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Antibody-Dependent Cellular Cytotoxicity-Competent Antibodies against HIV-1-Infected Cells in Plasma from HIV-Infected Subjects. mBio 2019; 10:mBio.02690-19. [PMID: 31848282 PMCID: PMC6918083 DOI: 10.1128/mbio.02690-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Measuring Envelope (Env)-specific antibody (Ab)-dependent cellular cytotoxicity (ADCC)-competent Abs in HIV+ plasma is challenging because Env displays distinctive epitopes when present in a native closed trimeric conformation on infected cells or in a CD4-bound conformation on uninfected bystander cells. We developed an ADCC model which distinguishes Env-specific ADCC-competent Abs based on their capacity to eliminate infected, bystander, or Env rgp120-coated cells as a surrogate for shed gp120 on bystander cells. A panel of monoclonal Abs (MAbs), used to opsonize these target cells, showed that infected cells were preferentially recognized/eliminated by MAbs to CD4 binding site, V3 loop, and viral spike epitopes whereas bystander/coated cells were preferentially recognized/eliminated by Abs to CD4-induced (CD4i) epitopes. In HIV-positive (HIV+) plasma, Env-specific Abs recognized and supported ADCC of infected cells, though a majority were directed toward CD4i epitopes on bystander cells. For ADCC activity to be effective in HIV control, ADCC-competent Abs need to target genuinely infected cells.IMPORTANCE HIV Env-specific nonneutralizing Abs (NnAbs) able to mediate ADCC have been implicated in protection from HIV infection. However, Env-specific NnAbs have the capacity to support ADCC of both HIV-infected and HIV-uninfected bystander cells, potentially leading to misinterpretations when the assay used to measure ADCC does not distinguish between the two target cell types present in HIV cultures. Using a novel ADCC assay, which simultaneously quantifies the killing activity of Env-specific Abs on both infected and uninfected bystander cells, we observed that only a minority of Env-specific Abs in HIV+ plasma mediated ADCC of genuinely HIV-infected cells displaying Env in its native closed conformation. This assay can be used for the development of vaccine strategies aimed at eliciting Env-specific Ab responses capable of controlling HIV infection.
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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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53
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Yuan C, Wang JY, Zhao HJ, Li Y, Li D, Ling H, Zhuang M. Mutations of Glu560 within HIV-1 Envelope Glycoprotein N-terminal heptad repeat region contribute to resistance to peptide inhibitors of virus entry. Retrovirology 2019; 16:36. [PMID: 31796053 PMCID: PMC6889725 DOI: 10.1186/s12977-019-0496-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 11/21/2019] [Indexed: 11/17/2022] Open
Abstract
Background Peptides corresponding to N- and C-terminal heptad repeat regions (HR1 and HR2, respectively) of gp41 can inhibit HIV-1 infection in a dominant negative manner by interfering with refolding of the viral HR1 and HR2 to form a six-helix bundle (6HB) that induces fusion between viral and host cell membranes. Previously, we found that HIV-1 acquired the mutations of Glu560 (E560) in HR1 of envelope (Env) to escape peptide inhibitors. The present study aimed to elucidate the critical role of position 560 in the virus entry and potential resistance mechanisms. Results The Glu560Lys/Asp/Gly (E560K/D/G) mutations in HR1 of gp41 that are selected under the pressure of N- and C-peptide inhibitors modified its molecular interactions with HR2 to change 6HB stability and peptide inhibitor binding. E560K mutation increased 6HB thermostability and resulted in resistance to N peptide inhibitors, but E560G or E560D as compensatory mutations destabilized the 6HB to reduce inhibitor binding and resulted in increased resistance to C peptide inhibitor, T20. Significantly, the neutralizing activities of all mutants to soluble CD4 and broadly neutralizing antibodies targeting membrane proximal external region, 2F5 and 4E10 were improved, indicating the mutations of E560 could regulate Env conformations through cross interactions with gp120 or gp41. The molecular modeling analysis of E560K/D/G mutants suggested that position 560 might interact with the residues within two potentially flexible topological layer 1 and layer 2 in the gp120 inner domain to apparently affect the CD4 utilization. The E560K/D/G mutations changed its interactions with Gln650 (Q650) in HR2 to contribute to the resistance of peptide inhibitors. Conclusions These findings identify the contributions of mutations of E560K/D/G in the highly conserved gp41 and highlight Env’s high degree of plasticity for virus entry and inhibitor design.
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Affiliation(s)
- Chen Yuan
- Department of Microbiology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Jia-Ye Wang
- Department of Microbiology, Harbin Medical University, Harbin, Heilongjiang, China.,Heilongjiang Provincial Key Laboratory of Infection and Immunity, Harbin, China
| | - Hai-Jiao Zhao
- Department of Microbiology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Yan Li
- Department of Microbiology, Harbin Medical University, Harbin, Heilongjiang, China.,Heilongjiang Provincial Key Laboratory of Infection and Immunity, Harbin, China.,Key Laboratory of Pathogen Biology, Harbin, China
| | - Di Li
- Department of Microbiology, Harbin Medical University, Harbin, Heilongjiang, China.,Heilongjiang Provincial Key Laboratory of Infection and Immunity, Harbin, China.,Key Laboratory of Pathogen Biology, Harbin, China
| | - Hong Ling
- Department of Microbiology, Harbin Medical University, Harbin, Heilongjiang, China. .,Heilongjiang Provincial Key Laboratory of Infection and Immunity, Harbin, China. .,Key Laboratory of Pathogen Biology, Harbin, China. .,Wu Lien-Teh Institute, Harbin Medical University, Harbin, China.
| | - Min Zhuang
- Department of Microbiology, Harbin Medical University, Harbin, Heilongjiang, China. .,Heilongjiang Provincial Key Laboratory of Infection and Immunity, Harbin, China. .,Key Laboratory of Pathogen Biology, Harbin, China. .,Wu Lien-Teh Institute, Harbin Medical University, Harbin, China.
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54
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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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Suttisintong K, Kaewchangwat N, Thanayupong E, Nerungsi C, Srikun O, Pungpo P. Recent Progress in the Development of HIV-1 Entry Inhibitors: From Small Molecules to Potent Anti-HIV Agents. Curr Top Med Chem 2019; 19:1599-1620. [DOI: 10.2174/1568026619666190712204050] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 06/07/2019] [Accepted: 06/21/2019] [Indexed: 01/21/2023]
Abstract
Viral entry, the first process in the reproduction of viruses, primarily involves attachment of the viral envelope proteins to membranes of the host cell. The crucial components that play an important role in viral entry include viral surface glycoprotein gp120, viral transmembrane glycoprotein gp41, host cell glycoprotein (CD4), and host cell chemokine receptors (CCR5 and CXCR4). Inhibition of the multiple molecular interactions of these components can restrain viruses, such as HIV-1, from fusion with the host cell, blocking them from reproducing. This review article specifically focuses on the recent progress in the development of small-molecule HIV-1 entry inhibitors and incorporates important aspects of their structural modification that lead to the discovery of new molecular scaffolds with more potency.
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Affiliation(s)
- Khomson Suttisintong
- National Nanotechnology Center (NANOTEC), National Science and Technology, Development Agency (NSTDA), 111 Thailand Science Park, Phahonyothin Road, Khlong Nueng, Khlong Luang, Pathum Thani 12120, Thailand
| | - Narongpol Kaewchangwat
- National Nanotechnology Center (NANOTEC), National Science and Technology, Development Agency (NSTDA), 111 Thailand Science Park, Phahonyothin Road, Khlong Nueng, Khlong Luang, Pathum Thani 12120, Thailand
| | - Eknarin Thanayupong
- National Nanotechnology Center (NANOTEC), National Science and Technology, Development Agency (NSTDA), 111 Thailand Science Park, Phahonyothin Road, Khlong Nueng, Khlong Luang, Pathum Thani 12120, Thailand
| | - Chakkrapan Nerungsi
- The Government Pharmaceutical Organization, 75/1 Rama VI Road, Ratchathewi, Bangkok 10400, Thailand
| | - Onsiri Srikun
- The Government Pharmaceutical Organization, 75/1 Rama VI Road, Ratchathewi, Bangkok 10400, Thailand
| | - Pornpan Pungpo
- Department of Chemistry, Faculty of Science, Ubon Ratchathani University, 85 Sathonlamark Road, Warinchamrap, Ubon Ratchathani 34190, Thailand
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56
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Understudied Factors Influencing Fc-Mediated Immune Responses against Viral Infections. Vaccines (Basel) 2019; 7:vaccines7030103. [PMID: 31480293 PMCID: PMC6789852 DOI: 10.3390/vaccines7030103] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 08/27/2019] [Accepted: 08/28/2019] [Indexed: 12/26/2022] Open
Abstract
Antibodies play a crucial role in host defense against viruses, both by preventing infection and by controlling viral replication. Besides their capacity to neutralize viruses, antibodies also exert their antiviral effects by crystallizable fragment (Fc)-mediated effector mechanisms. This involves a bridge between innate and adaptive immune systems, wherein antibodies form immune complexes that drive numerous innate immune effector functions, including antibody-dependent cellular cytotoxicity, antibody-dependent complement-mediated lysis, and antibody-dependent phagocytosis. Here, we review certain mechanisms that modulate these antibody-mediated effector functions against virally infected cells, such as viral glycoprotein shedding, viral glycoprotein internalization, antibody cooperativity, and antibody glycosylation. These mechanisms can either protect viral replication or enhance infected cell clearance. Here we discuss the importance of these understudied factors in modulating Fc-mediated effector functions.
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57
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Pu J, Wang Q, Xu W, Lu L, Jiang S. Development of Protein- and Peptide-Based HIV Entry Inhibitors Targeting gp120 or gp41. Viruses 2019; 11:v11080705. [PMID: 31374953 PMCID: PMC6722851 DOI: 10.3390/v11080705] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 07/26/2019] [Accepted: 07/26/2019] [Indexed: 01/08/2023] Open
Abstract
Application of highly active antiretroviral drugs (ARDs) effectively reduces morbidity and mortality in HIV-infected individuals. However, the emergence of multiple drug-resistant strains has led to the increased failure of ARDs, thus calling for the development of anti-HIV drugs with targets or mechanisms of action different from those of the current ARDs. The first peptide-based HIV entry inhibitor, enfuvirtide, was approved by the U.S. FDA in 2003 for treatment of HIV/AIDS patients who have failed to respond to the current ARDs, which has stimulated the development of several series of protein- and peptide-based HIV entry inhibitors in preclinical and clinical studies. In this review, we highlighted the properties and mechanisms of action for those promising protein- and peptide-based HIV entry inhibitors targeting the HIV-1 gp120 or gp41 and discussed their advantages and disadvantages, compared with the current ARDs.
