1
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Rao PG, Lambert GS, Upadhyay C. Broadly neutralizing antibody epitopes on HIV-1 particles are exposed after virus interaction with host cells. J Virol 2023; 97:e0071023. [PMID: 37681958 PMCID: PMC10537810 DOI: 10.1128/jvi.00710-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 07/07/2023] [Indexed: 09/09/2023] Open
Abstract
The envelope (Env) glycoproteins on HIV-1 virions are the sole target of broadly neutralizing antibodies (bNAbs) and the focus of vaccines. However, many cross-reactive conserved epitopes are often occluded on virus particles, contributing to the evasion of humoral immunity. This study aimed to identify the Env epitopes that are exposed/occluded on HIV-1 particles and to investigate the mechanisms contributing to their masking. Using a flow cytometry-based assay, three HIV-1 isolates, and a panel of antibodies, we show that only select epitopes, including V2i, the gp120-g41 interface, and gp41-MPER, are accessible on HIV-1 particles, while V3, V2q, and select CD4bs epitopes are masked. These epitopes become accessible after allosteric conformational changes are induced by the pre-binding of select Abs, prompting us to test if similar conformational changes are required for these Abs to exhibit their neutralization capability. We tested HIV-1 neutralization where the virus-mAb mix was pre-incubated/not pre-incubated for 1 hour prior to adding the target cells. Similar levels of neutralization were observed under both assay conditions, suggesting that the interaction between virus and target cells sensitizes the virions for neutralization via bNAbs. We further show that lectin-glycan interactions can also expose these epitopes. However, this effect is dependent on the lectin specificity. Given that, bNAbs are ideal for providing sterilizing immunity and are the goal of current HIV-1 vaccine efforts, these data offer insight on how HIV-1 may occlude these vulnerable epitopes from the host immune response. In addition, the findings can guide the formulation of effective antibody combinations for therapeutic use. IMPORTANCE The human immunodeficiency virus (HIV-1) envelope (Env) glycoprotein mediates viral entry and is the sole target of neutralizing antibodies. Our data suggest that antibody epitopes including V2q (e.g., PG9, PGT145), CD4bs (e.g., VRC01, 3BNC117), and V3 (2219, 2557) are masked on HIV-1 particles. The PG9 and 2219 epitopes became accessible for binding after conformational unmasking was induced by the pre-binding of select mAbs. Attempts to understand the masking mechanism led to the revelation that interaction between virus and host cells is needed to sensitize the virions for neutralization by broadly neutralizing antibodies (bNAbs). These data provide insight on how bNAbs may gain access to these occluded epitopes to exert their neutralization effects and block HIV-1 infection. These findings have important implications for the way we evaluate the neutralizing efficacy of antibodies and can potentially guide vaccine design.
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Affiliation(s)
- Priyanka Gadam Rao
- Division of Infectious Disease, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Gregory S. Lambert
- Division of Infectious Disease, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Chitra Upadhyay
- Division of Infectious Disease, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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2
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Tong T, D’Addabbo A, Xu J, Chawla H, Nguyen A, Ochoa P, Crispin M, Binley JM. Impact of stabilizing mutations on the antigenic profile and glycosylation of membrane-expressed HIV-1 envelope glycoprotein. PLoS Pathog 2023; 19:e1011452. [PMID: 37549185 PMCID: PMC10434953 DOI: 10.1371/journal.ppat.1011452] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/17/2023] [Accepted: 07/16/2023] [Indexed: 08/09/2023] Open
Abstract
Recent HIV-1 vaccine development has centered on "near native" soluble envelope glycoprotein (Env) trimers that are artificially stabilized laterally (between protomers) and apically (between gp120 and gp41). These mutations have been leveraged for use in membrane-expressed Env mRNA vaccines, although their effects in this context are unclear. To address this question, we used virus-like particle (VLP) produced in 293T cells. Uncleaved (UNC) trimers were laterally unstable upon gentle lysis from membranes. However, gp120/gp41 processing improved lateral stability. Due to inefficient gp120/gp41 processing, UNC is incorporated into VLPs. A linker between gp120 and gp41 neither improved trimer stability nor its antigenic profile. An artificially introduced enterokinase cleavage site allowed post-expression gp120/gp41 processing, concomitantly increasing trimer stability. Gp41 N-helix mutations I559P and NT1-5 imparted lateral trimer stability, but also reduced gp120/gp41 processing and/or impacted V2 apex and interface NAb binding. I559P consistently reduced recognition by HIV+ human plasmas, further supporting antigenic differences. Mutations in the gp120 bridging sheet failed to stabilize membrane trimers in a pre-fusion conformation, and also reduced gp120/gp41 processing and exposed non-neutralizing epitopes. Reduced glycan maturation and increased sequon skipping were common side effects of these mutations. In some cases, this may be due to increased rigidity which limits access to glycan processing enzymes. In contrast, viral gp120 did not show glycan skipping. A second, minor species of high mannose gp160 was unaffected by any mutations and instead bypasses normal folding and glycan maturation. Including the full gp41 cytoplasmic tail led to markedly reduced gp120/gp41 processing and greatly increased the proportion of high mannose gp160. Remarkably, monoclonal antibodies were unable to bind to this high mannose gp160 in native protein gels. Overall, our findings suggest caution in leveraging stabilizing mutations in nucleic acid-based immunogens to ensure they impart valuable membrane trimer phenotypes for vaccine use.
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Affiliation(s)
- Tommy Tong
- San Diego Biomedical Research Institute, San Diego, California, United States of America
| | - Alessio D’Addabbo
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Jiamin Xu
- San Diego Biomedical Research Institute, San Diego, California, United States of America
| | - Himanshi Chawla
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Albert Nguyen
- San Diego Biomedical Research Institute, San Diego, California, United States of America
| | - Paola Ochoa
- San Diego Biomedical Research Institute, San Diego, California, United States of America
| | - Max Crispin
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - James M. Binley
- San Diego Biomedical Research Institute, San Diego, California, United States of America
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3
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Boutin M, Medjahed H, Nayrac M, Lotke R, Gendron-Lepage G, Bourassa C, Sauter D, Richard J, Finzi A. Temsavir Modulates HIV-1 Envelope Conformation by Decreasing Its Proteolytic Cleavage. Viruses 2023; 15:1189. [PMID: 37243275 PMCID: PMC10221371 DOI: 10.3390/v15051189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/10/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
HIV-1 envelope glycoproteins (Envs) mediate viral entry and represent a target of choice for small molecule inhibitors. One of them, temsavir (BMS-626529) prevents the interaction of the host cell receptor CD4 with Env by binding the pocket under the β20-β21 loop of the Env subunit gp120. Along with its capacity to prevent viral entry, temsavir stabilizes Env in its "closed" conformation. We recently reported that temsavir affects glycosylation, proteolytic processing, and overall conformation of Env. Here, we extend these results to a panel of primary Envs and infectious molecular clones (IMCs), where we observe a heterogeneous impact on Env cleavage and conformation. Our results suggest that the effect of temsavir on Env conformation is associated with its capacity to decrease Env processing. Indeed, we found that the effect of temsavir on Env processing affects the recognition of HIV-1-infected cells by broadly neutralizing antibodies and correlates with their capacity to mediate antibody-dependent cellular cytotoxicity (ADCC).
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Affiliation(s)
- Marianne Boutin
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada (M.N.)
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Halima Medjahed
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada (M.N.)
| | - Manon Nayrac
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada (M.N.)
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Rishikesh Lotke
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, 72076 Tübingen, Germany
| | | | | | - Daniel Sauter
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, 72076 Tübingen, Germany
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Jonathan Richard
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada (M.N.)
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada (M.N.)
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H3T 1J4, Canada
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4
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Rao PG, Lambert GS, Upadhyay C. Broadly Neutralizing Antibody Epitopes on HIV-1 Particles are exposed after Virus Interaction with Host Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.20.524996. [PMID: 36711466 PMCID: PMC9882293 DOI: 10.1101/2023.01.20.524996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The envelope glycoproteins (Env) on HIV-1 virions are the sole target of broadly neutralizing antibodies (bNAb) and the focus of vaccines. However, many cross-reactive conserved epitopes are often occluded on virus particles, contributing to the evasion of humoral immunity. This study aimed to identify the Env epitopes that are exposed/occluded on HIV-1 particles and to investigate the mechanisms contributing to their masking. Using a flow cytometry-based assay, three HIV-1 isolates, and a panel of antibodies, we show that only select epitopes including V2i, gp120-g41 interface, and gp41-MPER are accessible on HIV-1 particles, while V3, V2q, and select CD4bs epitopes are masked. These epitopes become accessible after allosteric conformational changes are induced by pre-binding of select Abs, prompting us to test if similar conformational changes are required for these Abs to exhibit their neutralization capability. We tested HIV-1 neutralization where virus-mAb mix was pre-incubated/not pre-incubated for one hour prior to adding the target cells. Similar levels of neutralization were observed under both assay conditions, suggesting that the interaction between virus and target cells sensitizes the virions for neutralization via bNAbs. We further show that lectin-glycan interactions can also expose these epitopes. However, this effect is dependent on the lectin specificity. Given that, bNAbs are the ideal for providing sterilizing immunity and are the goal of current HIV-1 vaccine efforts, these data offer insight on how HIV-1 may occlude these vulnerable epitopes from the host immune response. In addition, the findings can guide the formulation of effective antibody combinations for therapeutic use.
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5
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Nguyen HT, Wang Q, Anang S, Sodroski JG. Characterization of the Human Immunodeficiency Virus (HIV-1) Envelope Glycoprotein Conformational States on Infectious Virus Particles. J Virol 2023; 97:e0185722. [PMID: 36815832 PMCID: PMC10062176 DOI: 10.1128/jvi.01857-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 02/01/2023] [Indexed: 02/24/2023] Open
Abstract
Human immunodeficiency virus (HIV-1) entry into cells involves triggering of the viral envelope glycoprotein (Env) trimer ([gp120/gp41]3) by the primary receptor, CD4, and coreceptors, CCR5 or CXCR4. The pretriggered (State-1) conformation of the mature (cleaved) Env is targeted by broadly neutralizing antibodies (bNAbs), which are inefficiently elicited compared with poorly neutralizing antibodies (pNAbs). Here, we characterize variants of the moderately triggerable HIV-1AD8 Env on virions produced by an infectious molecular proviral clone; such virions contain more cleaved Env than pseudotyped viruses. We identified three types of cleaved wild-type AD8 Env trimers on virions: (i) State-1-like trimers preferentially recognized by bNAbs and exhibiting strong subunit association; (ii) trimers recognized by pNAbs directed against the gp120 coreceptor-binding region and exhibiting weak, detergent-sensitive subunit association; and (iii) a minor gp41-only population. The first Env population was enriched and the other Env populations reduced by introducing State-1-stabilizing changes in the AD8 Env or by treatment of the virions with crosslinker or the State-1-preferring entry inhibitor, BMS-806. These stabilized AD8 Envs were also more resistant to gp120 shedding induced by a CD4-mimetic compound or by incubation on ice. Conversely, a State-1-destabilized, CD4-independent AD8 Env variant exhibited weaker bNAb recognition and stronger pNAb recognition. Similar relationships between Env triggerability and antigenicity/shedding propensity on virions were observed for other HIV-1 strains. State-1 Envs on virions can be significantly enriched by minimizing the adventitious incorporation of uncleaved Env; stabilizing the pretriggered conformation by Env modification, crosslinking or BMS-806 treatment; strengthening Env subunit interactions; and using CD4-negative producer cells. IMPORTANCE Efforts to develop an effective HIV-1 vaccine have been frustrated by the inability to elicit broad neutralizing antibodies that recognize multiple virus strains. Such antibodies can bind a particular shape of the HIV-1 envelope glycoprotein trimer, as it exists on a viral membrane but before engaging receptors on the host cell. Here, we establish simple yet powerful assays to characterize the envelope glycoproteins in a natural context on virus particles. We find that, depending on the HIV-1 strain, some envelope glycoproteins change shape and fall apart, creating decoys that can potentially divert the host immune response. We identify requirements to keep the relevant envelope glycoprotein target for broad neutralizing antibodies intact on virus-like particles. These studies suggest strategies that should facilitate efforts to produce and use virus-like particles as vaccine immunogens.
