeric, uncleaved HIV-1 Env gp140. J Virol 2013; 87:11462-75. [PMID: 23966389 PMCID: PMC3807357 DOI: 10.1128/jvi.01681-13] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 08/09/2013] [Indexed: 11/20/2022] Open
Abstract
The envelope glycoprotein (Env) is the sole antigenic feature on the surface of HIV and the target for the humoral immune system. Soluble, uncleaved gp140 Env constructs truncated at the transmembrane domain are being investigated intensively as potential vaccine immunogens by many groups, and understanding their structural properties is essential. We used hydrogen/deuterium-exchange mass spectrometry and small-angle X-ray scattering to probe structural order in a panel of commonly used gp140 constructs and matched gp120 monomers. We observed that oligomeric forms of uncleaved gp140, generally presumed to be trimeric, contain a protease-resistant form of gp41 akin to the postfusion, helical bundle conformation and appear to lack specific interactions between gp120 and gp41. In contrast, the monomeric form of gp140 shows significant stabilization of the gp120 inner domain imparted by the gp41 region, demonstrating excellent agreement with past mutagenesis studies. Moreover, the gp140 monomers respond to CD4 binding in manner that is consistent with the initial stages of Env activation: CD4 binding induces structural ordering throughout gp120 while loosening its association with gp41. The results indicate that uncleaved gp140 oligomers do not represent an authentic prefusion form of Env, whereas gp140 monomers isolated from the same glycoprotein preparations in many ways exhibit function and internal structural order that are consistent with expectations for certain aspects of native Env. gp140 monomers may thus be a useful reagent for advancing structural and functional studies.
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Affiliation(s)
- Miklos Guttman
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, USA
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Stabilizing exposure of conserved epitopes by structure guided insertion of disulfide bond in HIV-1 envelope glycoprotein. PLoS One 2013; 8:e76139. [PMID: 24146829 PMCID: PMC3797752 DOI: 10.1371/journal.pone.0076139] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 08/26/2013] [Indexed: 11/19/2022] Open
Abstract
Entry of HIV-1 into target cells requires binding of the viral envelope glycoprotein (Env) to cellular receptors and subsequent conformational changes that culminates in fusion of viral and target cell membranes. Recent structural information has revealed that these conformational transitions are regulated by three conserved but potentially flexible layers stacked between the receptor-binding domain (gp120) and the fusion arm (gp41) of Env. We hypothesized that artificial insertion of a covalent bond will ‘snap’ Env into a conformation that is less mobile and stably expose conserved sites. Therefore, we analyzed the interface between these gp120 layers (layers 1, 2 and 3) and identified residues that may form disulfide bonds when substituted with cysteines. We subsequently probed the structures of the resultant mutant gp120 proteins by assaying their binding to a variety of ligands using Surface Plasmon Resonance (SPR) assay. We found that a single disulfide bond strategically inserted between the highly conserved layers 1 and 2 (C65-C115) is able to ‘lock’ gp120 in a CD4 receptor bound conformation (in the absence of CD4), as indicated by the lower dissociation constant (Kd) for the CD4-induced (CD4i) epitope binding 17b antibody. When disulfide-stabilized monomeric (gp120) and trimeric (gp140) Envs were used to immunize rabbits, they were found to elicit a higher proportion of antibodies directed against both CD4i and CD4 binding site epitopes than the wild-type proteins. These results demonstrate that structure-guided stabilization of inter-layer interactions within HIV-1 Env can be used to expose conserved epitopes and potentially overcome the sequence diversity of these molecules.
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43
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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.
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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
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44
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Molecular architecture of the uncleaved HIV-1 envelope glycoprotein trimer. Proc Natl Acad Sci U S A 2013; 110:12438-43. [PMID: 23757493 DOI: 10.1073/pnas.1307382110] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) trimer, a membrane-fusing machine, mediates virus entry into host cells and is the sole virus-specific target for neutralizing antibodies. Binding the receptors, CD4 and CCR5/CXCR4, triggers Env conformational changes from the metastable unliganded state to the fusion-active state. We used cryo-electron microscopy to obtain a 6-Å structure of the membrane-bound, heavily glycosylated HIV-1 Env trimer in its uncleaved and unliganded state. The spatial organization of secondary structure elements reveals that the unliganded conformations of both glycoprotein (gp)120 and gp41 subunits differ from those induced by receptor binding. The gp120 trimer association domains, which contribute to interprotomer contacts in the unliganded Env trimer, undergo rearrangement upon CD4 binding. In the unliganded Env, intersubunit interactions maintain the gp41 ectodomain helical bundles in a "spring-loaded" conformation distinct from the extended helical coils of the fusion-active state. Quaternary structure regulates the virus-neutralizing potency of antibodies targeting the conserved CD4-binding site on gp120. The Env trimer architecture provides mechanistic insights into the metastability of the unliganded state, receptor-induced conformational changes, and quaternary structure-based strategies for immune evasion.
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45
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Abstract
HIV-1 entry involves the viral envelope glycoproteins (Env gps) and receptors on the target cell. Receptor binding channels the intrinsic high potential energy of Env into the force required to fuse the membranes of virus and target cell. For some HIV-1 strains, prolonged incubation on ice decreases Env potential energy and results in functional inactivation. By characterizing chimeras between two primary clade C HIV-1 strains that differ in sensitivities to cold, soluble CD4, and neutralizing antibodies, we found that these properties were largely determined by discrete elements within the gp120 variable regions V1V2 and V3.
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