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Affiliation(s)
- Jing Pu
- Shanghai Public Health Clinical Center and School of Basic Medical Sciences, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Fudan University, Shanghai 200032, China
| | - Qian Wang
- Shanghai Public Health Clinical Center and School of Basic Medical Sciences, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Fudan University, Shanghai 200032, China
| | - Wei Xu
- Shanghai Public Health Clinical Center and School of Basic Medical Sciences, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Fudan University, Shanghai 200032, China
| | - Lu Lu
- Shanghai Public Health Clinical Center and School of Basic Medical Sciences, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Fudan University, Shanghai 200032, China.
| | - Shibo Jiang
- Shanghai Public Health Clinical Center and School of Basic Medical Sciences, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Fudan University, Shanghai 200032, China.
- Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10065, USA.
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Effects of the SOS (A501C/T605C) and DS (I201C/A433C) Disulfide Bonds on HIV-1 Membrane Envelope Glycoprotein Conformation and Function. J Virol 2019; 93:JVI.00304-19. [PMID: 30944182 DOI: 10.1128/jvi.00304-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 03/29/2019] [Indexed: 02/06/2023] Open
Abstract
Most broadly neutralizing antibodies and many entry inhibitors target the pretriggered (state 1) conformation of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env). Here we examine two previously reported Env mutants designed to be stabilized in this conformation by the introduction of artificial disulfide bonds: A501C/T605C (called SOS) and I201C/A433C (called DS). SOS Env supported virus entry and cell-cell fusion only after exposure to a reducing agent, dithiothreitol (DTT). Deletion of the Env cytoplasmic tail improved the efficiency with which the SOS Env supported virus infection in a reducing environment. The antigenicity of the SOS Env was similar to that of the unmodified Env, except for greater sensitivity to some state 1-preferring ligands. In contrast, viruses with the DS Env were not infectious, even after DTT treatment. The proteolytic maturation of the DS Env on both cell surfaces and virions was severely compromised compared with that of the unmodified Env. The DS Env exhibited detectable cell-fusing activity when DTT was present. However, the profiles of cell-surface Env recognition and cell-cell fusion inhibition by antibodies differed for the DS Env and the unmodified Env. Thus, the DS Env appears to be stabilized in an off-pathway conformation that is nonfunctional on the virus. The SOS change exerted more subtle, context-dependent effects on Env conformation and function.IMPORTANCE The human immunodeficiency virus type 1 (HIV-1) envelope proteins (Envs) bind receptors on the host cell and change shape to allow the virus to enter the cell. Most virus-inhibiting antibodies and drugs recognize a particular shape of Env called state 1. Disulfide bonds formed by cysteine residues have been introduced into soluble forms of the flexible envelope proteins in an attempt to lock them into state 1 for use in vaccines and as research tools. We evaluated the effect of these cysteine substitutions on the ability of the membrane Env to support virus entry and on susceptibility to inhibition by antibodies and small molecules. We found that the conformation of the envelope proteins with the cysteine substitutions differed from that of the unmodified membrane envelope proteins. Awareness of these effects can assist efforts to create stable HIV-1 Env complexes that more closely resemble the state 1 conformation.
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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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Mutations in the HIV-1 envelope glycoprotein can broadly rescue blocks at multiple steps in the virus replication cycle. Proc Natl Acad Sci U S A 2019; 116:9040-9049. [PMID: 30975760 DOI: 10.1073/pnas.1820333116] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The p6 domain of HIV-1 Gag contains highly conserved peptide motifs that recruit host machinery to sites of virus assembly, thereby promoting particle release from the infected cell. We previously reported that mutations in the YPXnL motif of p6, which binds the host protein Alix, severely impair HIV-1 replication. Propagation of the p6-Alix binding site mutants in the Jurkat T cell line led to the emergence of viral revertants containing compensatory mutations not in Gag but in Vpu and the envelope (Env) glycoprotein subunits gp120 and gp41. The Env compensatory mutants replicate in Jurkat T cells and primary human peripheral blood mononuclear cells, despite exhibiting severe defects in cell-free particle infectivity and Env-mediated fusogenicity. Remarkably, the Env compensatory mutants can also rescue a replication-delayed integrase (IN) mutant, and exhibit reduced sensitivity to the IN inhibitor Dolutegravir (DTG), demonstrating that they confer a global replication advantage. In addition, confirming the ability of Env mutants to confer escape from DTG, we performed de novo selection for DTG resistance and observed resistance mutations in Env. These results identify amino acid substitutions in Env that confer broad escape from defects in virus replication imposed by either mutations in the HIV-1 genome or by an antiretroviral inhibitor. We attribute this phenotype to the ability of the Env mutants to mediate highly efficient cell-to-cell transmission, resulting in an increase in the multiplicity of infection. These findings have broad implications for our understanding of Env function and the evolution of HIV-1 drug resistance.
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61
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Alsahafi N, Bakouche N, Kazemi M, Richard J, Ding S, Bhattacharyya S, Das D, Anand SP, Prévost J, Tolbert WD, Lu H, Medjahed H, Gendron-Lepage G, Ortega Delgado GG, Kirk S, Melillo B, Mothes W, Sodroski J, Smith AB, Kaufmann DE, Wu X, Pazgier M, Rouiller I, Finzi A, Munro JB. An Asymmetric Opening of HIV-1 Envelope Mediates Antibody-Dependent Cellular Cytotoxicity. Cell Host Microbe 2019; 25:578-587.e5. [PMID: 30974085 PMCID: PMC6592637 DOI: 10.1016/j.chom.2019.03.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 12/03/2018] [Accepted: 02/28/2019] [Indexed: 10/27/2022]
Abstract
The HIV-1 envelope glycoprotein (Env) (gp120-gp41)3 is the target for neutralizing antibodies and antibody-dependent cellular cytotoxicity (ADCC). HIV-1 Env is flexible, sampling different conformational states. Before engaging CD4, Env adopts a closed conformation (State 1) that is largely antibody resistant. CD4 binding induces an intermediate state (State 2), followed by an open conformation (State 3) that is susceptible to engagement by antibodies that recognize otherwise occluded epitopes. We investigate conformational changes in Env that induce ADCC in the presence of a small-molecule CD4-mimetic compound (CD4mc). We uncover an asymmetric Env conformation (State 2A) recognized by antibodies targeting the conserved gp120 inner domain and mediating ADCC. Sera from HIV+ individuals contain these antibodies, which can stabilize Env State 2A in combination with CD4mc. Additionally, triggering State 2A on HIV-infected primary CD4+ T cells exposes epitopes that induce ADCC. Strategies that induce this Env conformation may represent approaches to fight HIV-1 infection.
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Affiliation(s)
- Nirmin Alsahafi
- Centre de Recherche du CHUM, Montreal, QC, Canada; Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Nordine Bakouche
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA
| | - Mohsen Kazemi
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia
| | - Jonathan Richard
- Centre de Recherche du CHUM, Montreal, QC, Canada; Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
| | - Shilei Ding
- Centre de Recherche du CHUM, Montreal, QC, Canada; Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
| | - Sudipta Bhattacharyya
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia
| | - Durba Das
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia
| | - Sai Priya Anand
- Centre de Recherche du CHUM, Montreal, QC, Canada; Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, QC, Canada; Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
| | - William D Tolbert
- Infectious Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Hong Lu
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, NY, USA
| | | | | | | | - Sharon Kirk
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Bruno Melillo
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA; Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Amos B Smith
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Daniel E Kaufmann
- Centre de Recherche du CHUM, Montreal, QC, Canada; Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada; Department of Medicine, Université de Montréal, Montreal, QC, Canada; Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Xueling Wu
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, NY, USA
| | - Marzena Pazgier
- Infectious Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Isabelle Rouiller
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia.
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, QC, Canada; Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada; Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada.
| | - James B Munro
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA.
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The Polar Region of the HIV-1 Envelope Protein Determines Viral Fusion and Infectivity by Stabilizing the gp120-gp41 Association. J Virol 2019; 93:JVI.02128-18. [PMID: 30651369 DOI: 10.1128/jvi.02128-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 01/12/2019] [Indexed: 02/06/2023] Open
Abstract
HIV-1 enters cells through binding between viral envelope glycoprotein (Env) and cellular receptors to initiate virus and cell fusion. HIV-1 Env precursor (gp160) is cleaved into two units noncovalently bound to form a trimer on virions, including a surface unit (gp120) and a transmembrane unit (gp41) responsible for virus binding and membrane fusion, respectively. The polar region (PR) at the N terminus of gp41 comprises 17 residues, including 7 polar amino acids. Previous studies suggested that the PR contributes to HIV-1 membrane fusion and infectivity; however, the precise role of the PR in Env-mediated viral entry and the underlying mechanisms remain unknown. Here, we show that the PR is critical for HIV-1 fusion and infectivity by stabilizing Env trimers. Through analyzing the PR sequences of 57,645 HIV-1 isolates, we performed targeted mutagenesis and functional studies of three highly conserved polar residues in the PR (S532P, T534A, and T536A) which have not been characterized previously. We found that single or combined mutations of these three residues abolished or significantly decreased HIV-1 infectivity without affecting viral production. These PR mutations abolished or significantly reduced HIV-1 fusion with target cells and also Env-mediated cell-cell fusion. Three PR mutations containing S532P substantially reduced gp120 and gp41 association, Env trimer stability, and increased gp120 shedding. Furthermore, S532A mutation significantly reduced HIV-1 infectivity and fusogenicity but not Env expression and cleavage. Our findings suggest that the PR of gp41, particularly the key residue S532, is structurally essential for maintaining HIV-1 Env trimer, viral fusogenicity, and infectivity.IMPORTANCE Although extensive studies of the transmembrane unit (gp41) of HIV-1 Env have led to a fusion inhibitor clinically used to block viral entry, the functions of different domains of gp41 in HIV-1 fusion and infectivity are not fully elucidated. The polar region (PR) of gp41 has been proposed to participate in HIV-1 membrane fusion in biochemical analyses, but its role in viral entry and infectivity remain unclear. In our effort to characterize three nucleotide mutations of an HIV-1 RNA element that partially overlaps the PR coding sequence, we identified a novel function of the PR that determines viral fusion and infectivity. We further demonstrated the structural and functional impact of six PR mutations on HIV-1 Env stability, viral fusion, and infectivity. Our findings reveal the previously unappreciated function of the PR and the underlying mechanisms, highlighting the important role of the PR in regulating HIV-1 fusion and infectivity.