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Affiliation(s)
- Hanh T. Nguyen
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Qian Wang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Saumya Anang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Joseph G. Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
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6
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Crooks ET, Almanza F, D’Addabbo A, Duggan E, Zhang J, Wagh K, Mou H, Allen JD, Thomas A, Osawa K, Korber BT, Tsybovsky Y, Cale E, Nolan J, Crispin M, Verkoczy LK, Binley JM. Engineering well-expressed, V2-immunofocusing HIV-1 envelope glycoprotein membrane trimers for use in heterologous prime-boost vaccine regimens. PLoS Pathog 2021; 17:e1009807. [PMID: 34679128 PMCID: PMC8565784 DOI: 10.1371/journal.ppat.1009807] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 11/03/2021] [Accepted: 10/07/2021] [Indexed: 02/07/2023] Open
Abstract
HIV-1 vaccine immunofocusing strategies may be able to induce broadly-reactive neutralizing antibodies (NAbs). Here, we engineered a panel of diverse, membrane-resident native HIV-1 trimers vulnerable to two broad targets-the V2 apex and fusion peptide (FP). Selection criteria included i) high expression and ii) infectious function, so that trimer neutralization sensitivity can be profiled in pseudovirus (PV) assays. Initially, we boosted the expression of 17 candidate trimers by truncating gp41 and introducing a gp120-gp41 SOS disulfide to prevent gp120 shedding. "Repairs" were made to fill glycan holes and eliminate other strain-specific aberrations. A new neutralization assay allowed PV infection when our standard assay was insufficient. Trimers with exposed V3 loops, a target of non-NAbs, were discarded. To try to increase V2-sensitivity, we removed clashing glycans and modified the C-strand. Notably, a D167N mutation improved V2-sensitivity in several cases. Glycopeptide analysis of JR-FL trimers revealed near complete sequon occupation and that filling the N197 glycan hole was well-tolerated. In contrast, sequon optimization and inserting/removing glycans at other positions frequently had global "ripple" effects on glycan maturation and sequon occupation throughout the gp120 outer domain and gp41. V2 MAb CH01 selectively bound to trimers with small high mannose glycans near the base of the V1 loop, thereby avoiding clashes. Knocking in a rare N49 glycan was found to perturb gp41 glycans, increasing FP NAb sensitivity-and sometimes improving expression. Finally, a biophysical analysis of VLPs revealed that i) ~25% of particles bear Env spikes, ii) spontaneous particle budding is high and only increases 4-fold upon Gag transfection, and iii) Env+ particles express ~30-40 spikes. Taken together, we identified 7 diverse trimers with a range of sensitivities to two targets to allow rigorous testing of immunofocusing vaccine concepts.
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Affiliation(s)
- Emma T. Crooks
- San Diego Biomedical Research Institute, San Diego, California, United States of America
| | - Francisco Almanza
- San Diego Biomedical Research Institute, San Diego, California, United States of America
| | - Alessio D’Addabbo
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Erika Duggan
- Scintillon Institute, San Diego, California, United States of America
- Cellarcus BioSciences, La Jolla, California, United States of America
| | - Jinsong Zhang
- San Diego Biomedical Research Institute, San Diego, California, United States of America
| | - Kshitij Wagh
- Theoretical Biology & Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Huihui Mou
- Department of Immunology and Microbial Science, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Joel D. Allen
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Alyssa Thomas
- San Diego Biomedical Research Institute, San Diego, California, United States of America
| | - Keiko Osawa
- San Diego Biomedical Research Institute, San Diego, California, United States of America
| | - Bette T. Korber
- Theoretical Biology & Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Yaroslav Tsybovsky
- Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, Maryland, United States of America
| | - Evan Cale
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - John Nolan
- Scintillon Institute, San Diego, California, United States of America
- Cellarcus BioSciences, La Jolla, California, United States of America
| | - Max Crispin
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Laurent K. Verkoczy
- San Diego Biomedical Research Institute, San Diego, California, United States of America
| | - James M. Binley
- San Diego Biomedical Research Institute, San Diego, California, United States of America
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7
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McCaul N, Quandte M, Bontjer I, van Zadelhoff G, Land A, Crooks ET, Binley JM, Sanders RW, Braakman I. Intramolecular quality control: HIV-1 envelope gp160 signal-peptide cleavage as a functional folding checkpoint. Cell Rep 2021; 36:109646. [PMID: 34469718 DOI: 10.1016/j.celrep.2021.109646] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 06/28/2021] [Accepted: 08/11/2021] [Indexed: 11/24/2022] Open
Abstract
Removal of the membrane-tethering signal peptides that target secretory proteins to the endoplasmic reticulum is a prerequisite for proper folding. While generally thought to be removed co-translationally, we report two additional post-targeting functions for the HIV-1 gp120 signal peptide, which remains attached until gp120 folding triggers its removal. First, the signal peptide improves folding fidelity by enhancing conformational plasticity of gp120 by driving disulfide isomerization through a redox-active cysteine. Simultaneously, the signal peptide delays folding by tethering the N terminus to the membrane, until assembly with the C terminus. Second, its carefully timed cleavage represents intramolecular quality control and ensures release of (only) natively folded gp120. Postponed cleavage and the redox-active cysteine are both highly conserved and important for viral fitness. Considering the ∼15% proteins with signal peptides and the frequency of N-to-C contacts in protein structures, these regulatory roles of signal peptides are bound to be more common in secretory-protein biogenesis.
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Affiliation(s)
- Nicholas McCaul
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Science4Life, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Matthias Quandte
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Science4Life, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Ilja Bontjer
- Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam Institute for Infection and Immunity, 1105 Amsterdam, the Netherlands
| | - Guus van Zadelhoff
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Science4Life, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Aafke Land
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Science4Life, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Ema T Crooks
- San Diego Biomedical Research Institute, 10865 Road to the Cure #100, San Diego, CA, USA
| | - James M Binley
- San Diego Biomedical Research Institute, 10865 Road to the Cure #100, San Diego, CA, USA
| | - Rogier W Sanders
- Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam Institute for Infection and Immunity, 1105 Amsterdam, the Netherlands; Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY 10021, USA
| | - Ineke Braakman
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Science4Life, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands.
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8
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Fries CN, Curvino EJ, Chen JL, Permar SR, Fouda GG, Collier JH. Advances in nanomaterial vaccine strategies to address infectious diseases impacting global health. NATURE NANOTECHNOLOGY 2021; 16:1-14. [PMID: 32807876 DOI: 10.1038/s41565-020-0739-9] [Citation(s) in RCA: 108] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 06/23/2020] [Indexed: 05/18/2023]
Abstract
Despite the overwhelming success of vaccines in preventing infectious diseases, there remain numerous globally devastating diseases without fully protective vaccines, particularly human immunodeficiency virus (HIV), malaria and tuberculosis. Nanotechnology approaches are being developed both to design new vaccines against these diseases as well as to facilitate their global implementation. The reasons why a given pathogen may present difficulties for vaccine design are unique and tied to the co-evolutionary history of the pathogen and humans, but there are common challenges that nanotechnology is beginning to help address. In each case, a successful vaccine will need to raise immune responses that differ from the immune responses raised by normal infection. Nanomaterials, with their defined compositions, commonly modular construction, and length scales allowing the engagement of key immune pathways, collectively facilitate the iterative design process necessary to identify such protective immune responses and achieve them reliably. Nanomaterials also provide strategies for engineering the trafficking and delivery of vaccine components to key immune cells and lymphoid tissues, and they can be highly multivalent, improving their engagement with the immune system. This Review will discuss these aspects along with recent nanomaterial advances towards vaccines against infectious disease, with a particular emphasis on HIV/AIDS, malaria and tuberculosis.
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Affiliation(s)
- Chelsea N Fries
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | | | - Jui-Lin Chen
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, USA
| | - Sallie R Permar
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, USA
- Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
- Department of Immunology, Duke University School of Medicine, Durham, NC, USA
| | - Genevieve G Fouda
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA.
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, USA.
- Department of Pediatrics, Duke University Medical Center, Durham, NC, USA.
| | - Joel H Collier
- Department of Biomedical Engineering, Duke University, Durham, NC, USA.
- Department of Immunology, Duke University School of Medicine, Durham, NC, USA.
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9
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Immunogenicity of HIV-1-Based Virus-Like Particles with Increased Incorporation and Stability of Membrane-Bound Env. Vaccines (Basel) 2021; 9:vaccines9030239. [PMID: 33801906 PMCID: PMC8002006 DOI: 10.3390/vaccines9030239] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/04/2021] [Accepted: 03/05/2021] [Indexed: 01/04/2023] Open
Abstract
An optimal prophylactic vaccine to prevent human immunodeficiency virus (HIV-1) transmission should elicit protective antibody responses against the HIV-1 envelope glycoprotein (Env). Replication-incompetent HIV-1 virus-like particles (VLPs) offer the opportunity to present virion-associated Env with a native-like structure during vaccination that closely resembles that encountered on infectious virus. Here, we optimized the incorporation of Env into previously designed mature-form VLPs (mVLPs) and assessed their immunogenicity in mice. The incorporation of Env into mVLPs was increased by replacing the Env transmembrane and cytoplasmic tail domains with those of influenza haemagglutinin (HA-TMCT). Furthermore, Env was stabilized on the VLP surface by introducing an interchain disulfide and proline substitution (SOSIP) mutations typically employed to stabilize soluble Env trimers. The resulting mVLPs efficiently presented neutralizing antibody epitopes while minimizing exposure of non-neutralizing antibody sites. Vaccination of mice with mVLPs elicited a broader range of Env-specific antibody isotypes than Env presented on immature VLPs or extracellular vesicles. The mVLPs bearing HA-TMCT-modified Env consistently induced anti-Env antibody responses that mediated modest neutralization activity. These mVLPs are potentially useful immunogens for eliciting neutralizing antibody responses that target native Env epitopes on infectious HIV-1 virions.
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10
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Dual Pathways of Human Immunodeficiency Virus Type 1 Envelope Glycoprotein Trafficking Modulate the Selective Exclusion of Uncleaved Oligomers from Virions. J Virol 2021; 95:JVI.01369-20. [PMID: 33148792 DOI: 10.1128/jvi.01369-20] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 10/24/2020] [Indexed: 12/14/2022] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) trimer is transported through the secretory pathway to the infected cell surface and onto virion particles. In the Golgi, the gp160 Env precursor is modified by complex sugars and proteolytically cleaved to produce the mature functional Env trimer, which resists antibody neutralization. We observed mostly uncleaved gp160 and smaller amounts of cleaved gp120 and gp41 Envs on the surface of HIV-1-infected or Env-expressing cells; however, cleaved Envs were relatively enriched in virions and virus-like particles (VLPs). This relative enrichment of cleaved Env in VLPs was observed for wild-type Envs, for Envs lacking the cytoplasmic tail, and for CD4-independent, conformationally flexible Envs. On the cell surface, we identified three distinct populations of Envs: (i) the cleaved Env was transported through the Golgi, was modified by complex glycans, formed trimers that cross-linked efficiently, and was recognized by broadly neutralizing antibodies; (ii) a small fraction of Env modified by complex carbohydrates escaped cleavage in the Golgi; and (iii) the larger population of uncleaved Env lacked complex carbohydrates, cross-linked into diverse oligomeric forms, and was recognized by poorly neutralizing antibodies. This last group of more "open" Env oligomers reached the cell surface in the presence of brefeldin A, apparently bypassing the Golgi apparatus. Relative to Envs transported through the Golgi, these uncleaved Envs were counterselected for virion incorporation. By employing two pathways for Env transport to the surface of infected cells, HIV-1 can misdirect host antibody responses toward conformationally flexible, uncleaved Env without compromising virus infectivity.IMPORTANCE The envelope glycoprotein (Env) trimers on the surface of human immunodeficiency virus type 1 (HIV-1) mediate the entry of the virus into host cells and serve as targets for neutralizing antibodies. The cleaved, functional Env is incorporated into virus particles from the surface of the infected cell. We found that an uncleaved form of Env is transported to the cell surface by an unconventional route, but this nonfunctional Env is mostly excluded from the virus. Thus, only one of the pathways by which Env is transported to the surface of infected cells results in efficient incorporation into virus particles, potentially allowing the uncleaved Env to act as a decoy to the host immune system without compromising virus infectivity.
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11
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Signal peptide of HIV-1 envelope modulates glycosylation impacting exposure of V1V2 and other epitopes. PLoS Pathog 2020; 16:e1009185. [PMID: 33370382 PMCID: PMC7793277 DOI: 10.1371/journal.ppat.1009185] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 01/08/2021] [Accepted: 11/24/2020] [Indexed: 11/19/2022] Open
Abstract
HIV-1 envelope (Env) is a trimer of gp120-gp41 heterodimers, synthesized from a precursor gp160 that contains an ER-targeting signal peptide (SP) at its amino-terminus. Each trimer is swathed by ~90 N-linked glycans, comprising complex-type and oligomannose-type glycans, which play an important role in determining virus sensitivity to neutralizing antibodies. We previously examined the effects of single point SP mutations on Env properties and functions. Here, we aimed to understand the impact of the SP diversity on glycosylation of virus-derived Env and virus neutralization by swapping SPs. Analyses of site-specific glycans revealed that SP swapping altered Env glycan content and occupancy on multiple N-linked glycosites, including conserved N156 and N160 glycans in the V1V2 region at the Env trimer apex and N88 at the trimer base. Virus neutralization was also affected, especially by antibodies against V1V2, V3, and gp41. Likewise, SP swaps affected the recognition of soluble and cell-associated Env by antibodies targeting distinct V1V2 configurations, V3 crown, and gp41 epitopes. These data highlight the contribution of SP sequence diversity in shaping the Env glycan content and its impact on the configuration and accessibility of V1V2 and other Env epitopes. HIV-1 Env glycoprotein is produced by a precursor gp160 that has a signal peptide at its N-terminus. The SP is highly diverse among the HIV-1 isolates. This study presents site-specific analyses of N-linked glycosylation on HIV-1 envelope glycoproteins from infectious viruses produced with different envelope signal peptides. We show that signal peptide swapping alters the envelope glycan shield, including the conserved N156 and N160 glycans located in the V1V2 region on the trimer apex, to impact Env recognition and virus neutralization by antibodies. The data offer crucial insights into the role of signal peptide in the interplay between HIV-1 and antibodies and its potential utility to control Env glycosylation in the development of Env-based HIV-1 vaccine.
