151
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Grenier M, Ding S, Vézina D, Chapleau JP, Tolbert WD, Sherburn R, Schön A, Somisetti S, Abrams CF, Pazgier M, Finzi A, Smith AB. Optimization of Small Molecules That Sensitize HIV-1 Infected Cells to Antibody-Dependent Cellular Cytotoxicity. ACS Med Chem Lett 2020; 11:371-378. [PMID: 32184972 PMCID: PMC7074219 DOI: 10.1021/acsmedchemlett.9b00445] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 10/30/2019] [Indexed: 11/28/2022] Open
Abstract
With approximately 37 million people living with HIV worldwide and an estimated 2 million new infections reported each year, the need to derive novel strategies aimed at eradicating HIV-1 infection remains a critical worldwide challenge. One potential strategy would involve eliminating infected cells via antibody-dependent cellular cytotoxicity (ADCC). HIV-1 has evolved sophisticated mechanisms to conceal epitopes located in its envelope glycoprotein (Env) that are recognized by ADCC-mediating antibodies present in sera from HIV-1 infected individuals. Our aim is to circumvent this evasion via the development of small molecules that expose relevant anti-Env epitopes and sensitize HIV-1 infected cells to ADCC. Rapid elaboration of an initial screening hit using parallel synthesis and structure-based optimization has led to the development of potent small molecules that elicit this humoral response. Efforts to increase the ADCC activity of this class of small molecules with the aim of increasing their therapeutic potential was based on our recent cocrystal structures with gp120 core.
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Affiliation(s)
- Melissa
C. Grenier
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Shilei Ding
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et
Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Dani Vézina
- 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
| | - William D. Tolbert
- Infections Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, United States
| | - Rebekah Sherburn
- Infections Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, United States
| | - Arne Schön
- Department of Biology, The Johns Hopkins
University, Baltimore, Maryland 21218, United States
| | - Sambasivarao Somisetti
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Cameron F. Abrams
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Marzena Pazgier
- Infections Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, United States
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et
Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Amos B. Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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152
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Abstract
The HIV-1 Envelope (Env) is a metastable protein that displays several conformational states. In recent works, Lu et al. (2019) in Nature and Alsahafi et al. (2019) in Cell Host & Microbe show that antibodies displaying neutralization or antibody-dependent cellular cytotoxicity (ADCC) target different conformations of the viral glycoprotein.
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Affiliation(s)
- Timothée Bruel
- Virus & Immunity Unit, Institut Pasteur, UMR 3569, CNRS, Paris 75015, France; Vaccine Research Institute, Créteil, France.
| | - Olivier Schwartz
- Virus & Immunity Unit, Institut Pasteur, UMR 3569, CNRS, Paris 75015, France; Vaccine Research Institute, Créteil, France.
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153
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Li Y, Guo YC, Zhang XL, Deng L, Sang P, Yang LQ, Liu SQ. CD4-binding obstacles in conformational transitions and allosteric communications of HIV gp120. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183217. [PMID: 32061646 DOI: 10.1016/j.bbamem.2020.183217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 01/30/2020] [Accepted: 02/05/2020] [Indexed: 01/07/2023]
Abstract
As the only exposed viral protein at the membrane surface of HIV, envelope glycoprotein gp120 is responsible for recognizing host cells and mediating virus-cell membrane fusion. Available structures of gp120 indicate that it exhibits two distinct conformational states, called closed and open states. Although experimental data demonstrates that CD4 binding stabilizes open state of gp120, detailed structural dynamics and kinetics of gp120 during this process remain elusive. Here, two open-state gp120 simulation systems, one without any ligands (ligand-free) and the other complexed with CD4 (CD4-bound), were subjected to microsecond-scale molecular dynamics simulations following the conformational transitions and allosteric pathways of gp120 evaluated by using the Markov state model and a network-based method, respectively. Our results provide an atomic-resolution description of gp120 conformational transitions, suggesting that gp120 is intrinsically dynamic from the open state to closed state, whereas CD4 binding blocks these transitions. Consistent with experimental structures, five metastable conformations with different orientations of the V1/V2 region and V3 loop have been extracted. The binding of CD4 significantly enhances allosteric communications from the CD4-binding site to V3 loop and β20-21 hairpin, resulting in high-affinity interactions with coreceptors and activation of the conformational transitions switcher, respectively. This study will facilitate the structural understanding of the CD4-binding effects on conformational transitions and allosteric pathways of gp120.
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Affiliation(s)
- Yi Li
- College of Mathematics and Computer Science, Dali University, Dali, China
| | - Yu-Chen Guo
- College of Mathematics and Computer Science, Dali University, Dali, China
| | - Xiao-Ling Zhang
- College of Mathematics and Computer Science, Dali University, Dali, China
| | - Lei Deng
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China
| | - Peng Sang
- College of Agriculture and Biological Science, Dali University, Dali, China
| | - Li-Quan Yang
- College of Agriculture and Biological Science, Dali University, Dali, China.
| | - Shu-Qun Liu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.
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154
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Bangaru S, Lang S, Schotsaert M, Vanderven HA, Zhu X, Kose N, Bombardi R, Finn JA, Kent SJ, Gilchuk P, Gilchuk I, Turner HL, García-Sastre A, Li S, Ward AB, Wilson IA, Crowe JE. A Site of Vulnerability on the Influenza Virus Hemagglutinin Head Domain Trimer Interface. Cell 2020; 177:1136-1152.e18. [PMID: 31100268 DOI: 10.1016/j.cell.2019.04.011] [Citation(s) in RCA: 158] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 02/25/2019] [Accepted: 04/04/2019] [Indexed: 12/17/2022]
Abstract
Here, we describe the discovery of a naturally occurring human antibody (Ab), FluA-20, that recognizes a new site of vulnerability on the hemagglutinin (HA) head domain and reacts with most influenza A viruses. Structural characterization of FluA-20 with H1 and H3 head domains revealed a novel epitope in the HA trimer interface, suggesting previously unrecognized dynamic features of the trimeric HA protein. The critical HA residues recognized by FluA-20 remain conserved across most subtypes of influenza A viruses, which explains the Ab's extraordinary breadth. The Ab rapidly disrupted the integrity of HA protein trimers, inhibited cell-to-cell spread of virus in culture, and protected mice against challenge with viruses of H1N1, H3N2, H5N1, or H7N9 subtypes when used as prophylaxis or therapy. The FluA-20 Ab has uncovered an exceedingly conserved protective determinant in the influenza HA head domain trimer interface that is an unexpected new target for anti-influenza therapeutics and vaccines.
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Affiliation(s)
- Sandhya Bangaru
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Shanshan Lang
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Michael Schotsaert
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Hillary A Vanderven
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Xueyong Zhu
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Nurgun Kose
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Robin Bombardi
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jessica A Finn
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Stephen J Kent
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Pavlo Gilchuk
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Iuliia Gilchuk
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Hannah L Turner
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Sheng Li
- Department of Medicine and Biomedical Sciences, School of Medicine, University of California, San Diego, CA 92093, USA
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA; The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
| | - James E Crowe
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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155
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Das DK, Bulow U, Diehl WE, Durham ND, Senjobe F, Chandran K, Luban J, Munro JB. Conformational changes in the Ebola virus membrane fusion machine induced by pH, Ca2+, and receptor binding. PLoS Biol 2020; 18:e3000626. [PMID: 32040508 PMCID: PMC7034923 DOI: 10.1371/journal.pbio.3000626] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 02/21/2020] [Accepted: 01/23/2020] [Indexed: 12/22/2022] Open
Abstract
The Ebola virus (EBOV) envelope glycoprotein (GP) is a membrane fusion machine required for virus entry into cells. Following endocytosis of EBOV, the GP1 domain is cleaved by cellular cathepsins in acidic endosomes, removing the glycan cap and exposing a binding site for the Niemann-Pick C1 (NPC1) receptor. NPC1 binding to cleaved GP1 is required for entry. How this interaction translates to GP2 domain-mediated fusion of viral and endosomal membranes is not known. Here, using a bulk fluorescence dequenching assay and single-molecule Förster resonance energy transfer (smFRET)-imaging, we found that acidic pH, Ca2+, and NPC1 binding synergistically induce conformational changes in GP2 and permit virus-liposome lipid mixing. Acidic pH and Ca2+ shifted the GP2 conformational equilibrium in favor of an intermediate state primed for NPC1 binding. Glycan cap cleavage on GP1 enabled GP2 to transition from a reversible intermediate to an irreversible conformation, suggestive of the postfusion 6-helix bundle; NPC1 binding further promoted transition to the irreversible conformation. Thus, the glycan cap of GP1 may allosterically protect against inactivation of EBOV by premature triggering of GP2. The Ebola virus envelope glycoprotein is a membrane fusion machine required for the virus to enter into host cells. This study presents direct observation of the conformational changes that the envelope glycoprotein undergoes during the membrane fusion process.
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Affiliation(s)
- Dibyendu Kumar Das
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts, United States of America
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
- * E-mail: (JBM); (DKD)
| | - Uriel Bulow
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts, United States of America
| | - William E. Diehl
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Natasha D. Durham
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts, United States of America
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Fernando Senjobe
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts, United States of America
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Jeremy Luban
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - James B. Munro
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts, United States of America
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail: (JBM); (DKD)
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156
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Henderson R, Lu M, Zhou Y, Mu Z, Parks R, Han Q, Hsu AL, Carter E, Blanchard SC, Edwards RJ, Wiehe K, Saunders KO, Borgnia MJ, Bartesaghi A, Mothes W, Haynes BF, Acharya P, Munir Alam S. Disruption of the HIV-1 Envelope allosteric network blocks CD4-induced rearrangements. Nat Commun 2020; 11:520. [PMID: 31980614 PMCID: PMC6981184 DOI: 10.1038/s41467-019-14196-w] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 12/18/2019] [Indexed: 11/24/2022] Open
Abstract
The trimeric HIV-1 Envelope protein (Env) mediates viral-host cell fusion via a network of conformational transitions, with allosteric elements in each protomer orchestrating host receptor-induced exposure of the co-receptor binding site and fusion elements. To understand the molecular details of this allostery, here, we introduce Env mutations aimed to prevent CD4-induced rearrangements in the HIV-1 BG505 Env trimer. Binding analysis and single-molecule Förster Resonance Energy Transfer confirm that these mutations prevent CD4-induced transitions of the HIV-1 Env. Structural analysis by single-particle cryo-electron microscopy performed on the BG505 SOSIP mutant Env proteins shows rearrangements in the gp120 topological layer contacts with gp41. Displacement of a conserved tryptophan (W571) from its typical pocket in these Env mutants renders the Env insensitive to CD4 binding. These results reveal the critical function of W571 as a conformational switch in Env allostery and receptor-mediated viral entry and provide insights on Env conformation that are relevant for vaccine design.
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Affiliation(s)
- Rory Henderson
- Department of Medicine, Duke University School of Medicine, Durham, NC, 27710, USA.
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA.
| | - Maolin Lu
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, 06536, USA
| | - Ye Zhou
- Department of Computer Science, Duke University, Durham, NC, 27708, USA
| | - Zekun Mu
- Department of Immunology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Robert Parks
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Qifeng Han
- Department of Medicine, Duke University School of Medicine, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Allen L Hsu
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, 27709, USA
| | - Elizabeth Carter
- Department of Medicine, Duke University School of Medicine, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Scott C Blanchard
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, 10021, USA
- St. Jude Children's Research Hospital, Department of Structural Biology, 262 Danny Thomas Place, Memphis, TN, 38105-3678, USA
| | - R J Edwards
- Department of Medicine, Duke University School of Medicine, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Kevin Wiehe
- Department of Medicine, Duke University School of Medicine, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Kevin O Saunders
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA
- Department of Surgery, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Mario J Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, 27709, USA
| | - Alberto Bartesaghi
- Department of Computer Science, Duke University, Durham, NC, 27708, USA
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, 27710, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, 27708, USA
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, 06536, USA
| | - Barton F Haynes
- Department of Medicine, Duke University School of Medicine, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA
- Department of Immunology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Priyamvada Acharya
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA.