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63
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Klug YA, Schwarzer R, Rotem E, Charni M, Nudelman A, Gramatica A, Zarmi B, Rotter V, Shai Y. The HIV gp41 Fusion Protein Inhibits T-Cell Activation through the Lentiviral Lytic Peptide 2 Motif. Biochemistry 2019; 58:818-832. [PMID: 30602116 DOI: 10.1021/acs.biochem.8b01175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The human immunodeficiency virus enters its host cells by membrane fusion, initiated by the gp41 subunit of its envelope protein. gp41 has also been shown to bind T-cell receptor (TCR) complex components, interfering with TCR signaling leading to reduced T-cell activation. This immunoinhibitory activity is suggested to occur during the membrane fusion process and is attributed to various membranotropic regions of the gp41 ectodomain and to the transmembrane domain. Although extensively studied, the cytosolic region of gp41, termed the cytoplasmic tail (CT), has not been examined in the context of immune suppression. Here we investigated whether the CT inhibits T-cell activation in different T-cell models by utilizing gp41-derived peptides and expressed full gp41 proteins. We found that a conserved region of the CT, termed lentiviral lytic peptide 2 (LLP2), specifically inhibits the activation of mouse, Jurkat, and human primary T-cells. This inhibition resulted in reduced T-cell proliferation, gene expression, cytokine secretion, and cell surface expression of CD69. Differential activation of the TCR signaling cascade revealed that CT-based immune suppression occurs downstream of the TCR complex. Moreover, LLP2 peptide treatment of Jurkat and primary human T-cells impaired Akt but not NFκB and ERK1/2 activation, suggesting that immune suppression occurs through the Akt pathway. These findings identify a novel gp41 T-cell suppressive element with a unique inhibitory mechanism that can take place post-membrane fusion.
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Affiliation(s)
- Yoel A Klug
- Department of Biomolecular Sciences , Weizmann Institute of Science , Rehovot 7610001 , Israel
| | - Roland Schwarzer
- Gladstone Institute for Virology and Immunology , University of California, San Francisco , San Francisco , California 94158 , United States
| | - Etai Rotem
- Department of Biomolecular Sciences , Weizmann Institute of Science , Rehovot 7610001 , Israel
| | - Meital Charni
- Department of Molecular Cell Biology , Weizmann Institute of Science , Rehovot 7610001 , Israel
| | - Alon Nudelman
- Department of Biomolecular Sciences , Weizmann Institute of Science , Rehovot 7610001 , Israel
| | - Andrea Gramatica
- Gladstone Institute for Virology and Immunology , University of California, San Francisco , San Francisco , California 94158 , United States
| | - Batya Zarmi
- Department of Biomolecular Sciences , Weizmann Institute of Science , Rehovot 7610001 , Israel
| | - Varda Rotter
- Department of Molecular Cell Biology , Weizmann Institute of Science , Rehovot 7610001 , Israel
| | - Yechiel Shai
- Department of Biomolecular Sciences , Weizmann Institute of Science , Rehovot 7610001 , Israel
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64
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Anand SP, Prévost J, Baril S, Richard J, Medjahed H, Chapleau JP, Tolbert WD, Kirk S, Smith AB, Wines BD, Kent SJ, Hogarth PM, Parsons MS, Pazgier M, Finzi A. Two Families of Env Antibodies Efficiently Engage Fc-Gamma Receptors and Eliminate HIV-1-Infected Cells. J Virol 2019; 93:e01823-18. [PMID: 30429344 PMCID: PMC6340017 DOI: 10.1128/jvi.01823-18] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 11/07/2018] [Indexed: 12/17/2022] Open
Abstract
HIV-1 conceals epitopes of its envelope glycoproteins (Env) recognized by antibody (Ab)-dependent cellular cytotoxicity (ADCC)-mediating antibodies. These Abs, including anti-coreceptor binding site (CoRBS) and anti-cluster A antibodies, preferentially recognize Env in its "open" conformation. The binding of anti-CoRBS Abs has been shown to induce conformational changes that further open Env, allowing interaction of anti-cluster A antibodies. We explored the possibility that CoRBS Abs synergize with anti-cluster A Abs to engage Fc-gamma receptors to mediate ADCC. We found that binding of anti-CoRBS and anti-cluster A Abs to the same gp120 is required for interaction with soluble dimeric FcγRIIIa in enzyme-linked immunosorbent assays (ELISAs). We also found that Fc regions of both Abs are required to optimally engage FcγRIIIa and mediate robust ADCC. Taken together, our results indicate that these two families of Abs act together in a sequential and synergistic fashion to promote FcγRIIIa engagement and ADCC.IMPORTANCE The "open" CD4-bound conformation of HIV-1 envelope glycoproteins is the primary target of antibody-dependent cellular cytotoxicity (ADCC)-mediating antibodies present in HIV-positive (HIV+) sera, such as anti-coreceptor binding site and anti-cluster A antibodies. Here we report that the binding of these two families of antibodies is required to engage FcγRIIIa and mediate ADCC.
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Affiliation(s)
- Sai Priya Anand
- Centre de Recherche du CHUM, Montreal, QC, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, QC, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
| | - Sophie Baril
- Centre de Recherche du CHUM, Montreal, QC, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
| | - Jonathan Richard
- Centre de Recherche du CHUM, Montreal, QC, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
| | | | - Jean-Philippe Chapleau
- Centre de Recherche du CHUM, Montreal, QC, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
| | - William D Tolbert
- Infectious Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Sharon Kirk
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Amos B Smith
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Bruce D Wines
- Immune Therapies Group Burnet Institute, Melbourne, Victoria, Australia
- Department of Clinical Pathology, University of Melbourne, Melbourne, Victoria, Australia
- Department of Immunology and Pathology, Monash University, Melbourne, Victoria, Australia
| | - Stephen J Kent
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - P Mark Hogarth
- Immune Therapies Group Burnet Institute, Melbourne, Victoria, Australia
- Department of Clinical Pathology, University of Melbourne, Melbourne, Victoria, Australia
- Department of Immunology and Pathology, Monash University, Melbourne, Victoria, Australia
| | - Matthew S Parsons
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Marzena Pazgier
- Infectious Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, QC, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
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65
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Tolbert WD, Sherburn RT, Van V, Pazgier M. Structural Basis for Epitopes in the gp120 Cluster A Region that Invokes Potent Effector Cell Activity. Viruses 2019; 11:v11010069. [PMID: 30654465 PMCID: PMC6357199 DOI: 10.3390/v11010069] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/08/2019] [Accepted: 01/10/2019] [Indexed: 12/28/2022] Open
Abstract
While a number of therapeutic options to control the progression of human immunodeficiency virus (HIV-1) now exist, a broadly effective preventive vaccine is still not available. Through detailed structural analysis of antibodies able to induce potent effector cell activity, a number of Env epitopes have been identified which have the potential to be considered vaccine candidates. These antibodies mainly target the gp120 Cluster A region which is only exposed upon viral binding to the target cell with epitopes becoming available for antibody binding during viral entry and fusion and, therefore, after the effective window for neutralizing antibody activity. This review will discuss recent advances in the structural characterization of these important targets with a special focus on epitopes that are involved in Fc-mediated effector function without direct viral neutralizing activities.
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Affiliation(s)
- William D Tolbert
- Infectious Diseases Division, Department of Medicine of Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
| | - Rebekah T Sherburn
- Infectious Diseases Division, Department of Medicine of Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
| | - Verna Van
- Department of Biochemistry and Molecular Biology of University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Marzena Pazgier
- Infectious Diseases Division, Department of Medicine of Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
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66
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Torrents de la Peña A, Sanders RW. Stabilizing HIV-1 envelope glycoprotein trimers to induce neutralizing antibodies. Retrovirology 2018; 15:63. [PMID: 30208933 PMCID: PMC6134781 DOI: 10.1186/s12977-018-0445-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 09/05/2018] [Indexed: 01/03/2023] Open
Abstract
An effective HIV-1 vaccine probably will need to be able to induce broadly neutralizing HIV-1 antibodies (bNAbs) in order to be efficacious. The many bNAbs that have been isolated from HIV-1 infected patients illustrate that the human immune system is able to elicit this type of antibodies. The elucidation of the structure of the HIV-1 envelope glycoprotein (Env) trimer has further fueled the search for Env immunogens that induce bNAbs, but while native Env trimer mimetics are often capable of inducing strain-specific neutralizing antibodies (NAbs) against the parental virus, they have not yet induced potent bNAb responses. To improve the performance of Env trimer immunogens, researchers have studied the immune responses that Env trimers have induced in animals; they have evaluated how to best use Env trimers in various immunization regimens; and they have engineered increasingly stabilized Env trimer variants. Here, we review the different approaches that have been used to increase the stability of HIV-1 Env trimer immunogens with the aim of improving the induction of NAbs. In particular, we draw parallels between the various approaches to stabilize Env trimers and ones that have been used by nature in extremophile microorganisms in order to survive in extreme environmental conditions.
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Affiliation(s)
- Alba Torrents de la Peña
- Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Rogier W. Sanders
- Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY 10021 USA
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67
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Flemming J, Wiesen L, Herschhorn A. Conformation-Dependent Interactions Between HIV-1 Envelope Glycoproteins and Broadly Neutralizing Antibodies. AIDS Res Hum Retroviruses 2018; 34:794-803. [PMID: 29905080 DOI: 10.1089/aid.2018.0102] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
HIV type 1 (HIV-1) envelope glycoproteins (Env) mediate virus entry and are the target of neutralizing antibodies. Binding of the metastable HIV-1 Env trimer to the CD4 receptor triggers structural rearrangements that mediate Env conformational transitions from a closed conformation to a more open state through an intermediate step. Recent studies have revealed new insights on the dynamics, regulation, and molecular mechanisms of Env transitions along the entry pathway. In this study, we provide an overview of the current knowledge on Env conformational dynamics and the relationship between Env conformational states and neutralization selectivity of the broadly neutralizing antibodies that develop in 10%-20% of infected individuals and may provide guidance for the development of an effective HIV-1 vaccine.
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Affiliation(s)
- Juliana Flemming
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Lisa Wiesen
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Alon Herschhorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
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68
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HIV-1 gp41 Residues Modulate CD4-Induced Conformational Changes in the Envelope Glycoprotein and Evolution of a Relaxed Conformation of gp120. J Virol 2018; 92:JVI.00583-18. [PMID: 29875245 DOI: 10.1128/jvi.00583-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 05/24/2018] [Indexed: 01/09/2023] Open
Abstract
Entry of human immunodeficiency virus type 1 (HIV-1) into host cells is mediated by conformational changes in the envelope glycoprotein (Env) that are triggered by Env binding to cellular CD4 and chemokine receptors. These conformational changes involve the opening of the gp120 surface subunit, exposure of the fusion peptide in the gp41 transmembrane subunit, and refolding of the gp41 N- and C-terminal heptad repeat regions (HR1 and HR2) first into an extended prehairpin intermediate and then into a compact 6-helix bundle (6HB) that facilitates fusion between viral and host cell membranes. Previously, we reported that Envs resistant to HR1 peptide fusion inhibitors acquired key resistance mutations in either HR1 or HR2 that increased 6HB stability. Here, we identify residues in HR1 that contribute not only to fusion inhibitor resistance and 6HB stability but also to reduced reactivity to CD4-induced conformational changes that lead to 6HB formation. While all Envs show increased neutralization sensitivity to mimetic CD4 (mCD4), Envs with either the E560K or Q577R HR1 mutation reduced conformational reactivity to CD4 that resisted viral inactivation and triggering to the 6HB. Using a panel of monoclonal antibodies (mAbs), we further determined that Envs from both HR1 and HR2 resistance pathways exhibit a relaxed trimer conformation due to gp120 adaptive mutations in different regions of Env that segregate by resistance pathway. These findings highlight regions of cross talk between gp120 and gp41 and identify HR1 residues that play important roles in regulating CD4-induced conformational changes in Env.IMPORTANCE Binding of the HIV envelope glycoprotein (Env) to cellular CD4 and chemokine receptors triggers conformational changes in Env that mediate virus entry, but premature triggering of Env conformational changes leads to virus inactivation. Currently, we have a limited understanding of the network of residues that regulate Env conformational changes. Here, we identify residues in HR1 of gp41 that modulate conformational changes in response to gp120 binding to CD4 and show that the mutations in HR1 and HR2 that confer resistance to fusion inhibitors are associated with gp120 mutations in different regions of Env that confer a more open conformation. These findings contribute to our understanding of the regulation of Env conformational changes and efforts to design new entry inhibitors and stable Env vaccine immunogens.