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Probing the Structure of the HIV-1 Envelope Trimer Using Aspartate Scanning Mutagenesis. J Virol 2020; 94:JVI.01426-20. [PMID: 32817217 DOI: 10.1128/jvi.01426-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 08/11/2020] [Indexed: 12/20/2022] Open
Abstract
HIV-1 envelope (Env) glycoprotein gp160 exists as a trimer of heterodimers on the viral surface. In most structures of the soluble ectodomain of trimeric HIV-1 envelope glycoprotein, the regions from 512 to 517 of the fusion peptide and from 547 to 568 of the N-heptad repeat are disordered. We used aspartate scanning mutagenesis of subtype B strain JRFL Env as an alternate method to probe residue burial in the context of cleaved, cell surface-expressed Env, as buried residues should be intolerant to substitution with Asp. The data are inconsistent with a fully disordered 547 to 568 stretch, as residues 548, 549, 550, 555, 556, 559, 562, and 566 to 569 are all sensitive to Asp substitution. In the fusion peptide region, residues 513 and 515 were also sensitive to Asp substitution, suggesting that the fusion peptide may not be fully exposed in native Env. gp41 is metastable in the context of native trimer. Introduction of Asp at residues that are exposed in the prefusion state but buried in the postfusion state is expected to destabilize the postfusion state and any intermediate states where the residue is buried. We therefore performed soluble CD4 (sCD4)-induced gp120 shedding experiments to identify Asp mutants at residues 551, 554 to 559, 561 to 567, and 569 that could prevent gp120 shedding. We also observed similar mutational effects on shedding for equivalent mutants in the context of clade C Env from isolate 4-2J.41. These substitutions can potentially be used to stabilize native-like trimer derivatives that are used as HIV-1 vaccine immunogens.IMPORTANCE In most crystal structures of the soluble ectodomain of the HIV-1 Env trimer, some residues in the fusion and N-heptad repeat regions are disordered. Whether this is true in the context of native, functional Env on the virion surface is not known. This knowledge may be useful for stabilizing Env in its prefusion conformation and will also help to improve understanding of the viral entry process. Burial of the charged residue Asp in a protein structure is highly destabilizing. We therefore used Asp scanning mutagenesis to probe the burial of apparently disordered residues in native Env and to examine the effect of mutations in these regions on Env stability and conformation as probed by antibody binding to cell surface-expressed Env, CD4-induced shedding of HIV-1 gp120, and viral infectivity studies. Mutations that prevent shedding can potentially be used to stabilize native-like Env constructs for use as vaccine immunogens.
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Abstract
PURPOSE OF REVIEW We will discuss recent advances in the development of nanoparticle vaccines presenting HIV-1 envelope trimer vaccines and the immunological mechanisms by which they act. RECENT FINDINGS The multivalent presentation of Env trimers on nanoparticles is a promising strategy to increase Env immunogenicity. Recent studies have shed light on how Env nanoparticles increase lymph node trafficking and germinal center formation by using the lectin-mediated complement pathway and enhancing the interaction with naïve B cells. Meanwhile, research on different nanoparticle platforms has resulted in improved designs, such as liposomes with improved stability, and the emergence of novel platforms such as protein nanoparticles that self-assemble in vitro. Immmunogenicity studies with these nanoparticles delineate the advantages and expose the limitations of the different nanoparticle platforms. SUMMARY It is becoming increasingly clear that HIV-1 vaccine research might benefit greatly from using nanoparticles presenting Env trimers, particularly during the priming stage of immunization. Among the different nanoparticles that are being pursued, in vitro-assembling nanoparticles allow for greater control of Env quality making them a promising nanoparticle platform.
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14
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Abstract
Infected T cells and macrophages are the main producers of HIV-1 in infected individuals. Upon release from infected cells, HIV-1 incorporates various cellular membrane proteins, some of which are specific for these cells. However, the functions of cell-encoded proteins in virions remain largely unknown. We performed flow virometry to identify, in plasma of HIV-infected individuals, macrophage- and T-cell-derived HIV-1 virions, using cell-specific markers CD36 and CD27, respectively. Using four different methods, we demonstrated that CD36 on virions binds the immunosuppressive cytokine transforming growth factor beta (TGF-β) through a ligand, thrombospondin one (TSP-1). Flow virometry of individual virions showed that TGF-β was present on CD36+ virions (average, 28.2% ± 6.6% (n = 3)) but not on CD27+ virions (average, 1% ± 0.1% (n = 3)). TGF-β molecules present on captured CD36+ virions were biologically active, as evaluated with a reporter cell line. Delivery of TGF-β on HIV virions to HIV target cells may affect them, playing a significant role in viral pathogenesis.
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15
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Ringe RP, Colin P, Torres JL, Yasmeen A, Lee WH, Cupo A, Ward AB, Klasse PJ, Moore JP. SOS and IP Modifications Predominantly Affect the Yield but Not Other Properties of SOSIP.664 HIV-1 Env Glycoprotein Trimers. J Virol 2019; 94:e01521-19. [PMID: 31619555 PMCID: PMC6912111 DOI: 10.1128/jvi.01521-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 10/08/2019] [Indexed: 01/20/2023] Open
Abstract
Soluble recombinant native-like (NL) envelope glycoprotein (Env) trimers of various human immunodeficiency virus type 1 (HIV-1) genotypes are being developed as vaccine candidates aimed at the induction of broadly neutralizing antibodies (bNAbs). The prototypic design, designated BG505 SOSIP.664, incorporates an intersubunit disulfide bond (SOS) to covalently link the gp120 and gp41 ectodomain (gp41ECTO) subunits and a point substitution, I559P (IP), to further stabilize the gp41ECTO components. Without the SOS and IP changes, proteolytically cleaved trimers tend to disintegrate into their constituent gp120 and gp41ECTO subunits. We show, however, that NL trimers lacking the SOS and/or IP change can be affinity purified in amounts sufficient for analyses of their antigenicity and thermal stability. In general, these trimer variants have properties highly comparable to those of the fully stabilized SOSIP.664 version. We conclude that the major effect of the SOS and IP changes is to substantially increase trimer stability during and after the expression process, thereby allowing useful amounts to be produced. However, once the trimers have been purified, the SOS and IP changes have only subtle impacts on thermostability and the antigenicity of bNAb and other epitopes.IMPORTANCE Recombinant trimeric proteins based on HIV-1 env genes are being developed for vaccine trials in humans. A feature of these proteins is their mimicry of the envelope glycoprotein structure on virus particles that is targeted by neutralizing antibodies, i.e., antibodies that prevent cells from becoming infected. One vaccine concept under exploration is that recombinant trimers may be able to elicit virus-neutralizing antibodies when delivered as immunogens. A commonly used design is designated SOSIP.664, a term reflecting the sequence changes that are used to stabilize the trimers and allow their production in practically useful amounts. Here, we show that these stabilizing changes act to increase trimer yield during the biosynthesis process within the producer cell but have little impact on the properties of purified trimers.
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Affiliation(s)
- Rajesh P Ringe
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, USA
| | - Philippe Colin
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, USA
| | - Jonathan L Torres
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA
- Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, California, USA
| | - Anila Yasmeen
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, USA
| | - Wen-Hsin Lee
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Albert Cupo
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, USA
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA
- Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, California, USA
- International AIDS Vaccine Initiative (IAVI) Neutralizing Antibody Center and the Collaboration for AIDS Vaccine Discovery (CAVD), The Scripps Research Institute, La Jolla, California, USA
| | - P J Klasse
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, USA
| | - John P Moore
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, USA
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16
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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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17
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Brouwer PJM, Antanasijevic A, Berndsen Z, Yasmeen A, Fiala B, Bijl TPL, Bontjer I, Bale JB, Sheffler W, Allen JD, Schorcht A, Burger JA, Camacho M, Ellis D, Cottrell CA, Behrens AJ, Catalano M, Del Moral-Sánchez I, Ketas TJ, LaBranche C, van Gils MJ, Sliepen K, Stewart LJ, Crispin M, Montefiori DC, Baker D, Moore JP, Klasse PJ, Ward AB, King NP, Sanders RW. Enhancing and shaping the immunogenicity of native-like HIV-1 envelope trimers with a two-component protein nanoparticle. Nat Commun 2019; 10:4272. [PMID: 31537780 PMCID: PMC6753213 DOI: 10.1038/s41467-019-12080-1] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Accepted: 08/16/2019] [Indexed: 12/26/2022] Open
Abstract
The development of native-like HIV-1 envelope (Env) trimer antigens has enabled the induction of neutralizing antibody (NAb) responses against neutralization-resistant HIV-1 strains in animal models. However, NAb responses are relatively weak and narrow in specificity. Displaying antigens in a multivalent fashion on nanoparticles (NPs) is an established strategy to increase their immunogenicity. Here we present the design and characterization of two-component protein NPs displaying 20 stabilized SOSIP trimers from various HIV-1 strains. The two-component nature permits the incorporation of exclusively well-folded, native-like Env trimers into NPs that self-assemble in vitro with high efficiency. Immunization studies show that the NPs are particularly efficacious as priming immunogens, improve the quality of the Ab response over a conventional one-component nanoparticle system, and are most effective when SOSIP trimers with an apex-proximate neutralizing epitope are displayed. Their ability to enhance and shape the immunogenicity of SOSIP trimers make these NPs a promising immunogen platform.
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Affiliation(s)
- Philip J M Brouwer
- Amsterdam UMC, Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, University of Amsterdam, Amsterdam, 1105AZ, The Netherlands
| | - Aleksandar Antanasijevic
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, 92037, USA
| | - Zachary Berndsen
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, 92037, USA
| | - Anila Yasmeen
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, 10065, USA
| | - Brooke Fiala
- Department of Biochemistry, University of Washington, Seattle, Washington, 98195, USA.,Institute for Protein Design, University of Washington, Seattle, Washington, 98195, USA
| | - Tom P L Bijl
- Amsterdam UMC, Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, University of Amsterdam, Amsterdam, 1105AZ, The Netherlands
| | - Ilja Bontjer
- Amsterdam UMC, Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, University of Amsterdam, Amsterdam, 1105AZ, The Netherlands
| | - Jacob B Bale
- Department of Biochemistry, University of Washington, Seattle, Washington, 98195, USA.,Institute for Protein Design, University of Washington, Seattle, Washington, 98195, USA.,Arzeda Corporation, Seattle, Washington, 98119, USA
| | - William Sheffler
- Department of Biochemistry, University of Washington, Seattle, Washington, 98195, USA.,Institute for Protein Design, University of Washington, Seattle, Washington, 98195, USA
| | - Joel D Allen
- Biological Sciences and Institute of Life Sciences, University of Southampton, SO17 1BJ, Southampton, UK
| | - Anna Schorcht
- Amsterdam UMC, Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, University of Amsterdam, Amsterdam, 1105AZ, The Netherlands
| | - Judith A Burger
- Amsterdam UMC, Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, University of Amsterdam, Amsterdam, 1105AZ, The Netherlands
| | - Miguel Camacho
- Amsterdam UMC, Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, University of Amsterdam, Amsterdam, 1105AZ, The Netherlands
| | - Daniel Ellis
- Department of Biochemistry, University of Washington, Seattle, Washington, 98195, USA.,Institute for Protein Design, University of Washington, Seattle, Washington, 98195, USA
| | - Christopher A Cottrell
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, 92037, USA
| | - Anna-Janina Behrens
- Department of Biochemistry, Oxford Glycobiology Institute, University of Oxford, OX1 3QU, Oxford, UK.,New England Biolabs, Inc., Ipswich, Massachussetts, 01938, USA
| | - Marco Catalano
- Amsterdam UMC, Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, University of Amsterdam, Amsterdam, 1105AZ, The Netherlands
| | - Iván Del Moral-Sánchez
- Amsterdam UMC, Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, University of Amsterdam, Amsterdam, 1105AZ, The Netherlands
| | - Thomas J Ketas
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, 10065, USA
| | - Celia LaBranche
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, 27710, USA
| | - Marit J van Gils
- Amsterdam UMC, Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, University of Amsterdam, Amsterdam, 1105AZ, The Netherlands
| | - Kwinten Sliepen
- Amsterdam UMC, Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, University of Amsterdam, Amsterdam, 1105AZ, The Netherlands
| | - Lance J Stewart
- Department of Biochemistry, University of Washington, Seattle, Washington, 98195, USA.,Institute for Protein Design, University of Washington, Seattle, Washington, 98195, USA
| | - Max Crispin
- Biological Sciences and Institute of Life Sciences, University of Southampton, SO17 1BJ, Southampton, UK.,Department of Biochemistry, Oxford Glycobiology Institute, University of Oxford, OX1 3QU, Oxford, UK
| | - David C Montefiori
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, 27710, USA
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, Washington, 98195, USA.,Institute for Protein Design, University of Washington, Seattle, Washington, 98195, USA.,Howard Hughes Medical Institute, University of Washington, Seattle, Washington, 98105, USA
| | - John P Moore
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, 10065, USA
| | - Per Johan Klasse
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, 10065, USA
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, 92037, USA
| | - Neil P King
- Department of Biochemistry, University of Washington, Seattle, Washington, 98195, USA. .,Institute for Protein Design, University of Washington, Seattle, Washington, 98195, USA.
| | - Rogier W Sanders
- Amsterdam UMC, Department of Medical Microbiology, Amsterdam Infection & Immunity Institute, University of Amsterdam, Amsterdam, 1105AZ, The Netherlands.