- Department of Surgery, Duke University School of Medicine, Durham, NC, 27710, USA.
| | - S Munir Alam
- Department of Medicine, Duke University School of Medicine, Durham, NC, 27710, USA.
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA.
- Department of Pathology, Duke University School of Medicine, Durham, NC, 27710, USA.
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157
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Durham ND, Howard AR, Govindan R, Senjobe F, Fels JM, Diehl WE, Luban J, Chandran K, Munro JB. Real-Time Analysis of Individual Ebola Virus Glycoproteins Reveals Pre-Fusion, Entry-Relevant Conformational Dynamics. Viruses 2020; 12:v12010103. [PMID: 31952255 PMCID: PMC7019799 DOI: 10.3390/v12010103] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/09/2020] [Accepted: 01/10/2020] [Indexed: 12/21/2022] Open
Abstract
The Ebola virus (EBOV) envelope glycoprotein (GP) mediates the fusion of the virion membrane with the membrane of susceptible target cells during infection. While proteolytic cleavage of GP by endosomal cathepsins and binding of the cellular receptor Niemann-Pick C1 protein (NPC1) are essential steps for virus entry, the detailed mechanisms by which these events promote membrane fusion remain unknown. Here, we applied single-molecule Förster resonance energy transfer (smFRET) imaging to investigate the structural dynamics of the EBOV GP trimeric ectodomain, and the functional transmembrane protein on the surface of pseudovirions. We show that in both contexts, pre-fusion GP is dynamic and samples multiple conformations. Removal of the glycan cap and NPC1 binding shift the conformational equilibrium, suggesting stabilization of conformations relevant to viral fusion. Furthermore, several neutralizing antibodies enrich alternative conformational states. This suggests that these antibodies neutralize EBOV by restricting access to GP conformations relevant to fusion. This work demonstrates previously unobserved dynamics of pre-fusion EBOV GP and presents a platform with heightened sensitivity to conformational changes for the study of GP function and antibody-mediated neutralization.
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Affiliation(s)
- Natasha D. Durham
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605, USA;
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, USA; (A.R.H.); (F.S.)
- Correspondence: (N.D.D.); (J.B.M.)
| | - Angela R. Howard
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, USA; (A.R.H.); (F.S.)
| | - Ramesh Govindan
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605, USA;
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, USA; (A.R.H.); (F.S.)
| | - Fernando Senjobe
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, USA; (A.R.H.); (F.S.)
| | - J. Maximilian Fels
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (J.M.F.); (K.C.)
| | - William E. Diehl
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA; (W.E.D.); (J.L.)
| | - Jeremy Luban
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA; (W.E.D.); (J.L.)
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (J.M.F.); (K.C.)
| | - James B. Munro
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605, USA;
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, USA; (A.R.H.); (F.S.)
- Correspondence: (N.D.D.); (J.B.M.)
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158
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Pan J, Peng H, Chen B, Harrison SC. Cryo-EM Structure of Full-length HIV-1 Env Bound With the Fab of Antibody PG16. J Mol Biol 2020; 432:1158-1168. [PMID: 31931014 DOI: 10.1016/j.jmb.2019.11.028] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 11/24/2019] [Accepted: 11/25/2019] [Indexed: 11/29/2022]
Abstract
The HIV-1 envelope protein (Env) is the target of neutralizing antibodies and the template for vaccine immunogen design. The dynamic conformational equilibrium of trimeric Env influences its antigenicity and potential immunogenicity. Antibodies that bind at the trimer apex stabilize a "closed" conformation characteristic of the most difficult to neutralize isolates. A goal of vaccine development is therefore to mimic the closed conformation in a designed immunogen. A disulfide-stabilized, trimeric Env ectodomain-the "SOSIP" construct-has many of the relevant properties; it is also particularly suitable for structure determination. Some single-molecule studies have, however, suggested that the SOSIP trimer is not a good representation of Env on the surface of a virion or an infected cell. We isolated Env (fully cleaved to gp120 and gp41) from the surface of expressing cells using tagged, apex-binding Fab PG16 and determined the structure of the PG16-Env complex by cryo-EM to an overall resolution of 4.6 Å. Placing the only purification tag on the Fab ensured that the isolated Env was continuously stabilized in its closed, native conformation. The Env structure in this complex corresponds closely to the SOSIP structures determined by both x-ray crystallography and cryo-EM. Although the membrane-interacting elements are not resolved in our reconstruction, we can make inferences about the connection between ectodomain and membrane-proximal external region (MPER) by reference to the published cryo-tomography structure of an Env "spike" and the NMR structure of the MPER-transmembrane segment. We discuss these results in view of the conflicting interpretations in the literature.
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Affiliation(s)
- Junhua Pan
- Laboratory of Molecular Medicine, Boston Children's Hospital, 3 Blackfan Circle, Boston, MA, 02115, USA
| | - Hanqin Peng
- Laboratory of Molecular Medicine, Boston Children's Hospital, 3 Blackfan Circle, Boston, MA, 02115, USA
| | - Bing Chen
- Laboratory of Molecular Medicine, Boston Children's Hospital, 3 Blackfan Circle, Boston, MA, 02115, USA
| | - Stephen C Harrison
- Laboratory of Molecular Medicine, Boston Children's Hospital, 3 Blackfan Circle, Boston, MA, 02115, USA; Howard Hughes Medical Institute, Boston Children's Hospital, 3 Blackfan Circle, Boston, MA, 02115, USA.
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159
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Yin W, Li W, Li Q, Liu Y, Liu J, Ren M, Ma Y, Zhang Z, Zhang X, Wu Y, Jiang S, Zhang XE, Cui Z. Real-time imaging of individual virion-triggered cortical actin dynamics for human immunodeficiency virus entry into resting CD4 T cells. NANOSCALE 2020; 12:115-129. [PMID: 31773115 DOI: 10.1039/c9nr07359k] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Real-time imaging of single virus particles allows the visualization of subtle dynamic events of virus-host interaction. During the human immunodeficiency virus (HIV) infection of resting CD4 T lymphocytes, overcoming cortical actin restriction is an essential step, but the dynamic process and mechanism remain to be characterized. Herein, by using quantum dot (QD) encapsulated fluorescent viral particles and single-virus tracking, we explored detailed scenarios of HIV dynamic entry and crossing the cortical actin barrier. The fine-scale temporal and spatial processes of single HIV virion interaction with the cortical actin were studied in depth during virus entry via plasma membrane fusion. Individual HIV virions modulate the subtle rearrangement of the cortical actin barrier to open a door to facilitate viral entry. The actin-binding protein, α-actinin, was found to be critical for actin dynamics during HIV entry. An α-actinin-derived peptide, actin-binding site 1 peptide (ABS1p), was developed to block HIV infection. Our findings reveal an α-actinin-mediated dynamic cortical actin rearrangement for HIV entry, and identify an antiviral target as well as a corresponding peptide inhibitor based on HIV interaction with the actin cytoskeleton.
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Affiliation(s)
- Wen Yin
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China. and University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Wei Li
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China.
| | - Qin Li
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China.
| | - Yuanyuan Liu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China. and University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Ji Liu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China. and University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Min Ren
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China. and University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yingxin Ma
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China.
| | - Zhiping Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China.
| | - Xiaowei Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China.
| | - Yuntao Wu
- National Center for Biodefense and Infectious Diseases, Department of Molecular and Microbiology, George Mason University, Manassas, Virginia 22030, USA
| | - Shibo Jiang
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Shanghai Medical College and Institute of Medical Microbiology, Fudan University, Shanghai 200032, People's Republic of China
| | - Xian-En Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
| | - Zongqiang Cui
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China.
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160
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Li Y, Zhang XL, Yuan X, Hou JC, Sang P, Yang LQ. Probing intrinsic dynamics and conformational transition of HIV gp120 by molecular dynamics simulation. RSC Adv 2020; 10:30499-30507. [PMID: 35516019 PMCID: PMC9056330 DOI: 10.1039/d0ra06416e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 10/07/2020] [Accepted: 08/04/2020] [Indexed: 11/21/2022] Open
Abstract
The HIV envelope glycoprotein gp120 has evolved two distinct conformational states to balance viral infection and immune escape. One is a closed state resistant to most neutralization antibodies, and the other is an open state responsible for the binding of the receptor and coreceptors. Although the structures of gp120 in these two conformational states have been determined, a detailed molecular mechanism involving intrinsic dynamics and conformational transition is still elusive. In this study, μs-scale molecular dynamics simulation is performed to probe molecular dynamics and conformational transition away from the open state and approach the closed state. Our results reveal that open gp120 shows a larger structural deviation, higher conformational flexibility, and more conformational diversity than the form in the closed state, providing a structural explanation for receptor or coreceptor affinity at the open state and the neutralization resistance of closed conformation. Seven regions with greatly decreased coupled motions in the open states have been observed by dynamic cross-correlation analysis, indicating that conformational transition can be mainly attributed to the relaxation of intrinsic dynamics. Three conformations characterized by the structural orientations of the V1/V2 region and the V3 loop, suggesting gp120 is intrinsically dynamic from the open state to the closed state. Taken together, these findings shed light on the understanding of the conformational control mechanism of HIV. The HIV envelope glycoprotein gp120 has evolved two distinct conformational states to balance viral infection and immune escape.![]()
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Affiliation(s)
- Yi Li
- College of Mathematics and Computer Science
- Dali University
- Dali
- China
- Science and Education Department
| | - Xiao-Ling Zhang
- College of Mathematics and Computer Science
- Dali University
- Dali
- China
| | - Xue Yuan
- College of Mathematics and Computer Science
- Dali University
- Dali
- China
| | - Jiang-Chun Hou
- Science and Education Department
- Second People's Hospital of Yunnan Province
- Kunming
- China
| | - Peng Sang
- College of Agriculture and Biological Science
- Dali University
- Dali
- China
| | - Li-Quan Yang
- College of Agriculture and Biological Science
- Dali University
- Dali
- China
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161
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Broadly neutralizing antibodies and vaccine design against HIV-1 infection. Front Med 2019; 14:30-42. [PMID: 31858368 PMCID: PMC8320319 DOI: 10.1007/s11684-019-0721-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Accepted: 09/07/2019] [Indexed: 12/31/2022]
Abstract
Remarkable progress has been achieved for prophylactic and therapeutic interventions against human immunodeficiency virus type I (HIV-1) through antiretroviral therapy. However, vaccine development has remained challenging. Recent discoveries in broadly neutralizing monoclonal antibodies (bNAbs) has led to the development of multiple novel vaccine approaches for inducing bNAbs-like antibody response. Structural and dynamic studies revealed several vulnerable sites and states of the HIV-1 envelop glycoprotein (Env) during infection. Our review aims to highlight these discoveries and rejuvenate our endeavor in HIV-1 vaccine design and development.