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69
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Bowder D, Hollingsead H, Durst K, Hu D, Wei W, Wiggins J, Medjahed H, Finzi A, Sodroski J, Xiang SH. Contribution of the gp120 V3 loop to envelope glycoprotein trimer stability in primate immunodeficiency viruses. Virology 2018; 521:158-168. [PMID: 29936340 PMCID: PMC6053598 DOI: 10.1016/j.virol.2018.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/09/2018] [Accepted: 06/11/2018] [Indexed: 02/06/2023]
Abstract
The V3 loop of the human immunodeficiency virus type 1 (HIV-1) gp120 exterior envelope glycoprotein (Env) becomes exposed after CD4 binding and contacts the coreceptor to mediate viral entry. Prior to CD4 engagement, a hydrophobic patch located at the tip of the V3 loop stabilizes the non-covalent association of gp120 with the Env trimer of HIV-1 subtype B strains. Here, we show that this conserved hydrophobic patch (amino acid residues 307, 309 and 317) contributes to gp120-trimer association in HIV-1 subtype C, HIV-2 and SIV. Changes that reduced the hydrophobicity of these V3 residues resulted in increased gp120 shedding and decreased Env-mediated cell-cell fusion and virus entry in the different primate immunodeficiency viruses tested. Thus, the hydrophobic patch is an evolutionarily conserved element in the tip of the gp120 V3 loop that plays an essential role in maintaining the stability of the pre-triggered Env trimer in diverse primate immunodeficiency viruses. The V3-loop of HIV-1 gp120 contributes to Env trimer stability and viral entry. The hydrophobic patch in the tip of the V3 loop is critical for pre-triggered Env trimer stability. The hydrophobic patch is a conserved motif in primate immunodeficiency viruses.
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Affiliation(s)
- 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
| | - Haley Hollingsead
- 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
| | - Kate Durst
- 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
| | - 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
| | - 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
| | - Joshua Wiggins
- 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
| | - Halima Medjahed
- Centre de Recherche du CHUM, Department of Microbiology, Infectious Diseases and Immunology, Université de Montréal, Montreal, QC, Canada
| | - Andrés Finzi
- Centre de Recherche du CHUM, Department of Microbiology, Infectious Diseases and Immunology, Université de Montréal, Montreal, QC, Canada
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, United States; Department of Microbiology and Immunobiology, Division of AIDS, Harvard Medical School, Boston, MA 02215, United States; Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, 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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70
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Incomplete Downregulation of CD4 Expression Affects HIV-1 Env Conformation and Antibody-Dependent Cellular Cytotoxicity Responses. J Virol 2018; 92:JVI.00484-18. [PMID: 29669829 PMCID: PMC6002730 DOI: 10.1128/jvi.00484-18] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 04/11/2018] [Indexed: 12/13/2022] Open
Abstract
HIV-1-infected cells expressing envelope glycoproteins (Env) in the CD4-bound conformation on their surfaces are targeted by antibody-dependent cellular cytotoxicity (ADCC) mediated by CD4-induced (CD4i) antibodies and sera from HIV-1-infected individuals (HIV+ sera). By downregulating the surface expression of CD4, Nef prevents Env-CD4 interaction, thus protecting HIV-1-infected cells from ADCC. HIV-1 infectious molecular clones (IMCs) are widely used to measure ADCC. In order to facilitate the identification of infected cells and high-throughput ADCC analysis, reporter genes (e.g., the Renilla luciferase [LucR] gene) are often introduced into IMC constructs. We evaluated the susceptibility of HIV-1-infected CD4+ T lymphocytes to ADCC using a panel of parental IMCs and derivatives that expressed the LucR reporter gene, utilizing different molecular strategies, including one specifically designed to retain Nef expression. We found that in some of these constructs, Nef expression in CD4+ T cells was suboptimal, and consequently, CD4 downregulation was incomplete. CD4 molecules remaining on the cell surface resulted in the exposure of ADCC-mediating CD4i epitopes on Env and a dramatic increase in the susceptibility of the infected cells to ADCC. Strikingly, protection from ADCC was observed when cells were infected with the parental IMC, which exhibited strong CD4 downregulation. This discrepancy between the parental and Nef-impaired viruses was independent of the strains of Env expressed, but rather, it was correlated with the levels of CD4 surface expression. Overall, our results indicate that caution should be taken when selecting IMCs for ADCC measurements and that CD4 downregulation needs to be carefully monitored when drawing conclusions about the nature and magnitude of ADCC. IMPORTANCE In-depth understanding of the susceptibility of HIV-1-infected cells to ADCC might help establish correlates of vaccine protection and guide the development of HIV-1 vaccine strategies. Different ADCC assays have been developed, including those using infectious molecular clones (IMCs) carrying a LucR reporter gene that greatly facilitates large-scale quantitative analysis. We previously reported different molecular strategies for introducing LucR while maintaining Nef expression and function and, consequently, CD4 surface downregulation. Here, we demonstrate that utilizing IMCs that exhibit impaired Nef expression can have undesirable consequences due to incomplete CD4 downregulation. CD4 molecules remaining on the cell surface resulted in the exposure of ADCC-mediating CD4i epitopes on Env and a dramatic increase in the susceptibility of the infected cells to ADCC. Overall, our results indicate that CD4 downregulation needs to be carefully monitored when drawing conclusions about the nature and magnitude of ADCC.
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71
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Bowder D, Thompson J, Durst K, Hollingsead H, Hu D, Wei W, Xiang SH. Characterization of twin-cysteine motif in the V2-loop region of gp120 in primate lentiviruses. Virology 2018; 519:180-189. [DOI: 10.1016/j.virol.2018.04.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 04/15/2018] [Accepted: 04/17/2018] [Indexed: 10/17/2022]
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72
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Zhang Y, Guo J, Huang L, Tian J, Yao X, Liu H. The molecular mechanism of two coreceptor binding site antibodies X5 and 17b neutralizing HIV-1: Insights from molecular dynamics simulation. Chem Biol Drug Des 2018; 92:1357-1365. [PMID: 29624884 DOI: 10.1111/cbdd.13201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 03/04/2018] [Accepted: 03/07/2018] [Indexed: 11/28/2022]
Abstract
The coreceptor binding site of gp120 plays an important role in HIV entry into host cell. X5 and 17b are typical coreceptor binding site antibodies with the ability to broadly neutralize HIV. Thus, here, to study the neutralizing mechanism of two antibodies and identify the source of two antibodies with different neutralizing ability, we performed molecular dynamics simulations for the complexes of X5 and 17b with gp120 and CD4. The simulation results indicate X5 and 17b mainly affects CD4 and coreceptor binding sites. Specifically, for CD4 binding site (CD4bs), the binding of antibodies has different effects on CD4bs with and without CD4. However, for coreceptor binding sites, the binding of the antibodies has consistent influence on the region adjacent to loop V3 despite of the simulated systems with or without CD4. The binding of the antibodies enhances the interactions of gp120 region adjacent to loop V3 with other region of gp120, which are unfavorable for conformational rearrangements of the region adjacent to loop V3 and further binding the coreceptor. Additionally, the interactions of loop V3 and bridging sheet with X5 lead to the close motion of loop V3 in X5 bound form, which further influences the rearrangements in gp120.
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Affiliation(s)
- Yan Zhang
- School of Pharmacy, Lanzhou University, Lanzhou, China.,Guiyang College of Traditional Chinese Medicine, Guiyang, China.,State Key Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou, China
| | - Jingjing Guo
- Henan Engineering Research Center of Chiral Hydroxyl Pharmaceutical, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, China
| | - Le Huang
- School of Pharmacy, Lanzhou University, Lanzhou, China
| | - Jiaqi Tian
- School of Pharmacy, Lanzhou University, Lanzhou, China
| | - Xiaojun Yao
- State Key Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou, China
| | - Huanxiang Liu
- School of Pharmacy, Lanzhou University, Lanzhou, China.,State Key Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou, China
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73
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Identification of Near-Pan-neutralizing Antibodies against HIV-1 by Deconvolution of Plasma Humoral Responses. Cell 2018; 173:1783-1795.e14. [PMID: 29731169 DOI: 10.1016/j.cell.2018.03.061] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 03/22/2018] [Accepted: 03/22/2018] [Indexed: 11/20/2022]
Abstract
Anti-HIV-1 envelope broadly neutralizing monoclonal antibodies (bNAbs) isolated from memory B cells may not fully represent HIV-1-neutralizing profiles measured in plasma. Accordingly, we characterized near-pan-neutralizing antibodies extracted directly from the plasma of two "elite neutralizers." Circulating anti-gp120 polyclonal antibodies were deconvoluted using proteomics to guide lineage analysis of bone marrow plasma cells. In both subjects, a single lineage of anti-CD4-binding site (CD4bs) antibodies explained the plasma-neutralizing activity. Importantly, members of these lineages potently neutralized 89%-100% of a multi-tier 117 pseudovirus panel, closely matching the specificity and breadth of the circulating antibodies. X-ray crystallographic analysis of one monoclonal, N49P7, suggested a unique ability to bypass the CD4bs Phe43 cavity, while reaching deep into highly conserved residues of Layer 3 of the gp120 inner domain, likely explaining its extreme potency and breadth. Further direct analyses of plasma anti-HIV-1 bNAbs should provide new insights for developing antibody-based antiviral agents and vaccines.