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18
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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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19
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Conformational Engineering of HIV-1 Env Based on Mutational Tolerance in the CD4 and PG16 Bound States. J Virol 2019; 93:JVI.00219-19. [PMID: 30894475 DOI: 10.1128/jvi.00219-19] [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: 02/07/2019] [Accepted: 03/16/2019] [Indexed: 12/22/2022] Open
Abstract
HIV-1 infection is initiated by viral Env engaging the host receptor CD4, triggering Env to transition from a "closed" to "open" conformation during the early events of virus-cell membrane fusion. To understand how Env sequence accommodates this conformational change, mutational landscapes decoupled from virus replication were determined for Env from BaL (clade B) and DU422 (clade C) isolates interacting with CD4 or antibody PG16 that preferentially recognizes closed trimers. Sequence features uniquely important to each bound state were identified, including glycosylation and binding sites. Notably, the Env apical domain and trimerization interface are under selective pressure for PG16 binding. Based on this key observation, mutations were found that increase presentation of quaternary epitopes associated with properly conformed trimers when Env is expressed at the plasma membrane. Many mutations reduce electrostatic repulsion at the Env apex and increase PG16 recognition of Env sequences from clades A and B. Other mutations increase hydrophobic packing at the gp120 inner-outer domain interface and were broadly applicable for engineering Env from diverse strains spanning tiers 1, 2, and 3 across clades A, B, C, and BC recombinants. Core mutations predicted to introduce steric strain in the open state show markedly reduced CD4 interactions. Finally, we demonstrate how our methodology can be adapted to interrogate interactions between membrane-associated Env and the matrix domain of Gag. These findings and methods may assist vaccine design.IMPORTANCE HIV-1 Env is dynamic and undergoes large conformational changes that drive fusion of virus and host cell membranes. Three Env proteins in a trimer contact each other at their apical tips to form a closed conformation that presents epitopes recognized by broadly neutralizing antibodies. The apical tips separate, among other changes, to form an open conformation that binds tightly to host receptors. Understanding how Env sequence facilitates these structural changes can inform the biophysical mechanism and aid immunogen design. Using deep mutational scans decoupled from virus replication, we report mutational landscapes for Env from two strains interacting with conformation-dependent binding proteins. Residues in the Env trimer interface and apical domains are preferentially conserved in the closed conformation, and conformational diversity is facilitated by electrostatic repulsion and an underpacked core between domains. Specific mutations are described that enhance presentation of the trimeric closed conformation across diverse HIV-1 strains.
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20
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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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21
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Carravilla P, Chojnacki J, Rujas E, Insausti S, Largo E, Waithe D, Apellaniz B, Sicard T, Julien JP, Eggeling C, Nieva JL. Molecular recognition of the native HIV-1 MPER revealed by STED microscopy of single virions. Nat Commun 2019; 10:78. [PMID: 30622256 PMCID: PMC6325134 DOI: 10.1038/s41467-018-07962-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 12/07/2018] [Indexed: 11/09/2022] Open
Abstract
Antibodies against the Membrane-Proximal External Region (MPER) of the Env gp41 subunit neutralize HIV-1 with exceptional breadth and potency. Due to the lack of knowledge on the MPER native structure and accessibility, different and exclusive models have been proposed for the molecular mechanism of MPER recognition by broadly neutralizing antibodies. Here, accessibility of antibodies to the native Env MPER on single virions has been addressed through STED microscopy. STED imaging of fluorescently labeled Fabs reveals a common pattern of native Env recognition for HIV-1 antibodies targeting MPER or the surface subunit gp120. In the case of anti-MPER antibodies, the process evolves with extra contribution of interactions with the viral lipid membrane to binding specificity. Our data provide biophysical insights into the recognition of the potent and broadly neutralizing MPER epitope on HIV virions, and as such is of importance for the design of therapeutic interventions.
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Affiliation(s)
- Pablo Carravilla
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080, Bilbao, Spain
| | - Jakub Chojnacki
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Edurne Rujas
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080, Bilbao, Spain
| | - Sara Insausti
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080, Bilbao, Spain
| | - Eneko Largo
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080, Bilbao, Spain
| | - Dominic Waithe
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Beatriz Apellaniz
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080, Bilbao, Spain
| | - Taylor Sicard
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, ON, M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Jean-Philippe Julien
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, ON, M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
- Department of Immunology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Christian Eggeling
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK.
- Institute of Applied Optics Friedrich-Schiller-University Jena, Max-Wien Platz 4, 07743, Jena, Germany.
- Leibniz Institute of Photonic Technology e.V., Albert-Einstein-Straße 9, 07745, Jena, Germany.
| | - José L Nieva
- Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080, Bilbao, Spain.
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Margolin E, Chapman R, Meyers AE, van Diepen MT, Ximba P, Hermanus T, Crowther C, Weber B, Morris L, Williamson AL, Rybicki EP. Production and Immunogenicity of Soluble Plant-Produced HIV-1 Subtype C Envelope gp140 Immunogens. FRONTIERS IN PLANT SCIENCE 2019; 10:1378. [PMID: 31737007 PMCID: PMC6831737 DOI: 10.3389/fpls.2019.01378] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 10/07/2019] [Indexed: 05/11/2023]
Abstract
The development of effective vaccines is urgently needed to curb the spread of human immunodeficiency virus type 1 (HIV-1). A major focal point of current HIV vaccine research is the production of soluble envelope (Env) glycoproteins which reproduce the structure of the native gp160 trimer. These antigens are produced in mammalian cells, which requires a sophisticated infrastructure for manufacture that is mostly absent in developing countries. The production of recombinant proteins in plants is an attractive alternative for the potentially cheap and scalable production of vaccine antigens, especially for developing countries. In this study, we developed a transient expression system in Nicotiana benthamiana for the production of soluble HIV Env gp140 antigens based on two rationally selected virus isolates (CAP256 SU and Du151). The scalability of the platform was demonstrated and both affinity and size exclusion chromatography (SEC) were explored for recovery of the recombinant antigens. Rabbits immunized with lectin affinity-purified antigens developed high titres of binding antibodies, including against the V1V2 loop region, and neutralizing antibodies against Tier 1 viruses. The removal of aggregated Env species by gel filtration resulted in the elicitation of superior binding and neutralizing antibodies. Furthermore, a heterologous prime-boost regimen employing a recombinant modified vaccinia Ankara (rMVA) vaccine, followed by boosts with the SEC-purified protein, significantly improved the immunogenicity. To our knowledge, this is the first study to assess the immunogenicity of a near-full length plant-derived Env vaccine immunogen.
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Affiliation(s)
- Emmanuel Margolin
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Rosamund Chapman
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Ann E. Meyers
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
- *Correspondence: Ann E. Meyers,
| | - Michiel T. van Diepen
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Phindile Ximba
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Tandile Hermanus
- National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, South Africa
- Faculty of Health Sciences, University of Witwatersrand, Johannesburg, South Africa
| | - Carol Crowther
- National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, South Africa
- Faculty of Health Sciences, University of Witwatersrand, Johannesburg, South Africa
| | - Brandon Weber
- Structural Biology Research Unit, Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, University of Cape Town, Cape Town, South Africa
| | - Lynn Morris
- National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, South Africa
- Faculty of Health Sciences, University of Witwatersrand, Johannesburg, South Africa
| | - Anna-Lise Williamson
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Edward P. Rybicki
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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Common helical V1V2 conformations of HIV-1 Envelope expose the α4β7 binding site on intact virions. Nat Commun 2018; 9:4489. [PMID: 30367034 PMCID: PMC6203816 DOI: 10.1038/s41467-018-06794-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 09/13/2018] [Indexed: 01/10/2023] Open
Abstract
The α4β7 integrin is a non-essential HIV-1 adhesion receptor, bound by the gp120 V1V2 domain, facilitating rapid viral dissemination into gut-associated lymphoid tissues. Antibodies blocking this interaction early in infection can improve disease outcome, and V1V2-targeted antibodies were correlated with moderate efficacy reported from the RV144 HIV-1 vaccine trial. Monoclonal α4β7-blocking antibodies recognise two slightly different helical V2 conformations, and current structural data suggests their binding sites are occluded in prefusion envelope trimers. Here, we report cocrystal structures of two α4β7-blocking antibodies from an infected donor complexed with scaffolded V1V2 or V2 peptides. Both antibodies recognised the same helix-coil V2 conformation as RV144 antibody CH58, identifying a frequently sampled alternative conformation of full-length V1V2. In the context of Envelope, this α-helical form of V1V2 displays highly exposed α4β7-binding sites, potentially providing a functional role for non-native Envelope on virion or infected cell surfaces in HIV-1 dissemination, pathogenesis, and vaccine design. Antibodies blocking the V1V2 domain of HIV Envelope from binding integrin are associated with positive disease outcomes. Here, Wibmer et al. determine the structure of full length V1V2 bound to these antibodies, revealing an alternative fold of V1V2 with exposed integrin-binding sites that functions on non-native Envelope.
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24
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Differential processing of HIV envelope glycans on the virus and soluble recombinant trimer. Nat Commun 2018; 9:3693. [PMID: 30209313 PMCID: PMC6135743 DOI: 10.1038/s41467-018-06121-4] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 08/17/2018] [Indexed: 11/08/2022] Open
Abstract
As the sole target of broadly neutralizing antibodies (bnAbs) to HIV, the envelope glycoprotein (Env) trimer is the focus of vaccination strategies designed to elicit protective bnAbs in humans. Because HIV Env is densely glycosylated with 75–90 N-glycans per trimer, most bnAbs use or accommodate them in their binding epitope, making the glycosylation of recombinant Env a key aspect of HIV vaccine design. Upon analysis of three HIV strains, we here find that site-specific glycosylation of Env from infectious virus closely matches Envs from corresponding recombinant membrane-bound trimers. However, viral Envs differ significantly from recombinant soluble, cleaved (SOSIP) Env trimers, strongly impacting antigenicity. These results provide a benchmark for virus Env glycosylation needed for the design of soluble Env trimers as part of an overall HIV vaccine strategy. HIV envelope (Env) is a potential vaccine antigen and its N-glycans are part of the epitope of broadly neutralizing antibodies. Here, the authors show that glycosylation of Env from infectious virus closely matches Env from recombinant membrane-bound trimers, while it differs significantly from recombinant soluble, cleaved Env trimers.
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Flemming J, Wiesen L, Herschhorn A. Conformation-Dependent Interactions Between HIV-1 Envelope Glycoproteins and Broadly Neutralizing Antibodies. AIDS Res Hum Retroviruses 2018; 34:794-803. [PMID: 29905080 DOI: 10.1089/aid.2018.0102] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
HIV type 1 (HIV-1) envelope glycoproteins (Env) mediate virus entry and are the target of neutralizing antibodies. Binding of the metastable HIV-1 Env trimer to the CD4 receptor triggers structural rearrangements that mediate Env conformational transitions from a closed conformation to a more open state through an intermediate step. Recent studies have revealed new insights on the dynamics, regulation, and molecular mechanisms of Env transitions along the entry pathway. In this study, we provide an overview of the current knowledge on Env conformational dynamics and the relationship between Env conformational states and neutralization selectivity of the broadly neutralizing antibodies that develop in 10%-20% of infected individuals and may provide guidance for the development of an effective HIV-1 vaccine.