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162
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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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163
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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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164
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del Moral-Sánchez I, Sliepen K. Strategies for inducing effective neutralizing antibody responses against HIV-1. Expert Rev Vaccines 2019; 18:1127-1143. [PMID: 31791150 PMCID: PMC6961309 DOI: 10.1080/14760584.2019.1690458] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Introduction: Despite intensive research efforts, there is still no effective prophylactic vaccine available against HIV-1. Currently, substantial efforts are devoted to the development of vaccines aimed at inducing broadly neutralizing antibodies (bNAbs), which are capable of neutralizing most HIV-1 strains. All bNAbs target the HIV-1 envelope glycoprotein (Env), but Env immunizations usually only induce neutralizing antibodies (NAbs) against the sequence-matched virus and not against other strains.Areas covered: We describe the different strategies that have been explored to improve the breadth and potency of anti-HIV-1 NAb responses. The discussed strategies include the application of engineered Env immunogens, optimization of (bNAb) epitopes, different cocktail and sequential vaccination strategies, nanoparticles and nucleic acid-based vaccines.Expert opinion: A combination of the strategies described in this review and future approaches are probably needed to develop an effective HIV-1 vaccine that can induce broad, potent and long-lasting NAb responses.
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Affiliation(s)
- Iván del Moral-Sánchez
- Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Kwinten Sliepen
- Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands,CONTACT Kwinten Sliepen Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
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165
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Chen J, Park J, Kirk SM, Chen HC, Li X, Lippincott DJ, Melillo B, Smith AB. Development of an Effective Scalable Enantioselective Synthesis of the HIV-1 Entry Inhibitor BNM-III-170 as the Bis-Trifluoroacetate Salt. Org Process Res Dev 2019; 23:2464-2469. [PMID: 33013157 DOI: 10.1021/acs.oprd.9b00353] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report here the development and optimization of a process synthesis for the HIV-1 entry inhibitor BNM-III-170 bis-TFA salt (1). The synthesis features a dynamic-kinetic resolution (DKR) to establish the initial stereogenicity. By taking advantage of significant sequence modifications of our first generation synthesis, inconjunction with the low solubility of late-stage intermediates, the overall efficiency of the synthesis has been significantly improved, now to proceed in an overall yield of 9.64% for the 16-steps, requiring only a single chromatographic separation.
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Affiliation(s)
- Junhua Chen
- Department of Chemistry, Monell Chemical Senses Center and Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, PA 19104
| | - Jun Park
- Department of Chemistry, Monell Chemical Senses Center and Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, PA 19104
| | - Sharon M Kirk
- Department of Chemistry, Monell Chemical Senses Center and Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, PA 19104
| | - Hung-Ching Chen
- Department of Chemistry, Monell Chemical Senses Center and Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, PA 19104
| | - Xiangqin Li
- Department of Chemistry, Monell Chemical Senses Center and Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, PA 19104
| | - Daniel J Lippincott
- Department of Chemistry, Monell Chemical Senses Center and Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, PA 19104
| | - Bruno Melillo
- Department of Chemistry, Monell Chemical Senses Center and Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, PA 19104
| | - Amos B Smith
- Department of Chemistry, Monell Chemical Senses Center and Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, PA 19104
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166
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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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167
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Zhao C, Princiotto AM, Nguyen HT, Zou S, Zhao ML, Zhang S, Herschhorn A, Farrell M, Pahil K, Melillo B, Sambasivarao SV, Abrams C, Smith AB, Madani N, Sodroski J. Strain-Dependent Activation and Inhibition of Human Immunodeficiency Virus Entry by a Specific PF-68742 Stereoisomer. J Virol 2019; 93:e01197-19. [PMID: 31391272 PMCID: PMC6803283 DOI: 10.1128/jvi.01197-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 08/03/2019] [Indexed: 12/27/2022] Open
Abstract
Human immunodeficiency virus (HIV-1) entry into cells is mediated by the viral envelope glycoprotein (Env) trimer, which consists of three gp120 exterior glycoproteins and three gp41 transmembrane glycoproteins. When gp120 binds sequentially to the receptors CD4 and CCR5 on the target cell, the metastable Env trimer is triggered to undergo entry-related conformational changes. PF-68742 is a small molecule that inhibits the infection of a subset of HIV-1 strains by interfering with an Env function other than receptor binding. Determinants of HIV-1 resistance to PF-68742 map to the disulfide loop and fusion peptide of gp41. Of the four possible PF-68742 stereoisomers, only one, MF275, inhibited the infection of CD4-positive CCR5-positive cells by some HIV-1 strains. MF275 inhibition of these HIV-1 strains occurred after CD4 binding but before the formation of the gp41 six-helix bundle. Unexpectedly, MF275 activated the infection of CD4-negative CCR5-positive cells by several HIV-1 strains resistant to the inhibitory effects of the compound in CD4-positive target cells. In contrast to CD4 complementation by CD4-mimetic compounds, activation of CD4-independent infection by MF275 did not depend upon the availability of the gp120 Phe 43 cavity. Sensitivity to inhibitors indicates that MF275-activated virus entry requires formation/exposure of the gp41 heptad repeat (HR1) as well as CCR5 binding. MF275 apparently activates a virus entry pathway parallel to that triggered by CD4 and CD4-mimetic compounds. Strain-dependent divergence in Env conformational transitions allows different outcomes, inhibition or activation, in response to MF275. Understanding the mechanisms of MF275 activity should assist efforts to optimize its utility.IMPORTANCE Envelope glycoprotein (Env) spikes on the surface of human immunodeficiency virus (HIV-1) bind target cell receptors, triggering changes in the shape of Env. We studied a small molecule, MF275, that also induced shape changes in Env. The consequences of MF275 interaction with Env depended on the HIV-1 strain, with infection by some viruses inhibited and infection by other viruses enhanced. These studies reveal the strain-dependent diversity of HIV-1 Envs as they undergo shape changes in proceeding down the entry pathway. Appreciation of this diversity will assist attempts to develop broadly active inhibitors of HIV-1 entry.
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Affiliation(s)
- Connie Zhao
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Amy M Princiotto
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Hanh T Nguyen
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Shitao Zou
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Meiqing Lily Zhao
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Shijian Zhang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Alon Herschhorn
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Mark Farrell
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Karanbir Pahil
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Bruno Melillo
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Somisetti V Sambasivarao
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania, USA
| | - Cameron Abrams
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania, USA
| | - Amos B Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Navid Madani
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - 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
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168
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Finney J, Watanabe A, Kelsoe G, Kuraoka M. Minding the gap: The impact of B-cell tolerance on the microbial antibody repertoire. Immunol Rev 2019; 292:24-36. [PMID: 31559648 PMCID: PMC6935408 DOI: 10.1111/imr.12805] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 09/02/2019] [Indexed: 12/19/2022]
Abstract
B lymphocytes must respond to vast numbers of foreign antigens, including those of microbial pathogens. To do so, developing B cells use combinatorial joining of V-, D-, and J-gene segments to generate an extraordinarily diverse repertoire of B-cell antigen receptors (BCRs). Unsurprisingly, a large fraction of this initial BCR repertoire reacts to self-antigens, and these "forbidden" B cells are culled by immunological tolerance from mature B-cell populations. While culling of autoreactive BCRs mitigates the risk of autoimmunity, it also opens gaps in the BCR repertoire, which are exploited by pathogens that mimic the forbidden self-epitopes. Consequently, immunological tolerance, necessary for averting autoimmune disease, also acts to limit effective microbial immunity. In this brief review, we recount the evidence for the linkage of tolerance and impaired microbial immunity, consider the implications of this linkage for vaccine development, and discuss modulating tolerance as a potential strategy for strengthening humoral immune responses.
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Affiliation(s)
- Joel Finney
- Department of Immunology, Duke University, Durham, NC, USA
| | - Akiko Watanabe
- Department of Immunology, Duke University, Durham, NC, USA
| | - Garnett Kelsoe
- Department of Immunology, Duke University, Durham, NC, USA
- Duke University Human Vaccine Institute, Duke University, Durham, NC, USA
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169
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Einav T, Yazdi S, Coey A, Bjorkman PJ, Phillips R. Harnessing Avidity: Quantifying the Entropic and Energetic Effects of Linker Length and Rigidity for Multivalent Binding of Antibodies to HIV-1. Cell Syst 2019; 9:466-474.e7. [PMID: 31668801 PMCID: PMC6892280 DOI: 10.1016/j.cels.2019.09.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 09/10/2019] [Accepted: 09/17/2019] [Indexed: 12/13/2022]
Abstract
IgG antibodies increase their apparent affinities by using both of their Fabs to simultaneously attach to antigens. HIV-1 foils this strategy by having few, and highly separated, Envelope (Env) spike targets for antibodies, forcing most IgGs to bind monovalently. Here, we develop a statistical mechanics model of synthetic diFabs joined by DNA linkers of different lengths and flexibilities. This framework enables us to translate the energetic and entropic effects of the linker into the neutralization potency of a diFab. We demonstrate that the strongest neutralization potencies are predicted to require a rigid linker that optimally spans the distance between two Fab binding sites on an Env trimer and that avidity can be further boosted by incorporating more Fabs into these constructs. These results inform the design of multivalent anti-HIV-1 therapeutics that utilize avidity effects to remain potent against HIV-1 in the face of the rapid mutation of Env spikes. Synthetic antibodies that bivalently bind to HIV-1 can markedly enhance avidity Linkers that enable bivalent binding are fully characterized by the linker entropy Properly sized rigid linkers outperform long, flexible linkers Avidity can be further enhanced by increasing antibody valency
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Affiliation(s)
- Tal Einav
- Department of Physics, California Institute of Technology, Pasadena, CA 91125, USA
| | - Shahrzad Yazdi
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Aaron Coey
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Pamela J Bjorkman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Rob Phillips
- Department of Physics, California Institute of Technology, Pasadena, CA 91125, USA; Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Department of Applied Physics, California Institute of Technology, Pasadena, CA 91125, USA.
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170
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Agrawal P, DeVico AL, Foulke JS, Lewis GK, Pazgier M, Ray K. Stoichiometric Analyses of Soluble CD4 to Native-like HIV-1 Envelope by Single-Molecule Fluorescence Spectroscopy. Cell Rep 2019; 29:176-186.e4. [PMID: 31577947 PMCID: PMC6897359 DOI: 10.1016/j.celrep.2019.08.074] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 06/17/2019] [Accepted: 08/23/2019] [Indexed: 01/14/2023] Open
Abstract
Analyses of HIV-1 envelope (Env) binding to CD4, and the conformational changes the interactions induce, inform the molecular mechanisms and factors governing HIV-1 infection. To address these questions, we used a single-molecule detection (SMD) approach to study the nature of reactions between soluble CD4 (sCD4) and soluble HIV-1 trimers. SMD of these reactions distinguished a mixture of one, two, or three CD4-bound trimer species. Single-ligand trimers were favored at early reaction times and ligand-saturated trimers later. Furthermore, some trimers occupied by one sCD4 molecule did not bind additional ligands, whereas the majority of two ligand-bound species rapidly transitioned to the saturated state. Quantification of liganded trimers observed in reactions with various sCD4 concentrations reflected an overall negative cooperativity in ligand binding. Collectively, our results highlight the general utility of SMD in studying protein interactions and provide critical insights on the nature of sCD4-HIV-1 Env interactions.
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Affiliation(s)
- Parul Agrawal
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA
| | - Anthony L DeVico
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA; Department of Medicine, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA
| | - James S Foulke
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA
| | - George K Lewis
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA; Department of Microbiology and Immunology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA
| | - Marzena Pazgier
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA; Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA
| | - Krishanu Ray
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA; Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA.