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74
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Ikeda T, Symeonides M, Albin JS, Li M, Thali M, Harris RS. HIV-1 adaptation studies reveal a novel Env-mediated homeostasis mechanism for evading lethal hypermutation by APOBEC3G. PLoS Pathog 2018; 14:e1007010. [PMID: 29677220 PMCID: PMC5931688 DOI: 10.1371/journal.ppat.1007010] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Revised: 05/02/2018] [Accepted: 04/09/2018] [Indexed: 02/07/2023] Open
Abstract
HIV-1 replication normally requires Vif-mediated neutralization of APOBEC3 antiviral enzymes. Viruses lacking Vif succumb to deamination-dependent and -independent restriction processes. Here, HIV-1 adaptation studies were leveraged to ask whether viruses with an irreparable vif deletion could develop resistance to restrictive levels of APOBEC3G. Several resistant viruses were recovered with multiple amino acid substitutions in Env, and these changes alone are sufficient to protect Vif-null viruses from APOBEC3G-dependent restriction in T cell lines. Env adaptations cause decreased fusogenicity, which results in higher levels of Gag-Pol packaging. Increased concentrations of packaged Pol in turn enable faster virus DNA replication and protection from APOBEC3G-mediated hypermutation of viral replication intermediates. Taken together, these studies reveal that a moderate decrease in one essential viral activity, namely Env-mediated fusogenicity, enables the virus to change other activities, here, Gag-Pol packaging during particle production, and thereby escape restriction by the antiviral factor APOBEC3G. We propose a new paradigm in which alterations in viral homeostasis, through compensatory small changes, constitute a general mechanism used by HIV-1 and other viral pathogens to escape innate antiviral responses and other inhibitions including antiviral drugs.
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Affiliation(s)
- Terumasa Ikeda
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, United States of America
- Howard Hughes Medical Institute, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Menelaos Symeonides
- Cellular, Molecular and Biomedical Sciences Graduate Program and Department of Microbiology and Molecular Genetics, Larner College of Medicine and College of Agriculture and Life Sciences, University of Vermont, Burlington, Vermont, United States of America
| | - John S. Albin
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Ming Li
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Markus Thali
- Cellular, Molecular and Biomedical Sciences Graduate Program and Department of Microbiology and Molecular Genetics, Larner College of Medicine and College of Agriculture and Life Sciences, University of Vermont, Burlington, Vermont, United States of America
| | - Reuben S. Harris
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, United States of America
- Howard Hughes Medical Institute, University of Minnesota, Minneapolis, Minnesota, United States of America
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75
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Uninfected Bystander Cells Impact the Measurement of HIV-Specific Antibody-Dependent Cellular Cytotoxicity Responses. mBio 2018; 9:mBio.00358-18. [PMID: 29559570 PMCID: PMC5874913 DOI: 10.1128/mbio.00358-18] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The conformation of the HIV-1 envelope glycoprotein (Env) substantially impacts antibody recognition and antibody-dependent cellular cytotoxicity (ADCC) responses. In the absence of the CD4 receptor at the cell surface, primary Envs sample a “closed” conformation that occludes CD4-induced (CD4i) epitopes. The virus controls CD4 expression through the actions of Nef and Vpu accessory proteins, thus protecting infected cells from ADCC responses. However, gp120 shed from infected cells can bind to CD4 present on uninfected bystander cells, sensitizing them to ADCC mediated by CD4i antibodies (Abs). Therefore, we hypothesized that these bystander cells could impact the interpretation of ADCC measurements. To investigate this, we evaluated the ability of antibodies to CD4i epitopes and broadly neutralizing Abs (bNAbs) to mediate ADCC measured by five ADCC assays commonly used in the field. Our results indicate that the uninfected bystander cells coated with gp120 are efficiently recognized by the CD4i ligands but not the bNabs. Consequently, the uninfected bystander cells substantially affect in vitro measurements made with ADCC assays that fail to identify responses against infected versus uninfected cells. Moreover, using an mRNA flow technique that detects productively infected cells, we found that the vast majority of HIV-1-infected cells in in vitro cultures or ex vivo samples from HIV-1-infected individuals are CD4 negative and therefore do not expose significant levels of CD4i epitopes. Altogether, our results indicate that ADCC assays unable to differentiate responses against infected versus uninfected cells overestimate responses mediated by CD4i ligands. Emerging evidence supports a role for antibody-dependent cellular cytotoxicity (ADCC) in protection against HIV-1 transmission and disease progression. However, there are conflicting reports regarding the ability of nonneutralizing antibodies targeting CD4-inducible (CD4i) Env epitopes to mediate ADCC. Here, we performed a side-by-side comparison of different methods currently being used in the field to measure ADCC responses to HIV-1. We found that assays which are unable to differentiate virus-infected from uninfected cells greatly overestimate ADCC responses mediated by antibodies to CD4i epitopes and underestimate responses mediated by broadly neutralizing antibodies (bNAbs). Our results strongly argue for the use of assays that measure ADCC against HIV-1-infected cells expressing physiologically relevant conformations of Env to evaluate correlates of protection in vaccine trials.
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76
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Envelope glycoproteins sampling states 2/3 are susceptible to ADCC by sera from HIV-1-infected individuals. Virology 2017; 515:38-45. [PMID: 29248757 DOI: 10.1016/j.virol.2017.12.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/04/2017] [Accepted: 12/05/2017] [Indexed: 12/25/2022]
Abstract
Recent analysis of HIV-1 envelope glycoproteins (Env) dynamics showed that the unliganded Env trimer can potentially sample three conformations: a metastable "closed" conformation (State 1), an "open" CD4-bound conformation (State 3), and an intermediate "partially open" conformation (State 2). HIV-1 evolved several mechanisms to avoid "opening" its Env in order to evade immune responses such as antibody-dependent cellular cytotoxicity (ADCC), which preferentially targets Envs in the CD4-bound conformation on the surface of infected cells. Here we took advantage of a well-characterized single-residue change in the gp120 trimer association domain to modify Env conformation and evaluate its impact on ADCC responses. We found that cells infected with viruses expressing Env stabilized in States 2/3 become highly susceptible to ADCC responses by sera from HIV-1-infected individuals. Our results indicate that the conformations spontaneously sampled by the Env trimer at the surface of infected cells has a significant impact on ADCC responses.
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77
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Functional Stability of HIV-1 Envelope Trimer Affects Accessibility to Broadly Neutralizing Antibodies at Its Apex. J Virol 2017; 91:JVI.01216-17. [PMID: 28978711 DOI: 10.1128/jvi.01216-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 09/29/2017] [Indexed: 02/07/2023] Open
Abstract
The trimeric envelope glycoprotein spike (Env) of HIV-1 is the target of vaccine development to elicit broadly neutralizing antibodies (bnAbs). Env trimer instability and heterogeneity in principle make subunit interfaces inconsistent targets for the immune response. Here, we investigate how functional stability of Env relates to neutralization sensitivity to V2 bnAbs and V3 crown antibodies that engage subunit interfaces upon binding to unliganded Env. Env heterogeneity was inferred when antibodies neutralized a mutant Env with a plateau of less than 100% neutralization. A statistically significant correlation was found between the stability of mutant Envs and the MPN of V2 bnAb, PG9, as well as an inverse correlation between stability of Env and neutralization by V3 crown antibody, 447-52D. A number of Env-stabilizing mutations and V2 bnAb-enhancing mutations were identified in Env, but they did not always overlap, indicating distinct requirements of functional stabilization versus antibody recognition. Blocking complex glycosylation of Env affected V2 bnAb recognition, as previously described, but also notably increased functional stability of Env. This study shows how instability and heterogeneity affect antibody sensitivity of HIV-1 Env, which is relevant to vaccine design involving its dynamic apex.IMPORTANCE The Env trimer is the only viral protein on the surface of HIV-1 and is the target of neutralizing antibodies that reduce viral infectivity. Quaternary epitopes at the apex of the spike are recognized by some of the most potent and broadly neutralizing antibodies to date. Being that their glycan-protein hybrid epitopes are at subunit interfaces, the resulting heterogeneity can lead to partial neutralization. Here, we screened for mutations in Env that allowed for complete neutralization by the bnAbs. We found that when mutations outside V2 increased V2 bnAb recognition, they often also increased Env stability-of-function and decreased binding by narrowly neutralizing antibodies to the V3 crown. Three mutations together increased neutralization by V2 bnAb and eliminated binding by V3 crown antibodies. These results may aid the design of immunogens that elicit antibodies to the trimer apex.
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78
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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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79
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Tolbert WD, Gohain N, Alsahafi N, Van V, Orlandi C, Ding S, Martin L, Finzi A, Lewis GK, Ray K, Pazgier M. Targeting the Late Stage of HIV-1 Entry for Antibody-Dependent Cellular Cytotoxicity: Structural Basis for Env Epitopes in the C11 Region. Structure 2017; 25:1719-1731.e4. [PMID: 29056481 PMCID: PMC5677539 DOI: 10.1016/j.str.2017.09.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/28/2017] [Accepted: 09/18/2017] [Indexed: 01/14/2023]
Abstract
Antibodies can have an impact on HIV-1 infection in multiple ways, including antibody-dependent cellular cytotoxicity (ADCC), a correlate of protection observed in the RV144 vaccine trial. One of the most potent ADCC-inducing epitopes on HIV-1 Env is recognized by the C11 antibody. Here, we present the crystal structure, at 2.9 Å resolution, of the C11-like antibody N12-i3, in a quaternary complex with the HIV-1 gp120, a CD4-mimicking peptide M48U1, and an A32-like antibody, N5-i5. Antibody N12-i3 recognizes an epitope centered on the N-terminal "eighth strand" of a critical β sandwich, which our analysis indicates to be emblematic of a late-entry state, after the gp120 detachment. In prior entry states, this sandwich comprises only seven strands, with the eighth strand instead pairing with a portion of the gp120 C terminus. The conformational gymnastics of HIV-1 gp120 thus includes altered β-strand pairing, possibly to reduce immunogenicity, although nevertheless still recognized by the human immune system.