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Affiliation(s)
- Juliana Flemming
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Lisa Wiesen
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Alon Herschhorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
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Lertjuthaporn S, Cicala C, Van Ryk D, Liu M, Yolitz J, Wei D, Nawaz F, Doyle A, Horowitch B, Park C, Lu S, Lou Y, Wang S, Pan R, Jiang X, Villinger F, Byrareddy SN, Santangelo PJ, Morris L, Wibmer CK, Biris K, Mason RD, Gorman J, Hiatt J, Martinelli E, Roederer M, Fujikawa D, Gorini G, Franchini G, Arakelyan A, Ansari AA, Pattanapanyasat K, Kong XP, Fauci AS, Arthos J. Select gp120 V2 domain specific antibodies derived from HIV and SIV infection and vaccination inhibit gp120 binding to α4β7. PLoS Pathog 2018; 14:e1007278. [PMID: 30153309 PMCID: PMC6130882 DOI: 10.1371/journal.ppat.1007278] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 09/10/2018] [Accepted: 08/12/2018] [Indexed: 01/16/2023] Open
Abstract
The GI tract is preferentially targeted during acute/early HIV-1 infection. Consequent damage to the gut plays a central role in HIV pathogenesis. The basis for preferential targeting of gut tissues is not well defined. Recombinant proteins and synthetic peptides derived from HIV and SIV gp120 bind directly to integrin α4β7, a gut-homing receptor. Using both cell-surface expressed α4β7 and a soluble α4β7 heterodimer we demonstrate that its specific affinity for gp120 is similar to its affinity for MAdCAM (its natural ligand). The gp120 V2 domain preferentially engages extended forms of α4β7 in a cation -sensitive manner and is inhibited by soluble MAdCAM. Thus, V2 mimics MAdCAM in the way that it binds to α4β7, providing HIV a potential mechanism to discriminate between functionally distinct subsets of lymphocytes, including those with gut-homing potential. Furthermore, α4β7 antagonists developed for the treatment of inflammatory bowel diseases, block V2 binding to α4β7. A 15-amino acid V2 -derived peptide is sufficient to mediate binding to α4β7. It includes the canonical LDV/I α4β7 binding site, a cryptic epitope that lies 7-9 amino acids amino terminal to the LDV/I, and residues K169 and I181. These two residues were identified in a sieve analysis of the RV144 vaccine trial as sites of vaccine -mediated immune pressure. HIV and SIV V2 mAbs elicited by both vaccination and infection that recognize this peptide block V2-α4β7 interactions. These mAbs recognize conformations absent from the β- barrel presented in a stabilized HIV SOSIP gp120/41 trimer. The mimicry of MAdCAM-α4β7 interactions by V2 may influence early events in HIV infection, particularly the rapid seeding of gut tissues, and supports the view that HIV replication in gut tissue is a central feature of HIV pathogenesis.
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Affiliation(s)
- Sakaorat Lertjuthaporn
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
- Department of Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Claudia Cicala
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Donald Van Ryk
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Matthew Liu
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Jason Yolitz
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Danlan Wei
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Fatima Nawaz
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Allison Doyle
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Brooke Horowitch
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Chung Park
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Shan Lu
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Yang Lou
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Shixia Wang
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Ruimin Pan
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY, United States of America
| | - Xunqing Jiang
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY, United States of America
| | - Francois Villinger
- New Iberia Research Center and Department of Biology, University of Louisiana at Lafayette, Lafayette, LA, United States of America
| | - Siddappa N. Byrareddy
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Philip J. Santangelo
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States of America
| | - Lynn Morris
- Center for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Service (NHLS), Johannesburg, South Africa
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Congella, South Africa
| | - Constantinos Kurt Wibmer
- Center for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Service (NHLS), Johannesburg, South Africa
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Kristin Biris
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Rosemarie D. Mason
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Jason Gorman
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Joseph Hiatt
- Microbiology and Immunology, University of California, San Francisco, CA, United States of America
| | - Elena Martinelli
- Center for Biomedical Research, Population Council, New York, NY, United States of America
| | - Mario Roederer
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Dai Fujikawa
- Animal Models and Vaccine Section, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States of America
| | - Giacomo Gorini
- Animal Models and Vaccine Section, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States of America
| | - Genoveffa Franchini
- Animal Models and Vaccine Section, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States of America
| | - Anush Arakelyan
- Section on Intercellular Interactions, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States of America
| | - Aftab A. Ansari
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, United States of America
| | - Kovit Pattanapanyasat
- Department of Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Xiang-Peng Kong
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY, United States of America
| | - Anthony S. Fauci
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - James Arthos
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
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Margolin E, Chapman R, Williamson A, Rybicki EP, Meyers AE. Production of complex viral glycoproteins in plants as vaccine immunogens. PLANT BIOTECHNOLOGY JOURNAL 2018; 16:1531-1545. [PMID: 29890031 PMCID: PMC6097131 DOI: 10.1111/pbi.12963] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/30/2018] [Accepted: 06/05/2018] [Indexed: 05/19/2023]
Abstract
Plant molecular farming offers a cost-effective and scalable approach to the expression of recombinant proteins which has been proposed as an alternative to conventional production platforms for developing countries. In recent years, numerous proofs of concept have established that plants can produce biologically active recombinant proteins and immunologically relevant vaccine antigens that are comparable to those made in conventional expression systems. Driving many of these advances is the remarkable plasticity of the plant proteome which enables extensive engineering of the host cell, as well as the development of improved expression vectors facilitating higher levels of protein production. To date, the only plant-derived viral glycoprotein to be tested in humans is the influenza haemagglutinin which expresses at ~50 mg/kg. However, many other viral glycoproteins that have potential as vaccine immunogens only accumulate at low levels in planta. A critical consideration for the production of many of these proteins in heterologous expression systems is the complexity of post-translational modifications, such as control of folding, glycosylation and disulphide bridging, which is required to reproduce the native glycoprotein structure. In this review, we will address potential shortcomings of plant expression systems and discuss strategies to optimally exploit the technology for the production of immunologically relevant and structurally authentic glycoproteins for use as vaccine immunogens.
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Affiliation(s)
- Emmanuel Margolin
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Institute of Infectious Disease and Molecular MedicineFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | - Ros Chapman
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Institute of Infectious Disease and Molecular MedicineFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
| | - Anna‐Lise Williamson
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Institute of Infectious Disease and Molecular MedicineFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
| | - Edward P. Rybicki
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Institute of Infectious Disease and Molecular MedicineFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | - Ann E. Meyers
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
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Glycoengineering HIV-1 Env creates 'supercharged' and 'hybrid' glycans to increase neutralizing antibody potency, breadth and saturation. PLoS Pathog 2018; 14:e1007024. [PMID: 29718999 PMCID: PMC5951585 DOI: 10.1371/journal.ppat.1007024] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 05/14/2018] [Accepted: 04/11/2018] [Indexed: 02/07/2023] Open
Abstract
The extensive glycosylation of HIV-1 envelope (Env) glycoprotein leaves few glycan-free holes large enough to admit broadly neutralizing antibodies (bnAb). Consequently, most bnAbs must inevitably make some glycan contacts and avoid clashes with others. To investigate how Env glycan maturation regulates HIV sensitivity to bnAbs, we modified HIV-1 pseudovirus (PV) using various glycoengineering (GE) tools. Promoting the maturation of α-2,6 sialic acid (SA) glycan termini increased PV sensitivity to two bnAbs that target the V2 apex and one to the interface between Env surface gp120 and transmembrane gp41 subunits, typically by up to 30-fold. These effects were reversible by incubating PV with neuraminidase. The same bnAbs were unusually potent against PBMC-produced HIV-1, suggesting similar α-2,6 hypersialylated glycan termini may occur naturally. Overexpressing β-galactosyltransferase during PV production replaced complex glycans with hybrid glycans, effectively 'thinning' trimer glycan coverage. This increased PV sensitivity to some bnAbs but ablated sensitivity to one bnAb that depends on complex glycans. Other bnAbs preferred small glycans or galactose termini. For some bnAbs, the effects of GE were strain-specific, suggesting that GE had context-dependent effects on glycan clashes. GE was also able to increase the percent maximum neutralization (i.e. saturation) by some bnAbs. Indeed, some bnAb-resistant strains became highly sensitive with GE—thus uncovering previously unknown bnAb breadth. As might be expected, the activities of bnAbs that recognize glycan-deficient or invariant oligomannose epitopes were largely unaffected by GE. Non-neutralizing antibodies were also unaffected by GE, suggesting that trimers remain compact. Unlike mature bnAbs, germline-reverted bnAbs avoided or were indifferent to glycans, suggesting that glycan contacts are acquired as bnAbs mature. Together, our results suggest that glycovariation can greatly impact neutralization and that knowledge of the optimal Env glycoforms recognized by bnAbs may assist rational vaccine design. Here we engineered various changes in the sizes and shapes of sugars that decorate HIV surface spike proteins and tested the effects of these changes on virus susceptibility to neutralizing antibodies. In so doing, we were able to define the optimal Env-sugars recognized by prototype bnAbs that recognize various canonical epitope clusters on Env spike proteins. Some bnAbs preferred spike proteins decorated with large, complex glycans. Others preferred smaller glycans that improved their access to underlying protein targets. For similar reasons, germline-reverted versions of bnAbs were also generally more effective when the glycans were small. In some cases, bnAbs acquired an ability to bind to sugars as they matured. A comparison of viruses generated in cell lines and primary cells revealed large differences in bnAb sensitivity, raising questions about clinical relevance of cell line-produced virus for checking vaccine responses and, moreover, the use of these cell lines for manufacturing vaccines. Overall, just as car engines may be modified to be supercharged or hybrid for increased power or efficiency, the sugars of HIV coat proteins may also need to be engineered as 'supercharged' and 'hybrid' or otherwise modified in rational vaccine designs to optimize bnAb recognition.
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29
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Doran RC, Tatsuno GP, O’Rourke SM, Yu B, Alexander DL, Mesa KA, Berman PW. Glycan modifications to the gp120 immunogens used in the RV144 vaccine trial improve binding to broadly neutralizing antibodies. PLoS One 2018; 13:e0196370. [PMID: 29689099 PMCID: PMC5916523 DOI: 10.1371/journal.pone.0196370] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 04/11/2018] [Indexed: 02/03/2023] Open
Abstract
To date, the RV144 HIV vaccine trial has been the only study to show that immunization can confer protection from HIV infection. While encouraging, the modest 31.2% (P = 0.04) efficacy achieved in this study left significant room for improvement, and created an incentive to optimize the AIDSVAX B/E vaccine immunogens to increase the level of vaccine efficacy. Since the completion of the RV144 trial, our understanding of the antigenic structure of the HIV envelope protein, gp120, and of the specificity of broadly neutralizing monoclonal antibodies (bN-mAbs) that bind to it, has significantly improved. In particular, we have learned that multiple families of bN-mAbs require specific oligomannose glycans for binding. Both of the monomeric gp120 immunogens (MN- and A244-rgp120) in the AIDSVAX B/E vaccine used in the RV144 trial were enriched for glycans containing high levels of sialic acid, and lacked critical N-linked glycosylation sites required for binding by several families of bN-mAbs. The absence of these epitopes may have contributed to the low level of efficacy achieved in this study. In this report, we describe our efforts to improve the antigenic structure of the rgp120 immunogens used in the vaccine by optimizing glycan-dependent epitopes recognized by multiple bN-mAbs. Our results demonstrated that by shifting the location of one PNGS in A244-rgp120, and by adding two PNGS to MN-rgp120, in conjunction with the production of both proteins in a cell line that favors the incorporation of oligomannose glycans, we could significantly improve the binding by three major families of bN-mAbs. The immunogens described here represent a second generation of gp120-based vaccine immunogens that exhibit potential for use in RV144 follow-up studies.
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Affiliation(s)
- Rachel C. Doran
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, California, United States of America
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California, United States of America
- * E-mail:
| | - Gwen P. Tatsuno
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, California, United States of America
| | - Sara M. O’Rourke
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, California, United States of America
| | - Bin Yu
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, California, United States of America
| | - David L. Alexander
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, California, United States of America
| | - Kathryn A. Mesa
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, California, United States of America
| | - Phillip W. Berman
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, California, United States of America
- Gladstone Institute of Virology & Immunology, San Francisco, California, United States of America
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Alam SM, Aussedat B, Vohra Y, Meyerhoff RR, Cale EM, Walkowicz WE, Radakovich NA, Anasti K, Armand L, Parks R, Sutherland L, Scearce R, Joyce MG, Pancera M, Druz A, Georgiev IS, Von Holle T, Eaton A, Fox C, Reed SG, Louder M, Bailer RT, Morris L, Abdool-Karim SS, Cohen M, Liao HX, Montefiori DC, Park PK, Fernández-Tejada A, Wiehe K, Santra S, Kepler TB, Saunders KO, Sodroski J, Kwong PD, Mascola JR, Bonsignori M, Moody MA, Danishefsky S, Haynes BF. Mimicry of an HIV broadly neutralizing antibody epitope with a synthetic glycopeptide. Sci Transl Med 2017; 9:9/381/eaai7521. [PMID: 28298421 DOI: 10.1126/scitranslmed.aai7521] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 08/18/2016] [Accepted: 01/31/2017] [Indexed: 12/20/2022]
Abstract
A goal for an HIV-1 vaccine is to overcome virus variability by inducing broadly neutralizing antibodies (bnAbs). One key target of bnAbs is the glycan-polypeptide at the base of the envelope (Env) third variable loop (V3). We have designed and synthesized a homogeneous minimal immunogen with high-mannose glycans reflective of a native Env V3-glycan bnAb epitope (Man9-V3). V3-glycan bnAbs bound to Man9-V3 glycopeptide and native-like gp140 trimers with similar affinities. Fluorophore-labeled Man9-V3 glycopeptides bound to bnAb memory B cells and were able to be used to isolate a V3-glycan bnAb from an HIV-1-infected individual. In rhesus macaques, immunization with Man9-V3 induced V3-glycan-targeted antibodies. Thus, the Man9-V3 glycopeptide closely mimics an HIV-1 V3-glycan bnAb epitope and can be used to isolate V3-glycan bnAbs.