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171
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Gao R, Fang Q, Zhang X, Xu Q, Ye H, Guo W, He J, Chen Y, Wang R, Wu Z, Yu J. R5 HIV-1 gp120 Activates p38 MAPK to Induce Rat Cardiomyocyte Injury by the CCR5 Coreceptor. Pathobiology 2019; 86:274-284. [PMID: 31574524 DOI: 10.1159/000502238] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 07/18/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Effective antiretroviral therapy extends the survival of patients with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome, but these patients remain at higher risk for heart diseases compared with the general population. Previous studies have suggested that HIV-1 glycoprotein 120 (gp120) may be associated with heart disease. However, the underlying mechanisms by which HIV-1 gp120-mediated myocardial injury occurs remain unknown. OBJECTIVE The current study aimed to uncover the mechanism of C-C chemokine receptor 5 (CCR5) coreceptor (R5) HIV-1 gp120-induced myocardial injury. METHODS Morphology analysis, determination of the percentage of cell apoptosis, as well as lactate dehydrogenase (LDH) and creatine kinase (CK) assays were used to analyze whether R5 HIV-1 gp120 induced myocardial cell injury. We analyzed the phosphorylation of p38 mitogen-activated protein kinase (MAPK) with the CCR5 antagonist D-Ala-peptide T-amide (DAPTA) and NMDA receptor antagonist MK801, detected LDH and CK assays with p38 MAPK antagonist SB203580 (SB), and detected the percentage of cell apoptosis and death with DAPTA to investigate the mechanism of R5 HIV-1 gp120-induced myocardial cell injury. RESULTS R5 HIV-1 gp120 damaged myocardial cells and induced p38 MAPK phosphorylation. SB blocked R5 HIV-1 gp120-induced myocardial cell injury. DAPTA blocked R5 HIV-1 gp120-mediated p38 MAPK phosphorylation, while MK801 did not. DAPTA inhibited R5 HIV-1 gp120-induced myocardial cell injury. CONCLUSION Our data indicate that R5 HIV-1 gp120 activated p38 MAPK to trigger myocardial cell injury by the CCR5 coreceptor.
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Affiliation(s)
- Rui Gao
- The Key Laboratory of Fujian Province University on Ion Channel and Signal Transduction in Cardiovascular Disease, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China.,Department of Pathology, Fujian Provincial Hospital, Provincial Clinical Medical College of Fujian Medical University, Fuzhou, China
| | - Qiujuan Fang
- The Key Laboratory of Fujian Province University on Ion Channel and Signal Transduction in Cardiovascular Disease, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China,
| | - Xi Zhang
- Department of Nursing, Fujian Provincial Hospital, Provincial Clinical Medical College of Fujian Medical University, Fuzhou, China
| | - Qin Xu
- School of Nursing, Fujian Medical University, Fuzhou, China
| | - Hanhui Ye
- Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, China
| | - Wenyan Guo
- The Key Laboratory of Fujian Province University on Ion Channel and Signal Transduction in Cardiovascular Disease, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Jiao He
- The Key Laboratory of Fujian Province University on Ion Channel and Signal Transduction in Cardiovascular Disease, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Yahong Chen
- Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, China
| | - Ruixing Wang
- The Key Laboratory of Fujian Province University on Ion Channel and Signal Transduction in Cardiovascular Disease, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Zhijuan Wu
- The Key Laboratory of Fujian Province University on Ion Channel and Signal Transduction in Cardiovascular Disease, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Jing Yu
- The Key Laboratory of Fujian Province University on Ion Channel and Signal Transduction in Cardiovascular Disease, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
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172
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Neutralization-guided design of HIV-1 envelope trimers with high affinity for the unmutated common ancestor of CH235 lineage CD4bs broadly neutralizing antibodies. PLoS Pathog 2019; 15:e1008026. [PMID: 31527908 PMCID: PMC6764681 DOI: 10.1371/journal.ppat.1008026] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/27/2019] [Accepted: 08/12/2019] [Indexed: 11/19/2022] Open
Abstract
The CD4 binding site (CD4bs) of the HIV-1 envelope glycoprotein is susceptible to multiple lineages of broadly neutralizing antibodies (bnAbs) that are attractive to elicit with vaccines. The CH235 lineage (VH1-46) of CD4bs bnAbs is particularly attractive because the most mature members neutralize 90% of circulating strains, do not possess long HCDR3 regions, and do not contain insertions and deletions that may be difficult to induce. We used virus neutralization to measure the interaction of CH235 unmutated common ancestor (CH235 UCA) with functional Env trimers on infectious virions to guide immunogen design for this bnAb lineage. Two Env mutations were identified, one in loop D (N279K) and another in V5 (G458Y), that acted synergistically to render autologous CH505 transmitted/founder virus susceptible to neutralization by CH235 UCA. Man5-enriched N-glycans provided additional synergy for neutralization. CH235 UCA bound with nanomolar affinity to corresponding soluble native-like Env trimers as candidate immunogens. A cryo-EM structure of CH235 UCA bound to Man5-enriched CH505.N279K.G458Y.SOSIP.664 revealed interactions of the antibody light chain complementarity determining region 3 (CDR L3) with the engineered Env loops D and V5. These results demonstrate that virus neutralization can directly inform vaccine design and suggest a germline targeting and reverse engineering strategy to initiate and mature the CH235 bnAb lineage. Despite a wealth of information on the epitopes, ontogeny, structure and maturation pathways of multiple epitope classes of HIV-1 broadly neutralizing antibodies (bnAbs), there has been little progress eliciting similar antibodies by vaccination. One major contributing factor is the failure of many candidate immunogens to engage germline reverted forms of bnAbs, making it unlikely that they will provide adequate stimulation of appropriate naïve B cells to initiate bnAb lineages. Here we used virus neutralization to identify two point mutations and a modified glycan profile that together render HIV-1 CH505 Env-pseudotyped virus highly susceptible to neutralization by a germline-reverted form of the CH235 lineage of CD4 binding site (CD4bs) bnAbs. These same modifications permit strong binding of corresponding soluble native-like CH505 Env trimers to germline-reverted CH235. These observations provide a conceptual framework for the design and testing of novel immunogens that aim to elicit the CH235 bnAb lineage.
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173
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Abstract
Neutralizing antibodies against human immunodeficiency virus subtype 1 (HIV-1) bind to its envelope glycoprotein (Env). Half of the molecular mass of Env is carbohydrate making it one of the most heavily glycosylated proteins known in nature. HIV-1 Env glycans are derived from the host and present a formidable challenge for host anti-glycan antibody induction. Anti-glycan antibody induction is challenging because anti-HIV-1 glycan antibodies should recognize Env antigen while not acquiring autoreactivity. Thus, the glycan network on HIV-1 Env is referred to as the glycan shield. Despite the challenges presented by immune recognition of host-derived glycans, neutralizing antibodies capable of binding the glycans on HIV-1 Env can be generated by the host immune system in the setting of HIV-1 infection. In particular, a cluster of high mannose glycans, including an N-linked glycan at position 332, form the high mannose patch and are targeted by a variety of broadly neutralizing antibodies. These high mannose patch-directed HIV-1 antibodies can be categorized into distinct categories based on their antibody paratope structure, neutralization activity, and glycan and peptide reactivity. Below we will compare and contrast each of these classes of HIV-1 glycan-dependent antibodies and describe vaccine design efforts to elicit each of these antibody types.
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174
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Hollingsworth LR, Lemkul JA, Bevan DR, Brown AM. HIV-1 Env gp41 Transmembrane Domain Dynamics Are Modulated by Lipid, Water, and Ion Interactions. Biophys J 2019; 115:84-94. [PMID: 29972814 DOI: 10.1016/j.bpj.2018.05.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 05/04/2018] [Accepted: 05/21/2018] [Indexed: 12/20/2022] Open
Abstract
The gp41 transmembrane domain (TMD) of the envelope glycoprotein of the human immunodeficiency virus modulates the conformation of the viral envelope spike, the only druggable target on the surface of the virion. Targeting the envelope glycoprotein with small-molecule and antibody therapies requires an understanding of gp41 TMD dynamics, which is often challenging given the difficulties in describing native membrane properties. Here, atomistic molecular dynamics simulations of a trimeric, prefusion gp41 TMD in a model, asymmetric viral membrane that mimics the native viral envelope were performed. Water and chloride ions were observed to permeate the membrane and interact with the highly conserved arginine bundle, (R696)3, at the center of the membrane and influenced TMD stability by creating a network of hydrogen bonds and electrostatic interactions. We propose that this (R696)3 - water - anion network plays an important role in viral fusion with the host cell by modulating protein conformational changes within the membrane. Additionally, R683 and R707 at the exofacial and cytofacial membrane-water interfaces, respectively, are anchored in the lipid headgroup region and serve as a junction point for stabilization of the termini. The membrane thins as a result of the tilting of the gp41 trimer with nearby lipids increasing in volume, leading to an entropic driving force for TMD conformational change. These results provide additional detail and perspective on the influence of certain lipid types on TMD dynamics and a rationale for targeting key residues of the TMD for therapeutic design. These insights into the molecular details of TMD membrane anchoring will build toward a greater understanding of the dynamics that lead to viral fusion with the host cell.
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Affiliation(s)
| | - Justin A Lemkul
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia; Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia
| | - David R Bevan
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia; Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia
| | - Anne M Brown
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia; Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia; University Libraries, Virginia Tech, Blacksburg, Virginia.
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175
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Developments in single-molecule and single-particle fluorescence-based approaches for studying viral envelope glycoprotein dynamics and membrane fusion. Adv Virus Res 2019; 104:123-146. [PMID: 31439147 DOI: 10.1016/bs.aivir.2019.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Fusion of viral and cellular membranes is an essential step in the entry pathway of all enveloped viruses. This is a dynamic and multistep process, which has been extensively studied, resulting in the endpoints of the reaction being firmly established, and many essential cellular factors identified. What remains is to elucidate the dynamic events that underlie this process, including the order and timing of glycoprotein conformational changes, receptor-binding events, and movement of the glycoprotein on the surface of the virion. Due to the inherently asynchronous nature of these dynamics, there has been an increased focus on the study of single virions and single molecules. These techniques provide researchers the high precision and resolution necessary to bridge the gaps in our understanding of viral membrane fusion. This review highlights the advancement of single-molecule and single-particle fluorescence-based techniques, with a specific focus on how these techniques have been used to study the dynamic nature of the viral fusion pathway.
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176
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Abstract
Single-molecule Förster resonance energy transfer (smFRET) imaging has emerged as a powerful tool to probe conformational dynamics of viral proteins, identify novel structural intermediates that are hiding in averaging population-based measurements, permit access to the energetics of transitions and as such to the precise molecular mechanisms of viral replication. One strength of smFRET is the capability of characterizing biological molecules in their fully hydrated/native state, which are not necessarily available to other structural methods. Elegant experimental design for physiologically relevant conditions, such as intact virions, has permitted the detection of previously unknown conformational states of viral glycoproteins, revealed asymmetric intermediates, and allowed access to the real-time imaging of conformational changes during viral fusion. As more laboratories are applying smFRET, our understanding of the molecular mechanisms and the dynamic nature of viral proteins throughout the virus life cycle are predicted to improve and assist the development of novel antiviral therapies and vaccine design.
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Affiliation(s)
- Maolin Lu
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, United States.
| | - Xiaochu Ma
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, United States
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, United States.