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Affiliation(s)
- William D. Tolbert
- Division of Vaccine Research, Institute of Human Virology, Biology of University of Maryland School of Medicine, Baltimore, USA,Department of Biochemistry and Molecular, Biology of University of Maryland School of Medicine, Baltimore, USA
| | - Neelakshi Gohain
- Division of Vaccine Research, Institute of Human Virology, Biology of University of Maryland School of Medicine, Baltimore, USA,Department of Biochemistry and Molecular, Biology of University of Maryland School of Medicine, Baltimore, USA
| | - Nirmin Alsahafi
- Centre de Recherche du CHUM, Université de Montréal, Montreal, Quebec, Canada,CEA, Joliot, Service d’Ingénierie Moléculaire des Protéines, F-91191 Gif-sur-Yvette, France
| | - Verna Van
- Division of Vaccine Research, Institute of Human Virology, Biology of University of Maryland School of Medicine, Baltimore, USA,Department of Biochemistry and Molecular, Biology of University of Maryland School of Medicine, Baltimore, USA
| | - Chiara Orlandi
- Division of Vaccine Research, Institute of Human Virology, Biology of University of Maryland School of Medicine, Baltimore, USA,Department of Microbiology and Immunology of University of Maryland School of Medicine, Baltimore, USA
| | - Shilei Ding
- Centre de Recherche du CHUM, Université de Montréal, Montreal, Quebec, Canada,Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, Quebec, Canada
| | - Loïc Martin
- CEA, Joliot, Service d’Ingénierie Moléculaire des Protéines, F-91191 Gif-sur-Yvette, France
| | - 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
| | - George K. Lewis
- Division of Vaccine Research, Institute of Human Virology, Biology of University of Maryland School of Medicine, Baltimore, USA,Department of Microbiology and Immunology of University of Maryland School of Medicine, Baltimore, USA
| | - Krishanu Ray
- Department of Biochemistry and Molecular, Biology of University of Maryland School of Medicine, Baltimore, USA
| | - Marzena Pazgier
- Division of Vaccine Research, Institute of Human Virology, Biology of University of Maryland School of Medicine, Baltimore, USA,Department of Biochemistry and Molecular, Biology of University of Maryland School of Medicine, Baltimore, USA,To whom correspondence should be addressed: , 725 West Lombard Street, Baltimore, MD 21201, USA, Tel: (410) 706-4780, Fax: (410) 706-7583
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80
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Herschhorn A, Gu C, Moraca F, Ma X, Farrell M, Smith AB, Pancera M, Kwong PD, Schön A, Freire E, Abrams C, Blanchard SC, Mothes W, Sodroski JG. The β20-β21 of gp120 is a regulatory switch for HIV-1 Env conformational transitions. Nat Commun 2017; 8:1049. [PMID: 29051495 PMCID: PMC5648922 DOI: 10.1038/s41467-017-01119-w] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 08/18/2017] [Indexed: 11/09/2022] Open
Abstract
The entry of HIV-1 into target cells is mediated by the viral envelope glycoproteins (Env). Binding to the CD4 receptor triggers a cascade of conformational changes in distant domains that move Env from a functionally “closed” State 1 to more “open” conformations, but the molecular mechanisms underlying allosteric regulation of these transitions are still elusive. Here, we develop chemical probes that block CD4-induced conformational changes in Env and use them to identify a potential control switch for Env structural rearrangements. We identify the gp120 β20–β21 element as a major regulator of Env transitions. Several amino acid changes in the β20–β21 base lead to open Env conformations, recapitulating the structural changes induced by CD4 binding. These HIV-1 mutants require less CD4 to infect cells and are relatively resistant to State 1-preferring broadly neutralizing antibodies. These data provide insights into the molecular mechanism and vulnerability of HIV-1 entry. Binding of viral envelope glycoproteins (Env) to the host cell CD4 receptor mediates HIV-1 entry. Here, the authors develop compounds that inhibit the CD4-induced conformational changes in Env and show that the gp120 β20-β21 element is a key regulator for Env transitions.
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Affiliation(s)
- Alon Herschhorn
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, 02215, USA. .,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, 02115, USA.
| | - Christopher Gu
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, 02215, USA
| | - Francesca Moraca
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania, 19104, USA
| | - Xiaochu Ma
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, 06536, USA
| | - Mark Farrell
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, USA
| | - Amos B Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, USA
| | - Marie Pancera
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, 20892, USA
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, 20892, USA
| | - Arne Schön
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, 21218, USA
| | - Ernesto Freire
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, 21218, USA
| | - Cameron Abrams
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania, 19104, USA
| | - Scott C Blanchard
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, New York, 10065, USA
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, 06536, USA
| | - Joseph G Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, 02215, USA. .,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, 02115, USA. .,Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, 02115, USA.
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81
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Racine T, Kobinger GP, Arts EJ. Development of an HIV vaccine using a vesicular stomatitis virus vector expressing designer HIV-1 envelope glycoproteins to enhance humoral responses. AIDS Res Ther 2017; 14:55. [PMID: 28893277 PMCID: PMC5594459 DOI: 10.1186/s12981-017-0179-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 08/22/2017] [Indexed: 11/30/2022] Open
Abstract
Vesicular stomatitis virus (VSV), like many other Rhabdoviruses, have become the focus of intense research over the past couple of decades based on their suitability as vaccine vectors, transient gene delivery systems, and as oncolytic viruses for cancer therapy. VSV as a vaccine vector platform has multiple advantages over more traditional viral vectors including low level, non-pathogenic replication in diverse cell types, ability to induce both humoral and cell-mediate immune responses, and the remarkable expression of foreign proteins cloned into multiple intergenic sites in the VSV genome. The utility and safety of VSV as a vaccine vector was recently demonstrated near the end of the recent Ebola outbreak in West Africa where VSV pseudotyped with the Ebola virus (EBOV) glycoprotein was proven safe in humans and provided protective efficacy against EBOV in a human phase III clinical trial. A team of Canadian scientists, led by Dr. Gary Kobinger, is now working with International AIDS Vaccine Initiative (IAVI) in developing a VSV-based HIV vaccine that will combine unique Canadian research on the HIV-1 Env glycoprotein and on the VSV vaccine vector. The goal of this collaboration is to develop a vaccine with a robust and potent anti-HIV immune response with an emphasis on generating quality antibodies to protect against HIV challenges.
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82
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Lewis GK, Pazgier M, Evans DT, Ferrari G, Bournazos S, Parsons MS, Bernard NF, Finzi A. Beyond Viral Neutralization. AIDS Res Hum Retroviruses 2017; 33:760-764. [PMID: 28084796 PMCID: PMC5695748 DOI: 10.1089/aid.2016.0299] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
It has been known for more than 30 years that HIV-1 infection drives a very potent B cell response resulting in the production of anti-HIV-1 antibodies targeting several viral proteins, particularly its envelope glycoproteins (Env). Env epitopes are exposed on the surfaces of viral particles and infected cells where they are targets of potentially protective antibodies. These antibodies can interdict infection by neutralization and there is strong evidence suggesting that Fc-mediated effector function can also contribute to protection. Current evidence suggests that Fc-mediated effector function plays a role in protection against infection by broadly neutralizing antibodies and it might be important for protection by non-neutralizing antibodies. Fc-mediated effector function includes diverse mechanisms such as antibody-dependent cellular cytotoxicity (ADCC), antibody-mediated complement activation, antibody-dependent cellular phagocytosis, antibody-dependent cell-mediated virus inhibition, antibody-mediated trancytosis inhibition, and antibody-mediated virus opsonization. All these functions could be beneficial in fighting viral infections, including HIV-1. In this perspective, we discuss the latest developments in ADCC research discussed at the HIVR4P satellite session on non-neutralizing antibodies, with emphasis on the mechanisms of ADCC resistance used by HIV-1, the structural basis of epitopes recognized by antibodies that mediate ADCC, natural killer-cell education and ADCC, and murine models to study ADCC against HIV-1.
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Affiliation(s)
- George K. Lewis
- Division of Vaccine Research of Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Marzena Pazgier
- Division of Vaccine Research of Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - David T. Evans
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, Wisconsin
- Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, Wisconsin
| | - Guido Ferrari
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina
| | - Stylianos Bournazos
- Laboratory of Molecular Genetics and Immunology, The Rockefeller University, New York, New York
| | - Matthew S. Parsons
- Department of Microbiology and Immunology, University of Melbourne, Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Nicole F. Bernard
- Research Institute of the McGill University Health Centre, Division of Experimental Medicine, McGill University, Quebec, Canada
| | - Andrés Finzi
- Centre de Recherche du CHUM, Université de Montréal, Quebec, Canada
- Department of Microbiology, Infectiology and Immunology, Université de Montréal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Quebec, Canada
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83
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Ozorowski G, Pallesen J, de Val N, Lyumkis D, Cottrell CA, Torres JL, Copps J, Stanfield RL, Cupo A, Pugach P, Moore JP, Wilson IA, Ward AB. Open and closed structures reveal allostery and pliability in the HIV-1 envelope spike. Nature 2017; 547:360-363. [PMID: 28700571 PMCID: PMC5538736 DOI: 10.1038/nature23010] [Citation(s) in RCA: 182] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 05/22/2017] [Indexed: 12/17/2022]
Abstract
For many enveloped viruses, binding to a receptor(s) on a host cell acts as a first step in a series of events culminating in fusion with the host cell membrane and transfer of genetic material for replication [for review see1,2]. The envelope glycoprotein (Env) trimer on the surface of HIV is responsible for receptor binding and fusion. While Env can tolerate a high degree of mutation in five variable regions (V1-V5), and also at N-linked glycosylation sites that contribute roughly half the mass of Env, the functional sites for recognition of receptor CD4 and co-receptor CXCR4/CCR5 are conserved and essential for viral fitness. Soluble SOSIP Env trimers are structural and antigenic mimics of the pre-fusion native, surface-presented Env3,4, targets of broadly neutralizing antibodies (bnAbs). Thus, they are attractive immunogens for vaccine development [for review see5–8]. Here we present high-resolution cryo-electron microscopy (cryoEM) structures of subtype B B41 SOSIP Env trimers in complex with CD4 and antibody 17b, or with antibody b12, at resolutions of ~3.7 Å and ~3.6 Å, respectively, and compare them to cryoEM reconstructions of ligand-free B41 SOSIP Env trimers or in complex with either CD4 or CD4bs antibody PGV04, at ~5.6 Å, ~5.2 Å and ~7.4 Å, respectively. Consequently, we present the most complete description and understanding of the CD4/17b-induced intermediate and provide the molecular basis of the receptor-binding induced conformational change required for HIV-1 entry into host cells. Both CD4 and b12 induce large, previously uncharacterized conformational rearrangements in the gp41 subunits, and the fusion peptide becomes more buried in a newly formed pocket. These structures provide key details on the biological function of the type I viral fusion machine from HIV-1 as well as new templates for inhibitor design.
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Affiliation(s)
- Gabriel Ozorowski
- Department of Integrative Structural and Computational Biology, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, International AIDS Vaccine Initiative Neutralizing Antibody Center, and Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Jesper Pallesen
- Department of Integrative Structural and Computational Biology, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, International AIDS Vaccine Initiative Neutralizing Antibody Center, and Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Natalia de Val
- Department of Integrative Structural and Computational Biology, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, International AIDS Vaccine Initiative Neutralizing Antibody Center, and Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Dmitry Lyumkis
- Laboratory of Genetics and Helmsley Center for Genomic Medicine, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA
| | - Christopher A Cottrell
- Department of Integrative Structural and Computational Biology, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, International AIDS Vaccine Initiative Neutralizing Antibody Center, and Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Jonathan L Torres
- Department of Integrative Structural and Computational Biology, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, International AIDS Vaccine Initiative Neutralizing Antibody Center, and Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Jeffrey Copps
- Department of Integrative Structural and Computational Biology, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, International AIDS Vaccine Initiative Neutralizing Antibody Center, and Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Robyn L Stanfield
- Department of Integrative Structural and Computational Biology, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, International AIDS Vaccine Initiative Neutralizing Antibody Center, and Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Albert Cupo
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, USA
| | - Pavel Pugach
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, USA
| | - John P Moore
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, USA
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, International AIDS Vaccine Initiative Neutralizing Antibody Center, and Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California 92037, USA.,The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, International AIDS Vaccine Initiative Neutralizing Antibody Center, and Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California 92037, USA
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84
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Herschhorn A, Sodroski J. An entry-competent intermediate state of the HIV-1 envelope glycoproteins. ACTA ACUST UNITED AC 2017; 4. [PMID: 28752105 PMCID: PMC5526225 DOI: 10.14800/rci.1544] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins (Env) mediate viral entry and are the sole target of neutralizing antibodies. Recent studies show that the metastable HIV-1 Env trimer can transit among three conformational states: State 1, State 3, and State 2, corresponding to the “closed”, “open” and intermediate conformations, respectively. During virus entry, binding to the CD4 receptor drives Env from state 1 to state 3. In the unliganded Env, transitions from the closed (State 1) conformation are restrained by intramolecular interactions among different Env residues, which regulate HIV-1 Env conformation. Releasing the specific restraints on State 1 Env leads to increased occupancy of State 2, which is a functional conformation on the entry pathway and an obligate intermediate between State 1 and State 3. Frequent sampling of intermediate State 2 allows HIV-1 to infect cells expressing low levels of CD4, and leads to resistance to several broadly neutralizing antibodies as well as small-molecule inhibitors. Recent findings provide new mechanistic insights into the function and inhibition of HIV-1 Env and will contribute to the development of new therapeutic and prophylactic interventions to combat HIV-1.