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Affiliation(s)
- S Munir Alam
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA.,Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA.,Department of Pathology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Baptiste Aussedat
- Department of Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Yusuf Vohra
- Department of Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - R Ryan Meyerhoff
- 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
| | - Evan M Cale
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - William E Walkowicz
- Department of Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Nathan A Radakovich
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kara Anasti
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Lawrence Armand
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Robert Parks
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Laura Sutherland
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Richard Scearce
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - M Gordon Joyce
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Marie Pancera
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Aliaksandr Druz
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ivelin S Georgiev
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tarra Von Holle
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Amanda Eaton
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Christopher Fox
- Infectious Disease Research Institute, Seattle, WA 98102, USA
| | - Steven G Reed
- Infectious Disease Research Institute, Seattle, WA 98102, USA
| | - Mark Louder
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Robert T Bailer
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lynn Morris
- National Institute for Communicable Diseases, Johannesburg 2131, South Africa.,Center for the AIDS Programme of Research in South Africa, University of KwaZulu-Natal, Durban 4013, South Africa
| | - Salim S Abdool-Karim
- National Institute for Communicable Diseases, Johannesburg 2131, South Africa.,Center for the AIDS Programme of Research in South Africa, University of KwaZulu-Natal, Durban 4013, South Africa
| | - Myron Cohen
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Hua-Xin Liao
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA.,Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - David C Montefiori
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA.,Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA.,Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - Peter K Park
- Department of Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | | | - Kevin Wiehe
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Sampa Santra
- Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Thomas B Kepler
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, 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
| | - Joseph Sodroski
- Dana-Farber Cancer Institute, Harvard Medical School, 450 Brookline Avenue, Boston, MA 02215, USA
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - John R Mascola
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mattia Bonsignori
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA.,Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - M Anthony Moody
- 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.,Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Samuel Danishefsky
- Department of Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Barton F Haynes
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA.,Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA.,Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA
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Vzorov AN, Uryvaev LV. Requirements for the Induction of Broadly Neutralizing Antibodies against HIV-1 by Vaccination. Mol Biol 2017. [DOI: 10.1134/s0026893317060176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Functional Stability of HIV-1 Envelope Trimer Affects Accessibility to Broadly Neutralizing Antibodies at Its Apex. J Virol 2017; 91:JVI.01216-17. [PMID: 28978711 DOI: 10.1128/jvi.01216-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 09/29/2017] [Indexed: 02/07/2023] Open
Abstract
The trimeric envelope glycoprotein spike (Env) of HIV-1 is the target of vaccine development to elicit broadly neutralizing antibodies (bnAbs). Env trimer instability and heterogeneity in principle make subunit interfaces inconsistent targets for the immune response. Here, we investigate how functional stability of Env relates to neutralization sensitivity to V2 bnAbs and V3 crown antibodies that engage subunit interfaces upon binding to unliganded Env. Env heterogeneity was inferred when antibodies neutralized a mutant Env with a plateau of less than 100% neutralization. A statistically significant correlation was found between the stability of mutant Envs and the MPN of V2 bnAb, PG9, as well as an inverse correlation between stability of Env and neutralization by V3 crown antibody, 447-52D. A number of Env-stabilizing mutations and V2 bnAb-enhancing mutations were identified in Env, but they did not always overlap, indicating distinct requirements of functional stabilization versus antibody recognition. Blocking complex glycosylation of Env affected V2 bnAb recognition, as previously described, but also notably increased functional stability of Env. This study shows how instability and heterogeneity affect antibody sensitivity of HIV-1 Env, which is relevant to vaccine design involving its dynamic apex.IMPORTANCE The Env trimer is the only viral protein on the surface of HIV-1 and is the target of neutralizing antibodies that reduce viral infectivity. Quaternary epitopes at the apex of the spike are recognized by some of the most potent and broadly neutralizing antibodies to date. Being that their glycan-protein hybrid epitopes are at subunit interfaces, the resulting heterogeneity can lead to partial neutralization. Here, we screened for mutations in Env that allowed for complete neutralization by the bnAbs. We found that when mutations outside V2 increased V2 bnAb recognition, they often also increased Env stability-of-function and decreased binding by narrowly neutralizing antibodies to the V3 crown. Three mutations together increased neutralization by V2 bnAb and eliminated binding by V3 crown antibodies. These results may aid the design of immunogens that elicit antibodies to the trimer apex.
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Abstract
HIV employs multiple means to evade the humoral immune response, particularly the elicitation of and recognition by broadly neutralizing antibodies (bnAbs). Such antibodies can act antivirally against a wide spectrum of viruses by targeting relatively conserved regions on the surface HIV envelope trimer spike. Elicitation of and recognition by bnAbs are hindered by the arrangement of spikes on virions and the relatively difficult access to bnAb epitopes on spikes, including the proximity of variable regions and a high density of glycans. Yet, in a small proportion of HIV-infected individuals, potent bnAb responses do develop, and isolation of the corresponding monoclonal antibodies has been facilitated by identification of favorable donors with potent bnAb sera and by development of improved methods for human antibody generation. Molecular studies of recombinant Env trimers, alone and in interaction with bnAbs, are providing new insights that are fueling the development and testing of promising immunogens aimed at the elicitation of bnAbs.
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Affiliation(s)
- Dennis R Burton
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California 92037; , .,Neutralizing Antibody Center, International AIDS Vaccine Initiative, The Scripps Research Institute, La Jolla, California 92037.,Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, California 92037.,Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University; Boston, Massachusetts 02142
| | - Lars Hangartner
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California 92037; , .,Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, California 92037
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Virus-like Particles Identify an HIV V1V2 Apex-Binding Neutralizing Antibody that Lacks a Protruding Loop. Immunity 2017; 46:777-791.e10. [PMID: 28514685 DOI: 10.1016/j.immuni.2017.04.011] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 02/09/2017] [Accepted: 04/21/2017] [Indexed: 11/21/2022]
Abstract
Most HIV-1-specific neutralizing antibodies isolated to date exhibit unusual characteristics that complicate their elicitation. Neutralizing antibodies that target the V1V2 apex of the HIV-1 envelope (Env) trimer feature unusually long protruding loops, which enable them to penetrate the HIV-1 glycan shield. As antibodies with loops of requisite length are created through uncommon recombination events, an alternative mode of apex binding has been sought. Here, we isolated a lineage of Env apex-directed neutralizing antibodies, N90-VRC38.01-11, by using virus-like particles and conformationally stabilized Env trimers as B cell probes. A crystal structure of N90-VRC38.01 with a scaffolded V1V2 revealed a binding mode involving side-chain-to-side-chain interactions that reduced the distance the antibody loop must traverse the glycan shield, thereby facilitating V1V2 binding via a non-protruding loop. The N90-VRC38 lineage thus identifies a solution for V1V2-apex binding that provides a more conventional B cell pathway for vaccine design.
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Karlsson Hedestam GB, Guenaga J, Corcoran M, Wyatt RT. Evolution of B cell analysis and Env trimer redesign. Immunol Rev 2017; 275:183-202. [PMID: 28133805 DOI: 10.1111/imr.12515] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
HIV-1 and its surface envelope glycoproteins (Env), gp120 and gp41, have evolved immune evasion strategies that render the elicitation of effective antibody responses to the functional Env entry unit extremely difficult. HIV-1 establishes chronic infection and stimulates vigorous immune responses in the human host; forcing selection of viral variants that escape cellular and antibody (Ab)-mediated immune pressure, yet possess contemporary fitness. Successful survival of fit variants through the gauntlet of the human immune system make this virus and these glycoproteins a formidable challenge to target by vaccination, requiring a systematic approach to Env mimetic immunogen design and evaluation of elicited responses. Here, we review key aspects of HIV-1 Env immunogenicity and immunogen re-design, based on experimental data generated by us and others over the past decade or more. We further provide rationale and details regarding the use of newly evolving tools to analyze B cell responses, including approaches to use next generation sequencing for antibody lineage tracing and B cell fate mapping. Together, these developments offer opportunities to address long-standing questions about the establishment of effective B cell immunity elicited by vaccination, not just against HIV-1.
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Affiliation(s)
| | - Javier Guenaga
- Department of Immunology and Microbial Science, IAVI Neutralizing Antibody Center at TSRI, La Jolla, CA, USA
| | - Martin Corcoran
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Richard T Wyatt
- Department of Immunology and Microbial Science, IAVI Neutralizing Antibody Center at TSRI, La Jolla, CA, USA.,The Scripps CHAVI-ID, La Jolla, CA, USA
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36
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Crooks ET, Osawa K, Tong T, Grimley SL, Dai YD, Whalen RG, Kulp DW, Menis S, Schief WR, Binley JM. Effects of partially dismantling the CD4 binding site glycan fence of HIV-1 Envelope glycoprotein trimers on neutralizing antibody induction. Virology 2017; 505:193-209. [PMID: 28279830 PMCID: PMC5895097 DOI: 10.1016/j.virol.2017.02.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 02/28/2017] [Indexed: 12/31/2022]
Abstract
Previously, VLPs bearing JR-FL strain HIV-1 Envelope trimers elicited potent neutralizing antibodies (nAbs) in 2/8 rabbits (PLoS Pathog 11(5): e1004932) by taking advantage of a naturally absent glycan at position 197 that borders the CD4 binding site (CD4bs). In new immunizations, we attempted to improve nAb responses by removing the N362 glycan that also lines the CD4bs. All 4 rabbits developed nAbs. One targeted the N197 glycan hole like our previous sera. Two sera depended on the N463 glycan, again suggesting CD4bs overlap. Heterologous boosts appeared to reduce nAb clashes with the N362 glycan. The fourth serum targeted a N362 glycan-sensitive epitope. VLP manufacture challenges prevented us from immunizing larger rabbit numbers to empower a robust statistical analysis. Nevertheless, trends suggest that targeted glycan removal may improve nAb induction by exposing new epitopes and that it may be possible to modify nAb specificity using rational heterologous boosts.
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Affiliation(s)
- Ema T Crooks
- San Diego Biomedical Research Institute, 10865 Road to the Cure, San Diego, CA 92121, USA
| | - Keiko Osawa
- San Diego Biomedical Research Institute, 10865 Road to the Cure, San Diego, CA 92121, USA
| | - Tommy Tong
- San Diego Biomedical Research Institute, 10865 Road to the Cure, San Diego, CA 92121, USA
| | - Samantha L Grimley
- San Diego Biomedical Research Institute, 10865 Road to the Cure, San Diego, CA 92121, USA
| | - Yang D Dai
- The Scripps Research Institute, Department of Immunology and Microbial Science, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Robert G Whalen
- Altravax, Inc., 725 San Aleso Avenue, Suite 2, Sunnyvale, CA 94085, USA
| | - Daniel W Kulp
- IAVI Neutralizing Antibody Center at The Scripps Research Institute, Department of Immunology and Microbial Science, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Sergey Menis
- IAVI Neutralizing Antibody Center at The Scripps Research Institute, Department of Immunology and Microbial Science, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - William R Schief
- IAVI Neutralizing Antibody Center at The Scripps Research Institute, Department of Immunology and Microbial Science, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02129, USA
| | - James M Binley
- San Diego Biomedical Research Institute, 10865 Road to the Cure, San Diego, CA 92121, USA.
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38
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Abstract
We describe the development and potential use of various designs of recombinant HIV-1 envelope glycoprotein trimers that mimic the structure of the virion-associated spike, which is the target for neutralizing antibodies. The goal of trimer development programs is to induce broadly neutralizing antibodies with the potential to intervene against multiple circulating HIV-1 strains. Among the topics we address are the designs of various constructs; how native-like trimers can be produced and purified; the properties of such trimers in vitro and their immunogenicity in various animals; and the immunization strategies that may lead to the eventual elicitation of broadly neutralizing antibodies. In summary, native-like trimers are a now a platform for structure- and immunology-based design improvements that could eventually yield immunogens of practical value for solving the long-standing HIV-1 vaccine problem.
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Affiliation(s)
- Rogier W. Sanders
- Department of Microbiology and ImmunologyWeill Medical College of Cornell UniversityNew YorkNYUSA
- Department of Medical MicrobiologyAcademic Medical CenterUniversity of AmsterdamAmsterdamThe Netherlands
| | - John P. Moore
- Department of Microbiology and ImmunologyWeill Medical College of Cornell UniversityNew YorkNYUSA
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Yi HA, Fochtman BC, Rizzo RC, Jacobs A. Inhibition of HIV Entry by Targeting the Envelope Transmembrane Subunit gp41. Curr HIV Res 2016; 14:283-94. [PMID: 26957202 DOI: 10.2174/1570162x14999160224103908] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 09/23/2015] [Accepted: 09/30/2015] [Indexed: 11/22/2022]
Abstract
BACKGROUND The transmembrane subunit of the HIV envelope protein, gp41 is a vulnerable target to inhibit HIV entry. There is one fusion inhibitor T20 (brand name: Fuzeon, generic name: enfuvirtide) available by prescription. However, it has several drawbacks such as a high level of development of drug resistance, a short-half life in vivo, rapid renal clearance, low oral bioavailability, and it is only used as a salvage therapy. Therefore, investigators have been studying a variety of different modalities to attempt to overcome these limitations. METHODS Comprehensive literature searches were performed on HIV gp41, inhibition mechanisms, and inhibitors. The latest structural information was collected, and multiple inhibition strategies targeting gp41 were reviewed. RESULTS Many of the recent advances in inhibitors were peptide-based. Several creative modification strategies have also been performed to improve inhibitory efficacy of peptides and to overcome the drawbacks of T20 treatment. Small compounds have also been an area of intense research. There is a wide variety in development from those identified by virtual screens targeting specific regions of the protein to natural products. Finally, broadly neutralizing antibodies have also been important area of research. The inaccessible nature of the target regions for antibodies is a challenge, however, extensive efforts to develop better neutralizing antibodies are ongoing. CONCLUSION The fusogenic protein, gp41 has been extensively studied as a promising target to inhibit membrane fusion between the virus and target cells. At the same time, it is a challenging target because the vulnerable conformations of the protein are exposed only transiently. However, advances in biochemical, biophysical, structural, and immunological studies are coming together to move the field closer to an understanding of gp41 structure and function that will lead to the development of novel drugs and vaccines.