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177
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Duerr R, Gorny MK. V2-Specific Antibodies in HIV-1 Vaccine Research and Natural Infection: Controllers or Surrogate Markers. Vaccines (Basel) 2019; 7:vaccines7030082. [PMID: 31390725 PMCID: PMC6789775 DOI: 10.3390/vaccines7030082] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 07/26/2019] [Accepted: 07/27/2019] [Indexed: 12/20/2022] Open
Abstract
Most human immunodeficiency virus (HIV) vaccine trials have lacked efficacy and empirical vaccine lead targets are scarce. Thus far, the only independent correlate of reduced risk of HIV-1 acquisition in humans is elevated levels of V2-specific antibodies identified in the modestly protective RV144 vaccine trial. Ten years after RV144, human and non-human primate vaccine studies have reassessed the potential contribution of V2-specific antibodies to vaccine efficacy. In addition, studies of natural HIV-1 infection in humans have provided insight into the development of V1V2-directed antibody responses and their impact on clinical parameters and disease progression. Functionally diverse anti-V2 monoclonal antibodies were isolated and their structurally distinct V2 epitope regions characterized. After RV144, a plethora of research studies were performed using different model systems, immunogens, protocols, and challenge viruses. These diverse studies failed to provide a clear picture regarding the contribution of V2 antibodies to vaccine efficacy. Here, we summarize the biological functions and clinical findings associated with V2-specific antibodies and discuss their impact on HIV vaccine research.
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Affiliation(s)
- Ralf Duerr
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA.
| | - Miroslaw K Gorny
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
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178
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Brinkkemper M, Sliepen K. Nanoparticle Vaccines for Inducing HIV-1 Neutralizing Antibodies. Vaccines (Basel) 2019; 7:E76. [PMID: 31362378 PMCID: PMC6789800 DOI: 10.3390/vaccines7030076] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 07/23/2019] [Accepted: 07/25/2019] [Indexed: 01/01/2023] Open
Abstract
The enormous sequence diversity between human immunodeficiency virus type 1 (HIV-1) strains poses a major roadblock for generating a broadly protective vaccine. Many experimental HIV-1 vaccine efforts are therefore aimed at eliciting broadly neutralizing antibodies (bNAbs) that are capable of neutralizing the majority of circulating HIV-1 strains. The envelope glycoprotein (Env) trimer on the viral membrane is the sole target of bNAbs and the key component of vaccination approaches aimed at eliciting bNAbs. Multimeric presentation of Env on nanoparticles often plays a critical role in these strategies. Here, we will discuss the different aspects of nanoparticles in Env vaccination, including recent insights in immunological processes underlying their perceived advantages, the different nanoparticle platforms and the various immunogenicity studies that employed nanoparticles to improve (neutralizing) antibody responses against Env.
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Affiliation(s)
- Mitch Brinkkemper
- Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands
| | - Kwinten Sliepen
- Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands.
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179
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Zhou H, Chen Y, Zhang S, Niu P, Qin K, Jia W, Huang B, Zhang S, Lan J, Zhang L, Tan W, Wang X. Structural definition of a neutralization epitope on the N-terminal domain of MERS-CoV spike glycoprotein. Nat Commun 2019; 10:3068. [PMID: 31296843 PMCID: PMC6624210 DOI: 10.1038/s41467-019-10897-4] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 06/05/2019] [Indexed: 02/05/2023] Open
Abstract
Most neutralizing antibodies against Middle East respiratory syndrome coronavirus (MERS-CoV) target the receptor-binding domain (RBD) of the spike glycoprotein and block its binding to the cellular receptor dipeptidyl peptidase 4 (DPP4). The epitopes and mechanisms of mAbs targeting non-RBD regions have not been well characterized yet. Here we report the monoclonal antibody 7D10 that binds to the N-terminal domain (NTD) of the spike glycoprotein and inhibits the cell entry of MERS-CoV with high potency. Structure determination and mutagenesis experiments reveal the epitope and critical residues on the NTD for 7D10 binding and neutralization. Further experiments indicate that the neutralization by 7D10 is not solely dependent on the inhibition of DPP4 binding, but also acts after viral cell attachment, inhibiting the pre-fusion to post-fusion conformational change of the spike. These properties give 7D10 a wide neutralization breadth and help explain its synergistic effects with several RBD-targeting antibodies. Antibodies that target the N-terminal domain (NTD) of the MERS-CoV spike remain poorly characterized. Here, Zhou et al. report the structural and functional analysis of the NTD-targeting mAb 7D10 and show that it synergizes with antibodies targeting the receptor-binding domain against different MERS-CoV strains.
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Affiliation(s)
- Haixia Zhou
- The Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Collaborative Innovation Center for Biotherapy, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Yingzhu Chen
- Key Laboratory of Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, China CDC, 102206, Beijing, China.,Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Clinical Laboratory, Peking University Cancer Hospital & Institute, 100142, Beijing, China
| | - Shuyuan Zhang
- The Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Collaborative Innovation Center for Biotherapy, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Peihua Niu
- Key Laboratory of Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, China CDC, 102206, Beijing, China
| | - Kun Qin
- Key Laboratory of Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, China CDC, 102206, Beijing, China
| | - Wenxu Jia
- Comprehensive AIDS Research Center, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, 100084, Beijing, China
| | - Baoying Huang
- Key Laboratory of Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, China CDC, 102206, Beijing, China
| | - Senyan Zhang
- The Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Collaborative Innovation Center for Biotherapy, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Jun Lan
- The Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Collaborative Innovation Center for Biotherapy, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Linqi Zhang
- Comprehensive AIDS Research Center, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, 100084, Beijing, China
| | - Wenjie Tan
- Key Laboratory of Medical Virology, National Health and Family Planning Commission, National Institute for Viral Disease Control and Prevention, China CDC, 102206, Beijing, China.
| | - Xinquan Wang
- The Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Collaborative Innovation Center for Biotherapy, School of Life Sciences, Tsinghua University, 100084, Beijing, China. .,Collaborative Innovation Center for Biotherapy, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, 610065, Chengdu, China.
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180
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Shen Z, Liu S, Li X, Wan Z, Mao Y, Chen C, Liu W. Conformational change within the extracellular domain of B cell receptor in B cell activation upon antigen binding. eLife 2019; 8:42271. [PMID: 31290744 PMCID: PMC6620044 DOI: 10.7554/elife.42271] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 06/27/2019] [Indexed: 12/20/2022] Open
Abstract
B lymphocytes use B cell receptors (BCRs) to recognize antigens. It is still not clear how BCR transduces antigen-specific physical signals upon binding across cell membrane for the conversion to chemical signals, triggering downstream signaling cascades. It is hypothesized that through a series of conformational changes within BCR, antigen engagement in the extracellular domain of BCR is transduced to its intracellular domain. By combining site-specific labeling methodology and FRET-based assay, we monitored conformational changes in the extracellular domains within BCR upon antigen engagement. Conformational changes within heavy chain of membrane-bound immunoglobulin (mIg), as well as conformational changes in the spatial relationship between mIg and Igβ were observed. These conformational changes were correlated with the strength of BCR activation and were distinct in IgM- and IgG-BCR. These findings provide molecular mechanisms to explain the fundamental aspects of BCR activation and a framework to investigate ligand-induced molecular events in immune receptors.
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Affiliation(s)
- Zhixun Shen
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
| | - Sichen Liu
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
| | - Xinxin Li
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
| | - Zhengpeng Wan
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
| | - Youxiang Mao
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
| | - Chunlai Chen
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing, China
| | - Wanli Liu
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
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181
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Zolla-Pazner S, Alvarez R, Kong XP, Weiss S. Vaccine-induced V1V2-specific antibodies control and or protect against infection with HIV, SIV and SHIV. Curr Opin HIV AIDS 2019; 14:309-317. [PMID: 30994501 PMCID: PMC6542703 DOI: 10.1097/coh.0000000000000551] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
PURPOSE OF REVIEW In humans, only one independent immunologic correlate of reduced risk of HIV infection has been identified: a robust antibody (Ab) response to the V1V2 domain of the gp120 envelope (Env) protein. In recent years, the presence and level of V1V2-specific Abs has also been correlated with protection from SIV and SHIV infections. Here, we review the multitude of studies showing the in-vivo protective effects of V1V2 Abs and review their immunologic characteristics and antiviral functions. RECENT FINDINGS Structural and immunologic studies have defined four epitope families in the V1V2 domain: one epitope family, V2q, which preferentially presents as a quaternary structure of the Env trimer, and another epitope family (V2qt) which requires the quaternary trimeric Env structure; these two epitope types are recognized by two families of monoclonal Abs (mAbs)-V2q-specific and V2qt-specific mAbs-which display broad and potent neutralizing activity. A third epitope family, V2i, is present as a discontinuous conformational structure that overlays the α4β7 integrin binding motif, and a fourth epitope family (V2p) exists on V2 peptides. Antibodies specific for V2i and V2p epitopes display only poor neutralizing activity but effectively mediate other antiviral activities and have been correlated with control of and/or protection from HIV, SIV and SHIV. Notably, V2q and V2qt Abs have not been induced by any vaccines, but V2p and V2i Abs have been readily induced with various vaccines in nonhuman primates and humans. SUMMARY The correlation of vaccine-induced V2p and V2i Abs with protection from HIV, SIV and SHIV suggests that these Ab types are extremely important to induce with prophylactic vaccines.
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Affiliation(s)
- Susan Zolla-Pazner
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai
| | - Raymond Alvarez
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai
| | - Xiang-Peng Kong
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Svenja Weiss
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai
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182
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Han Q, Jones JA, Nicely NI, Reed RK, Shen X, Mansouri K, Louder M, Trama AM, Alam SM, Edwards RJ, Bonsignori M, Tomaras GD, Korber B, Montefiori DC, Mascola JR, Seaman MS, Haynes BF, Saunders KO. Difficult-to-neutralize global HIV-1 isolates are neutralized by antibodies targeting open envelope conformations. Nat Commun 2019; 10:2898. [PMID: 31263112 PMCID: PMC6602974 DOI: 10.1038/s41467-019-10899-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 06/03/2019] [Indexed: 12/21/2022] Open
Abstract
The HIV-1 envelope (Env) is the target for neutralizing antibodies and exists on the surface of virions in open or closed conformations. Difficult-to-neutralize viruses (tier 2) express Env in a closed conformation antigenic for broadly neutralizing antibodies (bnAbs) but not for third variable region (V3) antibodies. Here we show that select V3 macaque antibodies elicited by Env vaccination can neutralize 26% of otherwise tier 2 HIV-1 isolates in standardized virus panels. The V3 antibodies only bound to Env in its open conformation. Thus, Envs on tier 2 viruses sample a state where the V3 loop is not in its closed conformation position. Envelope second variable region length, glycosylation sites and V3 amino acids were signatures of neutralization sensitivity. This study determined that open conformations of Env with V3 exposed are present on a subset of otherwise neutralization-resistant virions, therefore neutralization of tier 2 HIV-1 does not always indicate bnAb induction.
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Affiliation(s)
- Qifeng Han
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - Julia A Jones
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - Nathan I Nicely
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - Rachel K Reed
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - Xiaoying Shen
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - Katayoun Mansouri
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
- Department of Cell Biology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Mark Louder
- Vaccine Research Center, National Instiftute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, MD, 20892, USA
| | - Ashley M Trama
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - S Munir Alam
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - Robert J Edwards
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
- Department of Cell Biology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Mattia Bonsignori
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - Georgia D Tomaras
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
- Department of Surgery, Duke University Medical Center, Durham, NC, 27710, USA
- Department of Microbiology and Molecular Genetics, Duke University Medical Center, Durham, NC, 27710, USA
- Department of Immunology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Bette Korber
- Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - David C Montefiori
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA
- Department of Surgery, Duke University Medical Center, Durham, NC, 27710, USA
| | - John R Mascola
- Vaccine Research Center, National Instiftute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, MD, 20892, USA
| | - Michael S Seaman
- Center for Virology and Vaccine Research, Israel Deaconess Medical Center, Boston, MA, 02115, USA
| | - Barton F Haynes
- Department of Medicine, Duke University Medical Center, Durham, NC, 27710, USA.
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA.
- Department of Immunology, Duke University Medical Center, Durham, NC, 27710, USA.
| | - Kevin O Saunders
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, 27710, USA.