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Affiliation(s)
- Alon Herschhorn
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, 02215, MA, USA.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, 02215, MA, USA
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, 02215, MA, USA.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, 02215, MA, USA.,Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, 02215, MA, USA
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85
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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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86
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HIV-1 gp120 envelope glycoprotein determinants for cytokine burst in human monocytes. PLoS One 2017; 12:e0174550. [PMID: 28346521 PMCID: PMC5367833 DOI: 10.1371/journal.pone.0174550] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 03/10/2017] [Indexed: 11/26/2022] Open
Abstract
The first step of HIV infection involves the interaction of the gp120 envelope glycoprotein to its receptor CD4, mainly expressed on CD4+ T cells. Besides its role on HIV-1 entry, the gp120 has been shown to be involved in the production of IL-1, IL-6, CCL20 and other innate response cytokines by bystander, uninfected CD4+ T cells and monocytes. However, the gp120 determinants involved in these functions are not completely understood. Whether signalling leading to cytokine production is due to CD4 or other receptors is still unclear. Enhanced chemokine receptor binding and subsequent clustering receptors may lead to cytokine production. By using a comprehensive panel of gp120 mutants, here we show that CD4 binding is mandatory for cytokine outburst in monocytes. Our data suggest that targeting monocytes in HIV-infected patients might decrease systemic inflammation and the potential tissue injury associated with the production of inflammatory cytokines. Understanding how gp120 mediates a cytokine burst in monocytes might help develop new approaches to improve the chronic inflammation that persists in these patients despite effective suppression of viremia by antiretroviral therapy.
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87
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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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88
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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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89
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Liu Q, Acharya P, Dolan MA, Zhang P, Guzzo C, Lu J, Kwon A, Gururani D, Miao H, Bylund T, Chuang GY, Druz A, Zhou T, Rice WJ, Wigge C, Carragher B, Potter CS, Kwong PD, Lusso P. Quaternary contact in the initial interaction of CD4 with the HIV-1 envelope trimer. Nat Struct Mol Biol 2017; 24:370-378. [PMID: 28218750 DOI: 10.1038/nsmb.3382] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 01/25/2017] [Indexed: 12/19/2022]
Abstract
Binding of the gp120 envelope (Env) glycoprotein to the CD4 receptor is the first step in the HIV-1 infectious cycle. Although the CD4-binding site has been extensively characterized, the initial receptor interaction has been difficult to study because of major CD4-induced structural rearrangements. Here we used cryogenic electron microscopy (cryo-EM) to visualize the initial contact of CD4 with the HIV-1 Env trimer at 6.8-Å resolution. A single CD4 molecule is embraced by a quaternary HIV-1-Env surface formed by coalescence of the previously defined CD4-contact region with a second CD4-binding site (CD4-BS2) in the inner domain of a neighboring gp120 protomer. Disruption of CD4-BS2 destabilized CD4-trimer interaction and abrogated HIV-1 infectivity by preventing the acquisition of coreceptor-binding competence. A corresponding reduction in HIV-1 infectivity occurred after the mutation of CD4 residues that interact with CD4-BS2. Our results document the critical role of quaternary interactions in the initial HIV-Env-receptor contact, with implications for treatment and vaccine design.
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Affiliation(s)
- Qingbo Liu
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
| | - Priyamvada Acharya
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA.,National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, New York, USA
| | - Michael A Dolan
- Bioinformatics and Computational Biosciences Branch, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
| | - Peng Zhang
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
| | - Christina Guzzo
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
| | - Jacky Lu
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
| | - Alice Kwon
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
| | - Deepali Gururani
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
| | - Huiyi Miao
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
| | - Tatsiana Bylund
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
| | - Gwo-Yu Chuang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
| | - Aliaksandr Druz
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
| | - Tongqing Zhou
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
| | - William J Rice
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, New York, USA
| | - Christoph Wigge
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, New York, USA
| | - Bridget Carragher
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, New York, USA
| | - Clinton S Potter
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, New York, USA
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
| | - Paolo Lusso
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
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90
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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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91
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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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92
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van Gils MJ, van den Kerkhof TLGM, Ozorowski G, Cottrell CA, Sok D, Pauthner M, Pallesen J, de Val N, Yasmeen A, de Taeye SW, Schorcht A, Gumbs S, Johanna I, Saye-Francisco K, Liang CH, Landais E, Nie X, Pritchard LK, Crispin M, Kelsoe G, Wilson IA, Schuitemaker H, Klasse PJ, Moore JP, Burton DR, Ward AB, Sanders RW. An HIV-1 antibody from an elite neutralizer implicates the fusion peptide as a site of vulnerability. Nat Microbiol 2016; 2:16199. [PMID: 27841852 DOI: 10.1038/nmicrobiol.2016.199] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 09/09/2016] [Indexed: 01/12/2023]
Abstract
The induction by vaccination of broadly neutralizing antibodies (bNAbs) capable of neutralizing various HIV-1 viral strains is challenging, but understanding how a subset of HIV-infected individuals develops bNAbs may guide immunization strategies. Here, we describe the isolation and characterization of the bNAb ACS202 from an elite neutralizer that recognizes a new, trimer-specific and cleavage-dependent epitope at the gp120-gp41 interface of the envelope glycoprotein (Env), involving the glycan N88 and the gp41 fusion peptide. In addition, an Env trimer, AMC011 SOSIP.v4.2, based on early virus isolates from the same elite neutralizer, was constructed, and its structure by cryo-electron microscopy at 6.2 Å resolution reveals a closed, pre-fusion conformation similar to that of the BG505 SOSIP.664 trimer. The availability of a native-like Env trimer and a bNAb from the same elite neutralizer provides the opportunity to design vaccination strategies aimed at generating similar bNAbs against a key functional site on HIV-1.
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Affiliation(s)
- Marit J van Gils
- Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands.,Department of Immunology and Microbial Science, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery (CAVD), The Scripps Research Institute, La Jolla, California 92037, USA
| | - Tom L G M van den Kerkhof
- Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands.,Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
| | - Gabriel Ozorowski
- Department of Integrative Structural and Computational Biology, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery (CAVD), The Scripps Research Institute, La Jolla, California 92037, USA
| | - Christopher A Cottrell
- Department of Integrative Structural and Computational Biology, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery (CAVD), The Scripps Research Institute, La Jolla, California 92037, USA
| | - Devin Sok
- Department of Immunology and Microbial Science, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery (CAVD), The Scripps Research Institute, La Jolla, California 92037, USA
| | - Matthias Pauthner
- Department of Immunology and Microbial Science, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery (CAVD), The Scripps Research Institute, La Jolla, California 92037, USA
| | - Jesper Pallesen
- Department of Integrative Structural and Computational Biology, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery (CAVD), The Scripps Research Institute, La Jolla, California 92037, USA
| | - Natalia de Val
- Department of Integrative Structural and Computational Biology, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery (CAVD), The Scripps Research Institute, La Jolla, California 92037, USA
| | - Anila Yasmeen
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10021, USA
| | - Steven W de Taeye
- Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
| | - Anna Schorcht
- Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
| | - Stephanie Gumbs
- Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
| | - Inez Johanna
- Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
| | - Karen Saye-Francisco
- Department of Immunology and Microbial Science, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery (CAVD), The Scripps Research Institute, La Jolla, California 92037, USA
| | - Chi-Hui Liang
- Department of Immunology and Microbial Science, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery (CAVD), The Scripps Research Institute, La Jolla, California 92037, USA
| | - Elise Landais
- Department of Immunology and Microbial Science, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery (CAVD), The Scripps Research Institute, La Jolla, California 92037, USA
| | - Xiaoyan Nie
- Department of Immunology and Human Vaccine Institute, Duke University, Durham, North Carolina 27710, USA
| | - Laura K Pritchard
- Department of Biochemistry, Oxford Glycobiology Institute, University of Oxford, Oxford OX1 3QU, UK
| | - Max Crispin
- Department of Biochemistry, Oxford Glycobiology Institute, University of Oxford, Oxford OX1 3QU, UK
| | - Garnett Kelsoe
- Department of Immunology and Human Vaccine Institute, Duke University, Durham, North Carolina 27710, USA
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery (CAVD), The Scripps Research Institute, La Jolla, California 92037, USA
| | - Hanneke Schuitemaker
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands.,Janssen Pharmaceutical Companies of Johnson &Johnson, Archimedesweg 4-6, 2301 CA, Leiden, The Netherlands
| | - Per Johan Klasse
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10021, USA
| | - John P Moore
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10021, USA
| | - Dennis R Burton
- Department of Immunology and Microbial Science, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery (CAVD), The Scripps Research Institute, La Jolla, California 92037, USA.,Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard University, Cambridge, Massachusetts 02139, USA
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, Scripps CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery (CAVD), The Scripps Research Institute, La Jolla, California 92037, USA
| | - Rogier W Sanders
- Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands.,Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10021, USA
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93
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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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94
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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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95
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Klug YA, Rotem E, Schwarzer R, Shai Y. Mapping out the intricate relationship of the HIV envelope protein and the membrane environment. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1859:550-560. [PMID: 27793589 DOI: 10.1016/j.bbamem.2016.10.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/20/2016] [Accepted: 10/24/2016] [Indexed: 01/08/2023]
Abstract
The HIV gp160 envelope fusion protein is situated in the viral membrane and mediates virus entry into its host cell. Increasing evidence suggests that virtually all parts of the HIV envelope are structurally and functionally dependent on membranes. Protein-lipid interactions and membrane properties influence the dynamics of a manifold of gp160 biological activities such as membrane fusion, immune suppression and gp160 incorporation into virions during HIV budding and assembly. In the following we will summarize our current understanding of this interdependence between membrane interaction, structural conformation and functionality of the different gp160 domains. This article is part of a Special Issue entitled: Lipid order/lipid defects and lipid-control of protein activity edited by Dirk Schneider.