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Affiliation(s)
| | | | | | - Amy Jacobs
- Department of Microbiology and Immunology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA.
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HIV Envelope gp120 Alters T Cell Receptor Mobilization in the Immunological Synapse of Uninfected CD4 T Cells and Augments T Cell Activation. J Virol 2016; 90:10513-10526. [PMID: 27630246 DOI: 10.1128/jvi.01532-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 09/07/2016] [Indexed: 01/21/2023] Open
Abstract
HIV is transmitted most efficiently from cell to cell, and productive infection occurs mainly in activated CD4 T cells. It is postulated that HIV exploits immunological synapses formed between CD4 T cells and antigen-presenting cells to facilitate the targeting and infection of activated CD4 T cells. This study sought to evaluate how the presence of the HIV envelope (Env) in the CD4 T cell immunological synapse affects synapse formation and intracellular signaling to impact the downstream T cell activation events. CD4 T cells were applied to supported lipid bilayers that were reconstituted with HIV Env gp120, anti-T cell receptor (anti-TCR) monoclonal antibody, and ICAM-1 to represent the surface of HIV Env-bearing antigen-presenting cells. The results showed that the HIV Env did not disrupt immunological synapse formation. Instead, the HIV Env accumulated with TCR at the center of the synapse, altered the kinetics of TCR recruitment to the synapse and affected synapse morphology over time. The HIV Env also prolonged Lck phosphorylation at the synapse and enhanced TCR-induced CD69 upregulation, interleukin-2 secretion, and proliferation to promote virus infection. These results suggest that HIV uses the immunological synapse as a conduit not only for selective virus transmission to activated CD4 T cells but also for boosting the T cell activation state, thereby increasing its likelihood of undergoing productive replication in targeted CD4 T cells. IMPORTANCE There are about two million new HIV infections every year. A better understanding of how HIV is transmitted to susceptible cells is critical to devise effective strategies to prevent HIV infection. Activated CD4 T cells are preferentially infected by HIV, although how this is accomplished is not fully understood. This study examined whether HIV co-opts the normal T cell activation process through the so-called immunological synapse. We found that the HIV envelope is recruited to the center of the immunological synapse together with the T cell receptor and enhances the T cell receptor-induced activation of CD4 T cells. Heightened cellular activation promotes the capacity of CD4 T cells to support productive HIV replication. This study provides evidence of the exploitation of the normal immunological synapse and T cell activation process by HIV to boost the activation state of targeted CD4 T cells and promote the infection of these cells.
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Kalyana Sundaram RV, Li H, Bailey L, Rashad AA, Aneja R, Weiss K, Huynh J, Bastian AR, Papazoglou E, Abrams C, Wrenn S, Chaiken I. Impact of HIV-1 Membrane Cholesterol on Cell-Independent Lytic Inactivation and Cellular Infectivity. Biochemistry 2016; 55:447-58. [PMID: 26713837 DOI: 10.1021/acs.biochem.5b00936] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Peptide triazole thiols (PTTs) have been found previously to bind to HIV-1 Env spike gp120 and cause irreversible virus inactivation by shedding gp120 and lytically releasing luminal capsid protein p24. Since the virions remain visually intact, lysis appears to occur via limited membrane destabilization. To better understand the PTT-triggered membrane transformation involved, we investigated the role of envelope cholesterol on p24 release by measuring the effect of cholesterol depletion using methyl beta-cyclodextrin (MβCD). An unexpected bell-shaped response of PTT-induced lysis to [MβCD] was observed, involving lysis enhancement at low [MβCD] vs loss of function at high [MβCD]. The impact of cholesterol depletion on PTT-induced lysis was reversed by adding exogenous cholesterol and other sterols that support membrane rafts, while sterols that do not support rafts induced only limited reversal. Cholesterol depletion appears to cause a reduced energy barrier to lysis as judged by decreased temperature dependence with MβCD. Enhancement/replenishment responses to [MβCD] also were observed for HIV-1 infectivity, consistent with a similar energy barrier effect in the membrane transformation of virus cell fusion. Overall, the results argue that cholesterol in the HIV-1 envelope is important for balancing virus stability and membrane transformation, and that partial depletion, while increasing infectivity, also makes the virus more fragile. The results also reinforce the argument that the lytic inactivation and infectivity processes are mechanistically related and that membrane transformations occurring during lysis can provide an experimental window to investigate membrane and protein factors important for HIV-1 cell entry.
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Affiliation(s)
- Ramalingam Venkat Kalyana Sundaram
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine , Philadelphia, Pennsylvania 19102, United States.,School of Biomedical Engineering, Science and Health Systems, Drexel University , Philadelphia, Pennsylvania 19104, United States
| | - Huiyuan Li
- Shared Research Facilities, West Virginia University , Morgantown, West Virginia 26506, United States
| | - Lauren Bailey
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine , Philadelphia, Pennsylvania 19102, United States
| | - Adel A Rashad
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine , Philadelphia, Pennsylvania 19102, United States
| | - Rachna Aneja
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine , Philadelphia, Pennsylvania 19102, United States
| | - Karl Weiss
- Department of Chemical and Biological Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States
| | - James Huynh
- Department of Biological Sciences, Drexel University , Philadelphia, Pennsylvania 19104, United States
| | - Arangaserry Rosemary Bastian
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine , Philadelphia, Pennsylvania 19102, United States.,School of Biomedical Engineering, Science and Health Systems, Drexel University , Philadelphia, Pennsylvania 19104, United States
| | - Elisabeth Papazoglou
- School of Biomedical Engineering, Science and Health Systems, Drexel University , Philadelphia, Pennsylvania 19104, United States
| | - Cameron Abrams
- Department of Chemical and Biological Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States
| | - Steven Wrenn
- Department of Chemical and Biological Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States
| | - Irwin Chaiken
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine , Philadelphia, Pennsylvania 19102, United States
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Native Conformation and Canonical Disulfide Bond Formation Are Interlinked Properties of HIV-1 Env Glycoproteins. J Virol 2015; 90:2884-94. [PMID: 26719247 DOI: 10.1128/jvi.01953-15] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 12/21/2015] [Indexed: 01/20/2023] Open
Abstract
UNLABELLED We investigated whether there is any association between a native-like conformation and the presence of only the canonical (i.e., native) disulfide bonds in the gp120 subunits of a soluble recombinant human immunodeficiency virus type 1 (HIV-1) envelope (Env) glycoprotein. We used a mass spectrometry (MS)-based method to map the disulfide bonds present in nonnative uncleaved gp140 proteins and native-like SOSIP.664 trimers based on the BG505 env gene. Our results show that uncleaved gp140 proteins were not homogeneous, in that substantial subpopulations (20 to 80%) contained aberrant disulfide bonds. In contrast, the gp120 subunits of the native-like SOSIP.664 trimer almost exclusively retained the canonical disulfide bond pattern. We also observed that the purification method could influence the proportion of an Env protein population that contained aberrant disulfide bonds. We infer that gp140 proteins may always contain a variable but substantial proportion of aberrant disulfide bonds but that the impact of this problem can be minimized via design and/or purification strategies that yield native-like trimers. The same factors may also be relevant to the production and purification of monomeric gp120 proteins that are free of aberrant disulfide bonds. IMPORTANCE It is widely thought that a successful HIV-1 vaccine will include a recombinant form of the Env protein, a trimer located on the virion surface. To increase yield and simplify purification, Env proteins are often made in truncated, soluble forms. A consequence, however, can be the loss of the native conformation concomitant with the virion-associated trimer. Moreover, some soluble recombinant Env proteins contain aberrant disulfide bonds that are not expected to be present in the native trimer. To assess whether these observations are linked, to determine the extent of disulfide bond scrambling, and to understand why scrambling occurs, we determined the disulfide bond profiles of two soluble Env proteins with different designs that are being assessed as vaccine candidates. We found that uncleaved gp140 forms heterogeneous mixtures in which aberrant disulfide bonds abound. In contrast, BG505 SOSIP.664 trimers are more homogeneous, native-like entities that contain predominantly the native disulfide bond profile.
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Sadanand S, Suscovich TJ, Alter G. Broadly Neutralizing Antibodies Against HIV: New Insights to Inform Vaccine Design. Annu Rev Med 2015; 67:185-200. [PMID: 26565674 DOI: 10.1146/annurev-med-091014-090749] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
HIV-1 poses immense immunological challenges to the humoral immune response because of its ability to shield itself and replicate and evolve rapidly. Although most currently licensed vaccines provide protection via the induction of antibodies (Abs) that can directly block infection ( 1 ), 30 years of HIV-1 vaccine research has failed to successfully elicit such Abs against globally relevant HIV strains. However, mounting evidence suggests that these broadly neutralizing antibodies (bNAbs) do emerge naturally in a significant fraction of infected subjects, albeit after years of infection, indicating that these responses can be selected naturally by the immune response but take long periods of time to evolve. We review the basic structural characteristics of broadly neutralizing antibodies and how they recognize the virus, and we discuss new vaccination strategies that aim to mimic natural evolution to guide B cells to produce protective Abs against HIV-1.
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Affiliation(s)
- Saheli Sadanand
- Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts 02139-3583; , ,
| | - Todd J Suscovich
- Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts 02139-3583; , ,
| | - Galit Alter
- Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts 02139-3583; , ,
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Brandenberg OF, Magnus C, Regoes RR, Trkola A. The HIV-1 Entry Process: A Stoichiometric View. Trends Microbiol 2015; 23:763-774. [PMID: 26541228 DOI: 10.1016/j.tim.2015.09.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 08/31/2015] [Accepted: 09/16/2015] [Indexed: 11/15/2022]
Abstract
HIV-1 infection starts with fusion of the viral and the host cell membranes, a process mediated by the HIV-1 envelope glycoprotein trimer. The number of trimers required to complete membrane fusion, referred to as HIV-1 entry stoichiometry, remains under debate. A precise definition of HIV-1 entry stoichiometry is important as it reflects the efficacy of the viral entry process and steers the infectivity of HIV-1 virion populations. Initial estimates suggested a unanimous entry stoichiometry across HIV-1 strains while recent findings showed that HIV-1 strains can differ in entry stoichiometry. Here, we review current analyses of HIV-1 entry stoichiometry and point out future research directions to further define the interplay between entry stoichiometry, virus entry fitness, transmission, and susceptibility to antibody neutralization.
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Affiliation(s)
- Oliver F Brandenberg
- Institute of Medical Virology, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland; Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Carsten Magnus
- Institute of Medical Virology, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Roland R Regoes
- Institute of Integrative Biology, ETH Zürich, Universitätsstrasse 16, CH-8092 Zürich, Switzerland
| | - Alexandra Trkola
- Institute of Medical Virology, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
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Chemical Cross-Linking Stabilizes Native-Like HIV-1 Envelope Glycoprotein Trimer Antigens. J Virol 2015; 90:813-28. [PMID: 26512083 PMCID: PMC4702668 DOI: 10.1128/jvi.01942-15] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/21/2015] [Indexed: 01/26/2023] Open
Abstract
Major neutralizing antibody immune evasion strategies of the HIV-1 envelope glycoprotein (Env) trimer include conformational and structural instability. Stabilized soluble trimers such as BG505 SOSIP.664 mimic the structure of virion-associated Env but nevertheless sample different conformational states. Here we demonstrate that treating BG505 SOSIP.664 trimers with glutaraldehyde or a heterobifunctional cross-linker introduces additional stability with relatively modest effects on antigenicity. Thus, most broadly neutralizing antibody (bNAb) epitopes were preserved after cross-linking, whereas the binding of most weakly or nonneutralizing antibodies (non-NAb) was reduced. Cross-linking stabilized all Env conformers present within a mixed population, and individual conformers could be isolated by bNAb affinity chromatography. Both positive selection of cross-linked conformers using the quaternary epitope-specific bNAbs PGT145, PGT151, and 3BC315 and negative selection with non-NAbs against the V3 region enriched for trimer populations with improved antigenicity for bNAbs. Similar results were obtained using the clade B B41 SOSIP.664 trimer. The cross-linking method may, therefore, be useful for countering the natural conformational heterogeneity of some HIV-1 Env proteins and, by extrapolation, also vaccine immunogens from other pathogens. IMPORTANCE The development of a vaccine to induce protective antibodies against HIV-1 is of primary public health importance. Recent advances in immunogen design have provided soluble recombinant envelope glycoprotein trimers with near-native morphology and antigenicity. However, these trimers are conformationally flexible, potentially reducing B-cell recognition of neutralizing antibody epitopes. Here we show that chemical cross-linking increases trimer stability, reducing binding of nonneutralizing antibodies while largely maintaining neutralizing antibody binding. Cross-linking followed by positive or negative antibody affinity selection of individual stable conformational variants further improved the antigenic and morphological characteristics of the trimers. This approach may be generally applicable to HIV-1 Env and also to other conformationally flexible pathogen antigens.