- Department of Surgery, Duke University Medical Center, Durham, NC, 27710, USA.
- Department of Microbiology and Molecular Genetics, Duke University Medical Center, Durham, NC, 27710, USA.
- Department of Immunology, Duke University Medical Center, Durham, NC, 27710, USA.
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183
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CD4 Expression and Env Conformation Are Critical for HIV-1 Restriction by SERINC5. J Virol 2019; 93:JVI.00544-19. [PMID: 31043528 DOI: 10.1128/jvi.00544-19] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 04/25/2019] [Indexed: 12/29/2022] Open
Abstract
Serine incorporator 5 (SERINC5) is a recently identified restriction factor that strongly blocks HIV-1 entry but is counteracted by Nef. Notably, tier 1 HIV-1 Env proteins are sensitive to SERINC5, whereas the majority of tier 2/3 Env proteins are resistant to SERINC5, when viruses are produced from CD4-negative cells and tested by a single-round replication assay. Here, we investigated the Env-dependent SERINC5 antiviral mechanism by comparing tier 1 NL Env with tier 3 AD8 Env proteins. We found that when NL and AD8 viruses were inoculated into CD4+ T cells and human peripheral blood mononuclear cells (PBMCs), the propagation of the two viruses was restricted to a similar level when Nef was not expressed. Using a bimolecular fluorescence complementation (BiFC) assay, we detected Env-Env association and Env-SERINC5 interactions. A much greater level of NL Env-SERINC5 interactions was detected than was AD8 Env-SERINC5 interactions, which was further validated by immunoprecipitation assays. In addition, SERINC5 dissociated the NL Env trimeric complex more effectively than the AD8 Env trimeric complex when CD4 was not expressed. However, when CD4 was expressed, SERINC5 became more capable of interacting with AD8 Env and dissociating its trimeric complex. Moreover, AD8 and several other tier 2/3 viruses produced in the presence of CD4 became sensitive to SERINC5 when measured by the single-round replication assay. Because tier 1 and tier 2/3 Env trimers have open and closed conformations, respectively, and CD4 opens the closed conformation, we conclude that SERINC5 selectively dissociates Env trimers with an open conformation to restrict HIV-1 replication.IMPORTANCE Restriction factors provide the first line of defense against retrovirus infection by posing several blocks to the viral replication cycle. SERINC5 is a novel restriction factor that strongly blocks HIV-1 entry, although it is counteracted by Nef. Currently, it is still unclear how HIV-1 entry is blocked by SERINC5. Notably, this entry block is dependent on viral Env proteins. Laboratory-adapted HIV-1 strains are sensitive, whereas primary isolates are highly resistant to SERINC5. Env proteins mediate virus entry via extensive conformational rearrangements from a closed ground state to a CD4-bound open state. We detected Env-Env associations and Env-SERINC5 interactions in live cells by a novel bimolecular fluorescence assay. We demonstrate that CD4 expression increases the Env sensitivity to SERINC5 and allows SERINC5 to dissociate the Env complex, suggesting that SERINC5 restriction is dependent on Env conformation. Our results provide new insights into the poorly defined Env-dependent SERINC5 antiviral mechanism.
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184
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Chen B. Molecular Mechanism of HIV-1 Entry. Trends Microbiol 2019; 27:878-891. [PMID: 31262533 DOI: 10.1016/j.tim.2019.06.002] [Citation(s) in RCA: 161] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 05/20/2019] [Accepted: 06/05/2019] [Indexed: 11/19/2022]
Abstract
HIV-1 envelope glycoprotein [Env; trimeric (gp160)3 cleaved to (gp120/gp41)3] attaches the virion to a susceptible cell and induces fusion of viral and cell membranes to initiate infection. It interacts with the primary receptor CD4 and coreceptor (e.g., chemokine receptor CCR5 or CXCR4) to allow viral entry by triggering large structural rearrangements and unleashing the fusogenic potential of gp41 to induce membrane fusion. Recent advances in structural biology of HIV-1 Env and its complexes with the cellular receptors have revealed molecular details of HIV-1 entry and yielded new mechanistic insights. In this review, I summarize our latest understanding of the HIV-1 membrane fusion process and discuss possible pathways for productive viral entry.
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Affiliation(s)
- Bing Chen
- Division of Molecular Medicine, Boston Children's Hospital, and Department of Pediatrics, Harvard Medical School, 3 Blackfan Street, Boston, MA 02115, USA.
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185
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Broadly resistant HIV-1 against CD4-binding site neutralizing antibodies. PLoS Pathog 2019; 15:e1007819. [PMID: 31194843 PMCID: PMC6592578 DOI: 10.1371/journal.ppat.1007819] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 06/25/2019] [Accepted: 05/07/2019] [Indexed: 01/15/2023] Open
Abstract
Recently identified broadly neutralizing antibodies (bnAbs) show great potential for clinical interventions against HIV-1 infection. However, resistant strains may impose substantial challenges. Here, we report on the identification and characterization of a panel of HIV-1 strains with broad and potent resistance against a large number of bnAbs, particularly those targeting the CD4-binding site (CD4bs). Site-directed mutagenesis revealed that several key epitope mutations facilitate resistance and are located in the inner domain, loop D, and β23/loop V5/β24 of HIV-1 gp120. The resistance is largely correlated with binding affinity of antibodies to the envelope trimers expressed on the cell surface. Our results therefore demonstrate the existence of broadly resistant HIV-1 strains against CD4bs neutralizing antibodies. Treatment strategies based on the CD4bs bnAbs must overcome such resistance to achieve optimal clinical outcomes. Recently identified broadly neutralizing antibodies (bnAbs) show great potential for clinical interventions against HIV-1 infection. Among the bnAbs isolated to date, those targeting the CD4bs are the most abundant and thoroughly studied as they disrupt the crucial step of viral interaction with the cellular receptor molecule CD4. Despite the superior potency and breadth of these CD4bs bnAbs, each fails to neutralize a small but significant portion of pseudotyped virus panels. Here, we report on the identification and characterization of a panel of HIV-1 strains with broad and potent resistance against a large number of bnAbs, particularly those targeting the CD4bs. Resistance is largely attributed to mutated residues within the epitopes or steric hindrance imposed by the bulky side-chain or glycan shield of the mutated residues, and is largely correlated with reduced binding avidity of the antibody to the quaternary trimeric envelope protein expressed on the surface of the transfected cells. Treatment strategies based on the CD4bs bnAbs therefore must overcome such resistance to achieve optimal clinical outcomes.
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186
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Bignon EA, Albornoz A, Guardado-Calvo P, Rey FA, Tischler ND. Molecular organization and dynamics of the fusion protein Gc at the hantavirus surface. eLife 2019; 8:46028. [PMID: 31180319 PMCID: PMC6609335 DOI: 10.7554/elife.46028] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 06/10/2019] [Indexed: 01/01/2023] Open
Abstract
The hantavirus envelope glycoproteins Gn and Gc mediate virion assembly and cell entry, with Gc driving fusion of viral and endosomal membranes. Although the X-ray structures and overall arrangement of Gn and Gc on the hantavirus spikes are known, their detailed interactions are not. Here we show that the lateral contacts between spikes are mediated by the same 2-fold contacts observed in Gc crystals at neutral pH, allowing the engineering of disulfide bonds to cross-link spikes. Disrupting the observed dimer interface affects particle assembly and overall spike stability. We further show that the spikes display a temperature-dependent dynamic behavior at neutral pH, alternating between ‘open’ and ‘closed’ forms. We show that the open form exposes the Gc fusion loops but is off-pathway for productive Gc-induced membrane fusion and cell entry. These data also provide crucial new insights for the design of optimized Gn/Gc immunogens to elicit protective immune responses. Hantaviruses infect rodents and other small mammals, but do not harm them. When transmitted to humans, often through rodent urine, feces or saliva, they can cause serious and even fatal diseases. Currently, there are no known methods that effectively prevent hantavirus infections or treat the diseases that they cause. During an infection, viruses invade the cells of their host. A hantavirus interacts with target cells through proteins on its surface called Gn and Gc glycoproteins. Previous work has shown that these glycoproteins are organized in bundles of four Gn and four Gc proteins, termed spikes, which project from the membrane that surrounds the virus. The Gc protein changes shape when it is activated and exposes a hidden region that can insert into the membrane of the target cell. The Gc proteins then change shape again to force the cell to fuse with the viral membrane. This process allows the virus to be taken up into the cell, where it can replicate. While the structures of each viral glycoprotein have been determined in isolation, it was not known how they interact within the Gn/Gc spike. Such information is crucial to understand how the viruses infect cells and which areas are exposed to the immune system of the host – and so could be targeted by antiviral treatments. Bignon et al. have now identified the molecular contacts that occur between spikes and interconnect them into a grid-like lattice on the surface of the virus. Genetically altering specific sections of the Gc glycoprotein strengthened or weakened these contacts, which correspondingly increased or decreased how stable the spike was. Preventing the contacts from forming resulted in cells releasing fewer virus-like particles. Bignon et al. also show that at the body temperature of mammals, the shape of the spike fluctuates between an ‘open’ form that exposes the region of Gc that inserts into the cell membrane, and a ‘closed’ form that hides this region. However, when Gc is activated, the open form becomes unable to cause the viral and cell membranes to fuse together. Together, the results presented by Bignon et al. help us to understand how changes to the hantavirus surface enable the virus to infect cells. This knowledge will help researchers to design vaccines that protect against hantavirus infections.
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Affiliation(s)
- Eduardo A Bignon
- Laboratorio de Virología Molecular, Fundación Ciencia & Vida, Santiago, Chile
| | - Amelina Albornoz
- Laboratorio de Virología Molecular, Fundación Ciencia & Vida, Santiago, Chile
| | - Pablo Guardado-Calvo
- Structural Virology Unit, Virology Department, Institut Pasteur, CNRS UMR 3569, Paris, France
| | - Félix A Rey
- Structural Virology Unit, Virology Department, Institut Pasteur, CNRS UMR 3569, Paris, France
| | - Nicole D Tischler
- Laboratorio de Virología Molecular, Fundación Ciencia & Vida, Santiago, Chile
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187
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Dowd KA, Pierson TC. The Many Faces of a Dynamic Virion: Implications of Viral Breathing on Flavivirus Biology and Immunogenicity. Annu Rev Virol 2019; 5:185-207. [PMID: 30265634 DOI: 10.1146/annurev-virology-092917-043300] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Flaviviruses are arthropod-borne RNA viruses that are a significant threat to global health due to their widespread distribution, ability to cause severe disease in humans, and capacity for explosive spread following introduction into new regions. Members of this genus include dengue, tick-borne encephalitis, yellow fever, and Zika viruses. Vaccination has been a highly successful means to control flaviviruses, and neutralizing antibodies are an important component of a protective immune response. High-resolution structures of flavivirus structural proteins and virions, alone and in complex with antibodies, provide a detailed understanding of viral fusion mechanisms and virus-antibody interactions. However, mounting evidence suggests these structures provide only a snapshot of an otherwise structurally dynamic virus particle. The contribution of the structural ensemble arising from viral breathing to the biology, antigenicity, and immunity of flaviviruses is discussed, including implications for the development and evaluation of flavivirus vaccines.