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Affiliation(s)
- Yoel A Klug
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Etai Rotem
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Roland Schwarzer
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Yechiel Shai
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
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96
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Williams KL, Cortez V, Dingens AS, Gach JS, Rainwater S, Weis JF, Chen X, Spearman P, Forthal DN, Overbaugh J. HIV-specific CD4-induced Antibodies Mediate Broad and Potent Antibody-dependent Cellular Cytotoxicity Activity and Are Commonly Detected in Plasma From HIV-infected humans. EBioMedicine 2016; 2:1464-77. [PMID: 26629541 PMCID: PMC4634620 DOI: 10.1016/j.ebiom.2015.09.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 08/31/2015] [Accepted: 09/01/2015] [Indexed: 01/12/2023] Open
Abstract
HIV-specific antibodies (Abs) can reduce viral burden by blocking new rounds of infection or by destroying infected cells via activation of effector cells through Fc–FcR interaction. This latter process, referred to as antibody-dependent cellular cytotoxicity (ADCC), has been associated with viral control and improved clinical outcome following both HIV and SIV infections. Here we describe an HIV viral-like particle (VLP)-based sorting strategy that led to identification of HIV-specificmemory B cells encoding Abs that mediate ADCC froma subtype A-infected Kenyan woman at 914 days post-infection. Using this strategy, 12 HIV-envelope-specific monoclonal antibodies (mAbs) were isolated and three mediated potent ADCC activitywhen compared to well-characterized ADCC mAbs. The ADCC-mediating Abs also mediated antibody-dependent cell-mediated virus inhibition (ADCVI), which provides a net measure of Fc receptor-triggered effects against replicating virus. Two of the three ADCC-mediating Abs targeted a CD4-induced (CD4i) epitope also bound by the mAb C11; the third antibody targeted the N-terminus of V3. Both CD4i Abs identified here demonstrated strong cross-clade breadth with activity against 10 of 11 envelopes tested, including those from clades A, B, C, A/D and C/D, whereas the V3-specific antibody showed more limited breadth. Variants of these CD4i, C11-like mAbs engineered to interrupt binding to FcγRs inhibited a measurable percentage of the donor's ADCC activity starting as early as 189 days post-infection. C11-like antibodies also accounted for between 18–78% of ADCC activity in 9 chronically infected individuals from the same cohort study. Further, the two CD4i Abs originated from unique B cells, suggesting that antibodies targeting this epitope can be commonly produced. Taken together, these data provide strong evidence that CD4i, C11-like antibodies develop within the first 6 months of infection and they can arise fromunique B-cell lineages in the same individual. Further, thesemAbsmediate potent plasma IgG-specificADCC breadth and potency and contribute to ADCC activity in other HIV-infected individuals.
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97
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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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98
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Richard J, Pacheco B, Gohain N, Veillette M, Ding S, Alsahafi N, Tolbert WD, Prévost J, Chapleau JP, Coutu M, Jia M, Brassard N, Park J, Courter JR, Melillo B, Martin L, Tremblay C, Hahn BH, Kaufmann DE, Wu X, Smith AB, Sodroski J, Pazgier M, Finzi A. Co-receptor Binding Site Antibodies Enable CD4-Mimetics to Expose Conserved Anti-cluster A ADCC Epitopes on HIV-1 Envelope Glycoproteins. EBioMedicine 2016; 12:208-218. [PMID: 27633463 PMCID: PMC5078604 DOI: 10.1016/j.ebiom.2016.09.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 09/07/2016] [Accepted: 09/07/2016] [Indexed: 11/06/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) has evolved a sophisticated strategy to conceal conserved epitopes of its envelope glycoproteins (Env) recognized by antibody-dependent cellular cytotoxicity (ADCC)-mediating antibodies. These antibodies, which are present in the sera of most HIV-1-infected individuals, preferentially recognize Env in its CD4-bound conformation. Accordingly, recent studies showed that small CD4-mimetics (CD4mc) able to “push” Env into this conformation sensitize HIV-1-infected cells to ADCC mediated by HIV + sera. Here we test whether CD4mc also expose epitopes recognized by anti-cluster A monoclonal antibodies such as A32, thought to be responsible for the majority of ADCC activity present in HIV + sera and linked to decreased HIV-1 transmission in the RV144 trial. We made the surprising observation that CD4mc are unable to enhance recognition of HIV-1-infected cells by this family of antibodies in the absence of antibodies such as 17b, which binds a highly conserved CD4-induced epitope overlapping the co-receptor binding site (CoRBS). Our results indicate that CD4mc initially open the trimeric Env enough to allow the binding of CoRBS antibodies but not anti-cluster A antibodies. CoRBS antibody binding further opens the trimeric Env, allowing anti-cluster A antibody interaction and sensitization of infected cells to ADCC. Therefore, ADCC responses mediated by cluster A antibodies in HIV-positive sera involve a sequential opening of the Env trimer on the surface of HIV-1-infected cells. The understanding of the conformational changes required to expose these vulnerable Env epitopes might be important in the design of new strategies aimed at fighting HIV-1. CD4-mimetics fail to enhance recognition of infected cells by anti-cluster A antibodies (Abs). Co-receptor binding site Abs in conjunction with CD4-mimetics allow binding of Env by anti-cluster A Abs. Co-receptor binding site Abs help CD4-mimetics sensitize HIV-1-infected cells to ADCC.
HIV-1 developed sophisticated strategies to conceal vulnerable epitopes of its envelope glycoproteins (Env) recognized by antibody-dependent cellular cytotoxicity (ADCC)-mediating antibodies. CD4-mimetics (CD4mc) were shown to sensitize HIV-1-infected cells to ADCC induced by HIV + sera. Here we show that this response requires a sequential opening of Env at the surface of HIV-1-infected cells. Co-receptor binding site antibodies, also present in HIV + sera, are required to expose ADCC-mediating epitopes recognized by anti-cluster A antibodies upon CD4mc addition. The understanding of the conformational changes required to expose anti-cluster A epitopes might be important in the design of new strategies aimed at fighting HIV-1.
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Affiliation(s)
- Jonathan Richard
- Centre de Recherche du CHUM, QC H2X 0A9, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, QC H2X 0A9, Canada.
| | | | - Neelakshi Gohain
- Institute of Human Virology, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Maxime Veillette
- Centre de Recherche du CHUM, QC H2X 0A9, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, QC H2X 0A9, Canada
| | - Shilei Ding
- Centre de Recherche du CHUM, QC H2X 0A9, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, QC H2X 0A9, Canada
| | - Nirmin Alsahafi
- Centre de Recherche du CHUM, QC H2X 0A9, Canada; Department of Microbiology and Immunology, McGill University, Montreal, QC H3A 2B4, Canada
| | - William D Tolbert
- Institute of Human Virology, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Jérémie Prévost
- Centre de Recherche du CHUM, QC H2X 0A9, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, QC H2X 0A9, Canada
| | - Jean-Philippe Chapleau
- Centre de Recherche du CHUM, QC H2X 0A9, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, QC H2X 0A9, Canada
| | | | - Manxue Jia
- Aaron Diamond AIDS Research Center, Affiliate of the Rockefeller University, New York, NY, USA
| | | | - Jongwoo Park
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Joel R Courter
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Bruno Melillo
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Loïc Martin
- CEA, iBiTecS, Service d'Ingénierie Moléculaire des Protéines, Gif sur Yvette, France
| | - Cécile Tremblay
- Centre de Recherche du CHUM, QC H2X 0A9, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, QC H2X 0A9, Canada
| | - Beatrice H Hahn
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6076, USA; Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6076, USA
| | - Daniel E Kaufmann
- Centre de Recherche du CHUM, QC H2X 0A9, Canada; Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard, Cambridge, MA 02139-3583, USA; Department of Medicine, Université de Montréal, Montreal, QC H3C 3T5, Canada; Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Xueling Wu
- Aaron Diamond AIDS Research Center, Affiliate of the Rockefeller University, New York, NY, USA
| | - Amos B Smith
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Department of Microbiology and Immunobiology, Division of AIDS, Harvard Medical School, Boston, MA 02115, USA; Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
| | - Marzena Pazgier
- Institute of Human Virology, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, 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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99
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Abstract
The HIV genome encodes a small number of viral proteins (i.e., 16), invariably establishing cooperative associations among HIV proteins and between HIV and host proteins, to invade host cells and hijack their internal machineries. As a known example, the HIV envelope glycoprotein GP120 is closely associated with GP41 for viral entry. From a genome-wide perspective, a hypothesis can be worked out to determine whether 16 HIV proteins could develop 120 possible pairwise associations either by physical interactions or by functional associations mediated via HIV or host molecules. Here, we present the first systematic review of experimental evidence on HIV genome-wide protein associations using a large body of publications accumulated over the past 3 decades. Of 120 possible pairwise associations between 16 HIV proteins, at least 34 physical interactions and 17 functional associations have been identified. To achieve efficient viral replication and infection, HIV protein associations play essential roles (e.g., cleavage, inhibition, and activation) during the HIV life cycle. In either a dispensable or an indispensable manner, each HIV protein collaborates with another viral protein to accomplish specific activities that precisely take place at the proper stages of the HIV life cycle. In addition, HIV genome-wide protein associations have an impact on anti-HIV inhibitors due to the extensive cross talk between drug-inhibited proteins and other HIV proteins. Overall, this study presents for the first time a comprehensive overview of HIV genome-wide protein associations, highlighting meticulous collaborations between all viral proteins during the HIV life cycle.
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Affiliation(s)
- Guangdi Li
- Department of Metabolism and Endocrinology, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China KU Leuven-University of Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Leuven, Belgium
| | - Erik De Clercq
- KU Leuven-University of Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Leuven, Belgium
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100
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HIV Genome-Wide Protein Associations: a Review of 30 Years of Research. Microbiol Mol Biol Rev 2016; 80:679-731. [PMID: 27357278 DOI: 10.1128/mmbr.00065-15] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The HIV genome encodes a small number of viral proteins (i.e., 16), invariably establishing cooperative associations among HIV proteins and between HIV and host proteins, to invade host cells and hijack their internal machineries. As a known example, the HIV envelope glycoprotein GP120 is closely associated with GP41 for viral entry. From a genome-wide perspective, a hypothesis can be worked out to determine whether 16 HIV proteins could develop 120 possible pairwise associations either by physical interactions or by functional associations mediated via HIV or host molecules. Here, we present the first systematic review of experimental evidence on HIV genome-wide protein associations using a large body of publications accumulated over the past 3 decades. Of 120 possible pairwise associations between 16 HIV proteins, at least 34 physical interactions and 17 functional associations have been identified. To achieve efficient viral replication and infection, HIV protein associations play essential roles (e.g., cleavage, inhibition, and activation) during the HIV life cycle. In either a dispensable or an indispensable manner, each HIV protein collaborates with another viral protein to accomplish specific activities that precisely take place at the proper stages of the HIV life cycle. In addition, HIV genome-wide protein associations have an impact on anti-HIV inhibitors due to the extensive cross talk between drug-inhibited proteins and other HIV proteins. Overall, this study presents for the first time a comprehensive overview of HIV genome-wide protein associations, highlighting meticulous collaborations between all viral proteins during the HIV life cycle.
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