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Stieh DJ, King DF, Klein K, Aldon Y, McKay PF, Shattock RJ. Discrete partitioning of HIV-1 Env forms revealed by viral capture. Retrovirology 2015; 12:81. [PMID: 26399966 PMCID: PMC4581120 DOI: 10.1186/s12977-015-0207-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 09/15/2015] [Indexed: 11/25/2022] Open
Abstract
Background The structure of HIV-1 envelope glycoprotein (Env) is flexible and heterogeneous on whole virions. Although functional Env complexes are thought to require trimerization of cleaved gp41/gp120 heterodimers, variable processing can result in the potential incorporation of non-functional uncleaved proteins (gp160), non-trimeric arrangements of gp41/gp120 heterodimers, and gp120 depleted gp41 stumps. The potential distribution of functional and non-functional Env forms across replication-competent viral populations may have important implications for neutralizing and non-neutralizing antibody functions. This study applied an immuno-bead viral capture assay (VCA) to interrogate the potential distribution (heterologous vs homologous) of functional and non-functional forms of virion associated Env. Results The VCA revealed a significant association between depletion of infectious virions and virion Env incorporation, but not between infectivity and p24-gag. Three distinct subpopulations of virions were identified within pools of genetically homogenous viral particles. Critically, a significant subpopulation of infectious virions were exclusively captured by neutralizing antibodies (nAbs) indicative of a homologous distribution of functional trimeric Env forms. A second infectious subpopulation bound both neutralizing and non-neutralizing antibodies (nnAbs) representative of a heterologous distribution of Env forms, while a third non-infectious subpopulation was predominantly bound by nnAbs recognizing gp41 stumps. Conclusions The observation that a distinct and significant subpopulation of infectious virions is exclusively captured by neutralizing antibodies has important implications for understanding antibody binding and neutralization, as well as other antibody effector functions. Electronic supplementary material The online version of this article (doi:10.1186/s12977-015-0207-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daniel J Stieh
- Department of Cellular and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
| | - Deborah F King
- Mucosal Infection and Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
| | - Katja Klein
- Mucosal Infection and Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
| | - Yoann Aldon
- Mucosal Infection and Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
| | - Paul F McKay
- Mucosal Infection and Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
| | - Robin J Shattock
- Mucosal Infection and Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
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Burton DR, Mascola JR. Antibody responses to envelope glycoproteins in HIV-1 infection. Nat Immunol 2015; 16:571-6. [PMID: 25988889 DOI: 10.1038/ni.3158] [Citation(s) in RCA: 317] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 03/26/2015] [Indexed: 02/08/2023]
Abstract
Antibody responses to the HIV-1 envelope glycoproteins can be classified into three groups. Binding but non-neutralizing responses are directed to epitopes that are expressed on isolated envelope glycoproteins but not on the native envelope trimer found on the surface of virions and responsible for mediating the entry of virus into target cells. Strain-specific responses and broadly neutralizing responses, in contrast, target epitopes that are expressed on the native trimer, as revealed by recently resolved structures. The past few years have seen the isolation of many broadly neutralizing antibodies of remarkable potency that have shown prophylactic and therapeutic activities in animal models. These antibodies are helping to guide rational vaccine design and therapeutic strategies for HIV-1.
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Affiliation(s)
- Dennis R Burton
- 1] Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, USA. [2] International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, California, USA. [3] Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, California, USA. [4] Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard University, Boston, Massachusetts, USA
| | - John R Mascola
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
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Kwon YD, Pancera M, Acharya P, Georgiev IS, Crooks ET, Gorman J, Joyce MG, Guttman M, Ma X, Narpala S, Soto C, Terry DS, Yang Y, Zhou T, Ahlsen G, Bailer RT, Chambers M, Chuang GY, Doria-Rose NA, Druz A, Hallen MA, Harned A, Kirys T, Louder MK, O'Dell S, Ofek G, Osawa K, Prabhakaran M, Sastry M, Stewart-Jones GBE, Stuckey J, Thomas PV, Tittley T, Williams C, Zhang B, Zhao H, Zhou Z, Donald BR, Lee LK, Zolla-Pazner S, Baxa U, Schön A, Freire E, Shapiro L, Lee KK, Arthos J, Munro JB, Blanchard SC, Mothes W, Binley JM, McDermott AB, Mascola JR, Kwong PD. Crystal structure, conformational fixation and entry-related interactions of mature ligand-free HIV-1 Env. Nat Struct Mol Biol 2015; 22:522-31. [PMID: 26098315 PMCID: PMC4706170 DOI: 10.1038/nsmb.3051] [Citation(s) in RCA: 290] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 05/29/2015] [Indexed: 12/19/2022]
Abstract
As the sole viral antigen on the HIV-1-virion surface, trimeric Env is a focus of vaccine efforts. Here we present the structure of the ligand-free HIV-1-Env trimer, fix its conformation and determine its receptor interactions. Epitope analyses revealed trimeric ligand-free Env to be structurally compatible with broadly neutralizing antibodies but not poorly neutralizing ones. We coupled these compatibility considerations with binding antigenicity to engineer conformationally fixed Envs, including a 201C 433C (DS) variant specifically recognized by broadly neutralizing antibodies. DS-Env retained nanomolar affinity for the CD4 receptor, with which it formed an asymmetric intermediate: a closed trimer bound by a single CD4 without the typical antigenic hallmarks of CD4 induction. Antigenicity-guided structural design can thus be used both to delineate mechanism and to fix conformation, with DS-Env trimers in virus-like-particle and soluble formats providing a new generation of vaccine antigens.
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Affiliation(s)
- Young Do Kwon
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Marie Pancera
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Priyamvada Acharya
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Ivelin S Georgiev
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Emma T Crooks
- San Diego Biomedical Research Institute, San Diego, California, USA
| | - Jason Gorman
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - M Gordon Joyce
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Miklos Guttman
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, USA
| | - Xiaochu Ma
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Sandeep Narpala
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Cinque Soto
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Daniel S Terry
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Yongping Yang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Tongqing Zhou
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Goran Ahlsen
- 1] Department of Biochemistry &Molecular Biophysics, Columbia University, New York, New York, USA. [2] Department of Systems Biology, Columbia University, New York, New York, USA
| | - Robert T Bailer
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Michael Chambers
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Gwo-Yu Chuang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Nicole A Doria-Rose
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Aliaksandr Druz
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Mark A Hallen
- 1] Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA. [2] Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA
| | - Adam Harned
- Electron Microscopy Laboratory, Cancer Research Technology Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Tatsiana Kirys
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Mark K Louder
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Sijy O'Dell
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Gilad Ofek
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Keiko Osawa
- San Diego Biomedical Research Institute, San Diego, California, USA
| | - Madhu Prabhakaran
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Mallika Sastry
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Guillaume B E Stewart-Jones
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Jonathan Stuckey
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Paul V Thomas
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Tishina Tittley
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | | | - Baoshan Zhang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Hong Zhao
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Zhou Zhou
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Bruce R Donald
- 1] Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA. [2] Department of Chemistry, Duke University, Durham, North Carolina, USA. [3] Department of Computer Science, Duke University, Durham, North Carolina, USA
| | - Lawrence K Lee
- Structural and Computational Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia
| | - Susan Zolla-Pazner
- 1] New York University School of Medicine, New York, New York, USA. [2] New York Veterans Affairs Harbor Healthcare System, New York, New York, USA
| | - Ulrich Baxa
- Electron Microscopy Laboratory, Cancer Research Technology Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Arne Schön
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Ernesto Freire
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Lawrence Shapiro
- 1] Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA. [2] Department of Biochemistry &Molecular Biophysics, Columbia University, New York, New York, USA
| | - Kelly K Lee
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, USA
| | - James Arthos
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - James B Munro
- 1] Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA. [2] Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Scott C Blanchard
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, New York, USA
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - James M Binley
- San Diego Biomedical Research Institute, San Diego, California, USA
| | - Adrian B McDermott
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - John R Mascola
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
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Cell- and Protein-Directed Glycosylation of Native Cleaved HIV-1 Envelope. J Virol 2015; 89:8932-44. [PMID: 26085151 DOI: 10.1128/jvi.01190-15] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 06/08/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The gp120/gp41 HIV-1 envelope glycoprotein (Env) is highly glycosylated, with up to 50% of its mass consisting of N-linked glycans. This dense carbohydrate coat has emerged as a promising vaccine target, with its glycans acting as epitopes for a number of potent and broadly neutralizing antibodies (bnAbs). Characterizing the glycan structures present on native HIV-1 Env is thus a critical goal for the design of Env immunogens. In this study, we used a complementary, multistep approach involving ion mobility mass spectrometry and high-performance liquid chromatography to comprehensively characterize the glycan structures present on HIV-1 gp120 produced in peripheral blood mononuclear cells (PBMCs). The capacity of different expression systems, including pseudoviral particles and recombinant cell surface trimers, to reproduce native-like glycosylation was then assessed. A population of oligomannose glycans on gp120 was reproduced across all expression systems, supporting this as an intrinsic property of Env that can be targeted for vaccine design. In contrast, Env produced in HEK 293T cells failed to accurately reproduce the highly processed complex-type glycan structures observed on PBMC-derived gp120, and in particular the precise linkage of sialic acid residues that cap these glycans. Finally, we show that unlike for gp120, the glycans decorating gp41 are mostly complex-type sugars, consistent with the glycan specificity of bnAbs that target this region. These findings provide insights into the glycosylation of native and recombinant HIV-1 Env and can be used to inform strategies for immunogen design and preparation. IMPORTANCE Development of an HIV vaccine is desperately needed to control new infections, and elicitation of HIV bnAbs will likely be an important component of an effective vaccine. Increasingly, HIV bnAbs are being identified that bind to the N-linked glycans coating the HIV envelope glycoproteins gp120 and gp41, highlighting them as important targets for vaccine design. It is therefore important to characterize the glycan structures present on native, virion-associated gp120 and gp41 for development of vaccines that accurately mimic native-Env glycosylation. In this study, we used a number of analytical techniques to precisely study the structures of both the oligomannose and complex-type glycans present on native Env to provide a reference for determining the ability of potential HIV immunogens to accurately replicate the glycosylation pattern on these native structures.
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50
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Pritchard LK, Vasiljevic S, Ozorowski G, Seabright GE, Cupo A, Ringe R, Kim HJ, Sanders RW, Doores KJ, Burton DR, Wilson IA, Ward AB, Moore JP, Crispin M. Structural Constraints Determine the Glycosylation of HIV-1 Envelope Trimers. Cell Rep 2015; 11:1604-13. [PMID: 26051934 DOI: 10.1016/j.celrep.2015.05.017] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 04/23/2015] [Accepted: 05/11/2015] [Indexed: 10/23/2022] Open
Abstract
A highly glycosylated, trimeric envelope glycoprotein (Env) mediates HIV-1 cell entry. The high density and heterogeneity of the glycans shield Env from recognition by the immune system, but paradoxically, many potent broadly neutralizing antibodies (bNAbs) recognize epitopes involving this glycan shield. To better understand Env glycosylation and its role in bNAb recognition, we characterized a soluble, cleaved recombinant trimer (BG505 SOSIP.664) that is a close structural and antigenic mimic of native Env. Large, unprocessed oligomannose-type structures (Man8-9GlcNAc2) are notably prevalent on the gp120 components of the trimer, irrespective of the mammalian cell expression system or the bNAb used for affinity purification. In contrast, gp41 subunits carry more highly processed glycans. The glycans on uncleaved, non-native oligomeric gp140 proteins are also highly processed. A homogeneous, oligomannose-dominated glycan profile is therefore a hallmark of a native Env conformation and a potential Achilles' heel that can be exploited for bNAb recognition and vaccine design.
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Affiliation(s)
- Laura K Pritchard
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Snezana Vasiljevic
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Gabriel Ozorowski
- Department of Integrative Structural and Computational Biology, IAVI Neutralizing Antibody Center and the collaboration for AIDS Vaccine Discovery, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Gemma E Seabright
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Albert Cupo
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, NY 10021, USA
| | - Rajesh Ringe
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, NY 10021, USA
| | - Helen J Kim
- Department of Integrative Structural and Computational Biology, IAVI Neutralizing Antibody Center and the collaboration for AIDS Vaccine Discovery, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Rogier W Sanders
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, NY 10021, USA; Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center of the University of Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Katie J Doores
- King's College London School of Medicine at Guy's, King's and St. Thomas' Hospitals, Guy's Hospital, Great Maze Pond, London SE1 9RT, UK
| | - Dennis R Burton
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA; Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, CA 92037, USA; Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Boston, MA 02142, USA
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, IAVI Neutralizing Antibody Center and the collaboration for AIDS Vaccine Discovery, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, IAVI Neutralizing Antibody Center and the collaboration for AIDS Vaccine Discovery, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - John P Moore
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, NY 10021, USA
| | - Max Crispin
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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