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Affiliation(s)
- Kimberly A Dowd
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA; ,
| | - Theodore C Pierson
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA; ,
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188
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Anand SP, Grover JR, Tolbert WD, Prévost J, Richard J, Ding S, Baril S, Medjahed H, Evans DT, Pazgier M, Mothes W, Finzi A. Antibody-Induced Internalization of HIV-1 Env Proteins Limits Surface Expression of the Closed Conformation of Env. J Virol 2019; 93:e00293-19. [PMID: 30894474 PMCID: PMC6532100 DOI: 10.1128/jvi.00293-19] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 03/16/2019] [Indexed: 01/10/2023] Open
Abstract
To minimize immune responses against infected cells, HIV-1 limits the surface expression of its envelope glycoprotein (Env). Here, we demonstrate that this mechanism is specific for the Env conformation and affects the efficiency of antibody-dependent cellular cytotoxicity (ADCC). Using flow cytometry and confocal microscopy, we show that broadly neutralizing antibodies (bNAbs) targeting the "closed" conformation of Env induce its internalization from the surface. In contrast, non-neutralizing antibodies (nNAbs) are displayed on the cell surface for prolonged period of times. The bNAb-induced Env internalization can be decreased by blocking dynamin function, which translates into higher susceptibilities of infected cells to ADCC. Our results suggest that antibody-mediated Env internalization is a mechanism used by HIV-1 to evade immune responses against the "closed" conformation of Env expressed on HIV-1-infected cells.IMPORTANCE HIV-1 has evolved to acquire several strategies to limit the exposure of its envelope glycoproteins (Env) on the surface of infected cells. In this study, we show that antibody-induced Env internalization is conformation specific and reduces the susceptibility of infected cells to antibody-dependent cellular cytotoxicity (ADCC). Thus, a better understanding of this mechanism might help develop antibodies with improved capacities to mediate ADCC.
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Affiliation(s)
- Sai Priya Anand
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Jonathan R Grover
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - William D Tolbert
- Infectious Diseases Division, Department of Medicine of Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | | | - Shilei Ding
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Sophie Baril
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
| | | | - David T Evans
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, USA
- Wisconsin National Primate Research Center, University of Wisconsin, Madison, Wisconsin, USA
| | - Marzena Pazgier
- Infectious Diseases Division, Department of Medicine of Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
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189
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Balasubramaniam M, Pandhare J, Dash C. Immune Control of HIV. JOURNAL OF LIFE SCIENCES (WESTLAKE VILLAGE, CALIF.) 2019; 1:4-37. [PMID: 31468033 PMCID: PMC6714987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The human immunodeficiency virus (HIV) infection of the immune cells expressing the cluster of differentiation 4 cell surface glycoprotein (CD4+ cells) causes progressive decline of the immune system and leads to the acquired immunodeficiency syndrome (AIDS). The ongoing global HIV/AIDS pandemic has already claimed over 35 million lives. Even after 37 years into the epidemic, neither a cure is available for the 37 million people living with HIV (PLHIV) nor is a vaccine discovered to avert the millions of new HIV infections that continue to occur each year. If left untreated, HIV infection typically progresses to AIDS and, ultimately, causes death in a majority of PLHIV. The recommended combination antiretroviral therapy (cART) suppresses virus replication and viremia, prevents or delays progression to AIDS, reduces transmission rates, and lowers HIV-associated mortality and morbidity. However, because cART does not eliminate HIV, and an enduring pool of infected resting memory CD4+ T cells (latent HIV reservoir) is established early on, any interruption to cART leads to a relapse of viremia and disease progression. Hence, strict adherence to a life-long cART regimen is mandatory for managing HIV infection in PLHIV. The HIV-1-specific cytotoxic T cells expressing the CD8 glycoprotein (CD8+ CTL) limit the virus replication in vivo by recognizing the viral antigens presented by human leukocyte antigen (HLA) class I molecules on the infected cell surface and killing those cells. Nevertheless, CTLs fail to durably control HIV-1 replication and disease progression in the absence of cART. Intriguingly, <1% of cART-naive HIV-infected individuals called elite controllers/HIV controllers (HCs) exhibit the core features that define a HIV-1 "functional cure" outcome in the absence of cART: durable viral suppression to below the limit of detection, long-term non-progression to AIDS, and absence of viral transmission. Robust HIV-1-specific CTL responses and prevalence of protective HLA alleles associated with enduring HIV-1 control have been linked to the HC phenotype. An understanding of the molecular mechanisms underlying the CTL-mediated suppression of HIV-1 replication and disease progression in HCs carrying specific protective HLA alleles may yield promising insights towards advancing the research on HIV cure and prophylactic HIV vaccine.
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Affiliation(s)
- Muthukumar Balasubramaniam
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, TN – 37208. USA
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN – 37208. USA
| | - Jui Pandhare
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, TN – 37208. USA
- School of Graduate Studies and Research, Meharry Medical College, Nashville, TN – 37208. USA
| | - Chandravanu Dash
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, TN – 37208. USA
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN – 37208. USA
- School of Graduate Studies and Research, Meharry Medical College, Nashville, TN – 37208. USA
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190
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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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191
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Quantifying Anti-HIV Envelope-Specific Antibodies in Plasma from HIV Infected Individuals. Viruses 2019; 11:v11060487. [PMID: 31141927 PMCID: PMC6631318 DOI: 10.3390/v11060487] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/21/2019] [Accepted: 05/25/2019] [Indexed: 12/15/2022] Open
Abstract
Quantifying HIV Envelope (Env)-specific antibodies in HIV+ plasma is useful for interpreting antibody dependent cellular cytotoxicity assay results. HIV Env, the only viral protein expressed on the surface of infected cells, has a native trimeric closed conformation on cells infected with wild-type HIV. However, CD4+ uninfected bystander cells in HIV+ cell cultures bind gp120 shed from HIV+ cells exposing CD4-induced epitopes normally hidden in native Env. We used flow-cytometry based assays to quantify antibodies in HIV+ plasma specific for native trimeric Env or gp120/CD4 conjugates using CEM.NKr.CCR5 (CEM) cells infected with HIV (iCEM) or coated with recombinant gp120 (cCEM), as a surrogate for gp120+ HIV- bystander cells. Results from both assays were compared to those of a plate-based ELISA to monomeric gp120. The levels of Env-specific antibodies to cCEM and iCEM, measured by flow cytometry, and to gp120 by ELISA were positively correlated. More antibodies in HIV+ plasma recognized the gp120 conformation exposed on cCEM than on iCEM. Comparisons of plasma from untreated progressors, treated progressors, and elite controllers revealed that antibodies to Env epitopes were the lowest in treated progressors. Plasma from elite controllers and untreated progressors had similarly high levels of Env-specific antibodies, despite elite controllers having undetectable HIV viral loads, while untreated progressors maintained high viral loads.
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192
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Gilman MSA, Furmanova-Hollenstein P, Pascual G, B van 't Wout A, Langedijk JPM, McLellan JS. Transient opening of trimeric prefusion RSV F proteins. Nat Commun 2019; 10:2105. [PMID: 31068578 PMCID: PMC6506550 DOI: 10.1038/s41467-019-09807-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 04/02/2019] [Indexed: 01/19/2023] Open
Abstract
The respiratory syncytial virus (RSV) F glycoprotein is a class I fusion protein that mediates viral entry and is a major target of neutralizing antibodies. Structures of prefusion forms of RSV F, as well as other class I fusion proteins, have revealed compact trimeric arrangements, yet whether these trimeric forms can transiently open remains unknown. Here, we perform structural and biochemical studies on a recently isolated antibody, CR9501, and demonstrate that it enhances the opening of prefusion-stabilized RSV F trimers. The 3.3 Å crystal structure of monomeric RSV F bound to CR9501, combined with analysis of over 25 previously determined RSV F structures, reveals a breathing motion of the prefusion conformation. We also demonstrate that full-length RSV F trimers transiently open and dissociate on the cell surface. Collectively, these findings have implications for the function of class I fusion proteins, as well as antibody prophylaxis and vaccine development for RSV.
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MESH Headings
- Animals
- Antibodies, Neutralizing/chemistry
- Antibodies, Neutralizing/immunology
- Antibodies, Neutralizing/metabolism
- Antibodies, Viral/chemistry
- Antibodies, Viral/immunology
- Antibodies, Viral/metabolism
- B-Lymphocytes/virology
- Chlorocebus aethiops
- Computer Simulation
- Crystallography, X-Ray
- Drug Development
- HEK293 Cells
- HeLa Cells
- Humans
- Models, Molecular
- Protein Multimerization/physiology
- Respiratory Syncytial Virus Infections/immunology
- Respiratory Syncytial Virus Infections/prevention & control
- Respiratory Syncytial Virus Infections/virology
- Respiratory Syncytial Virus Vaccines/immunology
- Respiratory Syncytial Virus, Human/isolation & purification
- Respiratory Syncytial Virus, Human/physiology
- Vero Cells
- Viral Fusion Proteins/chemistry
- Viral Fusion Proteins/immunology
- Viral Fusion Proteins/metabolism
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Affiliation(s)
- Morgan S A Gilman
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, 03755, USA
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA
| | | | - Gabriel Pascual
- Janssen Immunosciences, World Without Disease Accelerator, San Diego, CA, 92121, USA
| | - Angélique B van 't Wout
- Janssen Prevention Center, Janssen Vaccines & Prevention B.V, Leiden, CN, 2333, The Netherlands
- AlphaBiomics, London, SW4 0PA, United Kingdom
| | | | - Jason S McLellan
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA.
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193
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Braun E, Hotter D, Koepke L, Zech F, Groß R, Sparrer KM, Müller JA, Pfaller CK, Heusinger E, Wombacher R, Sutter K, Dittmer U, Winkler M, Simmons G, Jakobsen MR, Conzelmann KK, Pöhlmann S, Münch J, Fackler OT, Kirchhoff F, Sauter D. Guanylate-Binding Proteins 2 and 5 Exert Broad Antiviral Activity by Inhibiting Furin-Mediated Processing of Viral Envelope Proteins. Cell Rep 2019; 27:2092-2104.e10. [DOI: 10.1016/j.celrep.2019.04.063] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 03/11/2019] [Accepted: 04/12/2019] [Indexed: 12/13/2022] Open
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194
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Bridging Vaccine-Induced HIV-1 Neutralizing and Effector Antibody Responses in Rabbit and Rhesus Macaque Animal Models. J Virol 2019; 93:JVI.02119-18. [PMID: 30842326 PMCID: PMC6498063 DOI: 10.1128/jvi.02119-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 02/20/2019] [Indexed: 12/13/2022] Open
Abstract
Nonneutralizing antibody functions have been associated with reduced infection risk, or control of virus replication, for HIV-1 and related viruses. It is therefore critical to evaluate development of these responses throughout all stages of preclinical testing. Rabbits are conventionally used to evaluate the ability of vaccine candidates to safely elicit antibodies that bind and neutralize HIV-1. However, it remained unexplored how effectively rabbits model the development of nonneutralizing antibody responses in primates. We administered identical HIV-1 vaccine regimens to rabbits and rhesus macaques and performed detailed comparisons of vaccine-induced antibody responses. We demonstrated that nonneutralizing HIV-specific antibody responses can be studied in the rabbit model and have identified aspects of these responses that are common, and those that are unique, to rabbits and rhesus macaques. Our findings will help determine how to best utilize preclinical rabbit and rhesus macaque models to accelerate HIV vaccine candidate testing in human trials. Studies in animal models are essential prerequisites for clinical trials of candidate HIV vaccines. Small animals, such as rabbits, are used to evaluate promising strategies prior to further immunogenicity and efficacy testing in nonhuman primates. Our goal was to determine how HIV-specific vaccine-elicited antibody responses, epitope specificity, and Fc-mediated functions in the rabbit model can predict those in the rhesus macaque (RM) model. Detailed comparisons of the HIV-1-specific IgG response were performed on serum from rabbits and RM given identical modified vaccinia virus Ankara-prime/gp120-boost immunization regimens. We found that vaccine-induced neutralizing antibody, gp120-binding antibody levels and immunodominant specificities, antibody-dependent cellular phagocytosis of HIV-1 virions, and antibody-dependent cellular cytotoxicity (ADCC) responses against gp120-coated target cells were similar in rabbits and RM. However, we also identified characteristics of humoral immunity that differed across species. ADCC against HIV-infected target cells was elicited in rabbits but not in RM, and we observed differences among subdominantly targeted epitopes. Human Fc receptor binding assays and analysis of antibody-cell interactions indicated that rabbit vaccine-induced antibodies effectively recruited and activated human natural killer cells, while vaccine-elicited RM antibodies were unable to activate either human or RM NK cells. Thus, our data demonstrate that both Fc-independent and Fc-dependent functions of rabbit antibodies can be measured with commonly used in vitro assays; however, the ability of immunogenicity studies performed in rabbits to predict responses in RM will vary depending on the particular immune parameter of interest. IMPORTANCE Nonneutralizing antibody functions have been associated with reduced infection risk, or control of virus replication, for HIV-1 and related viruses. It is therefore critical to evaluate development of these responses throughout all stages of preclinical testing. Rabbits are conventionally used to evaluate the ability of vaccine candidates to safely elicit antibodies that bind and neutralize HIV-1. However, it remained unexplored how effectively rabbits model the development of nonneutralizing antibody responses in primates. We administered identical HIV-1 vaccine regimens to rabbits and rhesus macaques and performed detailed comparisons of vaccine-induced antibody responses. We demonstrated that nonneutralizing HIV-specific antibody responses can be studied in the rabbit model and have identified aspects of these responses that are common, and those that are unique, to rabbits and rhesus macaques. Our findings will help determine how to best utilize preclinical rabbit and rhesus macaque models to accelerate HIV vaccine candidate testing in human trials.
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195
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Meuser ME, Rashad AA, Ozorowski G, Dick A, Ward AB, Cocklin S. Field-Based Affinity Optimization of a Novel Azabicyclohexane Scaffold HIV-1 Entry Inhibitor. Molecules 2019; 24:molecules24081581. [PMID: 31013646 PMCID: PMC6514670 DOI: 10.3390/molecules24081581] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/19/2019] [Accepted: 04/20/2019] [Indexed: 12/22/2022] Open
Abstract
Small-molecule HIV-1 entry inhibitors are an extremely attractive therapeutic modality. We have previously demonstrated that the entry inhibitor class can be optimized by using computational means to identify and extend the chemotypes available. Here we demonstrate unique and differential effects of previously published antiviral compounds on the gross structure of the HIV-1 Env complex, with an azabicyclohexane scaffolded inhibitor having a positive effect on glycoprotein thermostability. We demonstrate that modification of the methyltriazole-azaindole headgroup of these entry inhibitors directly effects the potency of the compounds, and substitution of the methyltriazole with an amine-oxadiazole increases the affinity of the compound 1000-fold over parental by improving the on-rate kinetic parameter. These findings support the continuing exploration of compounds that shift the conformational equilibrium of HIV-1 Env as a novel strategy to improve future inhibitor and vaccine design efforts.
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Affiliation(s)
- Megan E Meuser
- Department of Biochemistry & Molecular Biology, Drexel University College of Medicine, Rooms 10307, 10309, and 10315, 245 North 15th Street, Philadelphia, PA 19102, USA.
| | - Adel A Rashad
- Department of Biochemistry & Molecular Biology, Drexel University College of Medicine, Rooms 10307, 10309, and 10315, 245 North 15th Street, Philadelphia, PA 19102, USA.
| | - Gabriel Ozorowski
- Department of Integrative Structural and Computational Biology, Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, CA 92037, USA.
| | - Alexej Dick
- Department of Biochemistry & Molecular Biology, Drexel University College of Medicine, Rooms 10307, 10309, and 10315, 245 North 15th Street, Philadelphia, PA 19102, USA.
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, CA 92037, USA.
| | - Simon Cocklin
- Department of Biochemistry & Molecular Biology, Drexel University College of Medicine, Rooms 10307, 10309, and 10315, 245 North 15th Street, Philadelphia, PA 19102, USA.
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196
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Munro JB, Lee KK. Probing Structural Variation and Dynamics in the HIV-1 Env Fusion Glycoprotein. Curr HIV Res 2019; 16:5-12. [PMID: 29268688 DOI: 10.2174/1570162x16666171222110025] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 08/16/2017] [Accepted: 08/17/2017] [Indexed: 11/22/2022]
Abstract
BACKGROUND Recent advances in structural characterization of the HIV envelope glycoprotein (Env) have provided a high-resolution glimpse of the architecture of this target for neutralizing antibodies and the machinery responsible for mediating receptor binding and membrane fusion. These structures primarily capture the detailed organization of the receptor-naive, prefusion conformation of Env, but under native solution conditions Env is highly dynamic, sampling multiple conformational states as well as exhibiting local protein flexibility. METHODS Special emphasis is placed on the use of biophysical methods, including single-molecule fluorescence microscopy and hydrogen/deuterium-exchange mass spectrometry. RESULTS Using novel biophysical approaches, striking isolate-specific differences in Env's dynamic profile have been revealed that appear to underlie phenotypic differences of the viral isolates such as neutralization sensitivity and CD4 receptor reactivity. CONCLUSION Structural studies are complemented by novel biophysical investigations that enable visualization of the dynamics of HIV-1 Env under native conditions. These approaches will also enable us to gain new insights into the mechanisms of action of antibodies and drugs.
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Affiliation(s)
- James B Munro
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, United States
| | - Kelly K Lee
- Department of Medicinal Chemistry and Biological Physics Structure and Design Program, University of Washington, Seattle, WA, United States
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197
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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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198
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Conformation of the native HIV-1 envelope protein raises questions for vaccine design. Nature 2019; 568:321-322. [DOI: 10.1038/d41586-019-01085-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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199
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Lu M, Ma X, Castillo-Menendez LR, Gorman J, Alsahafi N, Ermel U, Terry DS, Chambers M, Peng D, Zhang B, Zhou T, Reichard N, Wang K, Grover JR, Carman BP, Gardner MR, Nikić-Spiegel I, Sugawara A, Arthos J, Lemke EA, Smith AB, Farzan M, Abrams C, Munro JB, McDermott AB, Finzi A, Kwong PD, Blanchard SC, Sodroski JG, Mothes W. Associating HIV-1 envelope glycoprotein structures with states on the virus observed by smFRET. Nature 2019; 568:415-419. [PMID: 30971821 PMCID: PMC6655592 DOI: 10.1038/s41586-019-1101-y] [Citation(s) in RCA: 126] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Accepted: 03/08/2019] [Indexed: 11/09/2022]
Abstract
The HIV-1 envelope glycoprotein (Env) trimer mediates cell entry and is
conformationally dynamic1–8. Imaging
by single-molecule fluorescence resonance energy transfer (smFRET) has revealed
that, on the surface of intact virions, mature pre-fusion Env transitions from a
pre-triggered conformation (state 1) through a default intermediate conformation
(state 2) to a conformation in which it is bound to three CD4 receptor molecules
(state 3)8–10. It is currently unclear how these
states relate to known structures. Breakthroughs in the structural
characterization of the HIV-1 Env trimer have previously been achieved by
generating soluble and proteolytically cleaved trimers of gp140 Env that are
stabilized by a disulfide bond, an isoleucine-to-proline substitution at residue
559 and a truncation at residue 664 (SOSIP.664 trimers)5,11–18.
Cryo-electron microscopy studies have been performed with C-terminally truncated
Env of the HIV-1JR-FL strain in complex with the antibody PGT15119. Both approaches have revealed similar
structures for Env. Although these structures have been presumed to represent
the pre-triggered state 1 of HIV-1 Env, this hypothesis has never directly been
tested. Here we use smFRET to compare the conformational states of Env trimers
used for structural studies with native Env on intact virus. We find that the
constructs upon which extant high-resolution structures are based predominantly
occupy downstream conformations that represent states 2 and 3. Therefore, the
structure of the pretriggered state-1 conformation of viral Env that has been
identified by smFRET and that is preferentially stabilized by many broadly
neutralizing antibodies—and thus of interest for the design of
immunogens—remains unknown.
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Affiliation(s)
- Maolin Lu
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Xiaochu Ma
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Luis R Castillo-Menendez
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Jason Gorman
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Nirmin Alsahafi
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada.,Centre de Recherche du CHUM (CRCHUM), Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Utz Ermel
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Daniel S Terry
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Michael Chambers
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Dongjun Peng
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Baoshan Zhang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Tongqing Zhou
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Nick Reichard
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Kevin Wang
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Jonathan R Grover
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Brennan P Carman
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Matthew R Gardner
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Ivana Nikić-Spiegel
- Werner Reichardt Centre for Integrative Neuroscience, University of Tuebingen, Tuebingen, Germany
| | - Akihiro Sugawara
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA
| | - James Arthos
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Edward A Lemke
- Departments of Biology and Chemistry, Pharmacy and Geosciences, Johannes Gutenberg University Mainz, Mainz, Germany.,Institute of Molecular Biology (IMB), Johannes Gutenberg University Mainz, Mainz, Germany.,Structural and Computational Biology Unit and Cell Biology and Biophysics Unit, EMBL, Heidelberg, Germany
| | - Amos B Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael Farzan
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Cameron Abrams
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, PA, USA
| | - James B Munro
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA
| | - Adrian B McDermott
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Andrés Finzi
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada.,Centre de Recherche du CHUM (CRCHUM), Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Scott C Blanchard
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA.
| | - Joseph G Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, USA. .,Department of Microbiology, Harvard Medical School, Boston, MA, USA.
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA.
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200
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Kalemera M, Mincheva D, Grove J, Illingworth CJR. Building a mechanistic mathematical model of hepatitis C virus entry. PLoS Comput Biol 2019; 15:e1006905. [PMID: 30883541 PMCID: PMC6445459 DOI: 10.1371/journal.pcbi.1006905] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 04/02/2019] [Accepted: 02/28/2019] [Indexed: 12/12/2022] Open
Abstract
The mechanism by which hepatitis C virus (HCV) gains entry into cells is a complex one, involving a broad range of host proteins. Entry is a critical phase of the viral lifecycle, and a potential target for therapeutic or vaccine-mediated intervention. However, the mechanics of HCV entry remain poorly understood. Here we describe a novel computational model of viral entry, encompassing the relationship between HCV and the key host receptors CD81 and SR-B1. We conduct experiments to thoroughly quantify the influence of an increase or decrease in receptor availability upon the extent of viral entry. We use these data to build and parameterise a mathematical model, which we then validate by further experiments. Our results are consistent with sequential HCV-receptor interactions, whereby initial interaction between the HCV E2 glycoprotein and SR-B1 facilitates the accumulation CD81 receptors, leading to viral entry. However, we also demonstrate that a small minority of viruses can achieve entry in the absence of SR-B1. Our model estimates the impact of the different obstacles that viruses must surmount to achieve entry; among virus particles attaching to the cell surface, around one third of viruses accumulate sufficient CD81 receptors, of which 4-8% then complete the subsequent steps to achieve productive infection. Furthermore, we make estimates of receptor stoichiometry; in excess of 10 receptors are likely to be required to achieve viral entry. Our model provides a tool to investigate the entry characteristics of HCV variants and outlines a framework for future quantitative studies of the multi-receptor dynamics of HCV entry.
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Affiliation(s)
- Mphatso Kalemera
- Institute of Immunity and Transplantation, Division of Infection and Immunity, University College London, United Kingdom
| | - Dilyana Mincheva
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Joe Grove
- Institute of Immunity and Transplantation, Division of Infection and Immunity, University College London, United Kingdom
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