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Jeffy J, Parthasarathy D, Ahmed S, Cervera-Benet H, Xiong U, Harris M, Mazurov D, Pickthorn S, Herschhorn A. Alternative substitutions of N332 in HIV-1 AD8 gp120 differentially affect envelope glycoprotein function and viral sensitivity to broadly neutralizing antibodies targeting the V3-glycan. mBio 2024; 15:e0268623. [PMID: 38470051 PMCID: PMC11005340 DOI: 10.1128/mbio.02686-23] [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: 11/15/2023] [Accepted: 02/20/2024] [Indexed: 03/13/2024] Open
Abstract
The envelope glycoprotein (Env) trimer on the surface of human immunodeficiency virus type I (HIV-1) mediates viral entry into host CD4+ T cells and is the sole target of neutralizing antibodies. Broadly neutralizing antibodies (bnAbs) that target gp120 V3-glycan of HIV-1 Env trimer are potent and block the entry of diverse HIV-1 strains. Most V3-glycan bnAbs interact, to a different extent, with a glycan attached to N332, but Asn at this position is not absolutely conserved or required for HIV-1 entry based on the prevalence of N332 in different circulating HIV-1 strains from diverse clades. Here, we studied the effects of amino acid changes at position 332 of HIV-1AD8 Envs on HIV-1 sensitivity to antibodies, cold exposure, and soluble CD4. We further investigated how these changes affect Env function and HIV-1 infectivity in vitro. Our results suggest robust tolerability of HIV-1AD8 Env N332 to changes, with specific changes that resulted in extended exposure of gp120 V3 loop, which is typically concealed in most primary HIV-1 isolates. Viral evolution leading to Asn at position 332 of HIVAD8 Envs is supported by the selection advantage of high levels of cell-cell fusion, transmission, and infectivity with high levels of cell surface expression and slightly higher gp120 shedding than most N332 variants. Thus, tolerance of HIV-1AD8 Envs to different amino acids at position 332 provides increased flexibility to respond to changing conditions/environments and evade the immune system. Modeling studies of the distance between N332 glycan and specific bnAbs were in agreement with N332 glycan dependency on bnAb neutralization. Overall, our studies provide insights into the contribution of specific amino acids at position 332 to Env antigenicity, stability on ice, and conformational states. IMPORTANCE Glycan attached to amino acid asparagine at position 332 of HIV-1 envelope glycoproteins is a main target of a subset of broadly neutralizing antibodies that block HIV-1 infection. Here, we defined the contribution of different amino acids at this position to Env antigenicity, stability on ice, and conformational states.
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Affiliation(s)
- Jeffy Jeffy
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Durgadevi Parthasarathy
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Shamim Ahmed
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Héctor Cervera-Benet
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Ulahn Xiong
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Miranda Harris
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Dmitriy Mazurov
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Stephanie Pickthorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Alon Herschhorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, USA
- Institute for Engineering in Medicine, University of Minnesota, Minneapolis, Minnesota, USA
- Center of Genomic Engineering, University of Minnesota, Minneapolis, Minnesota, USA
- Microbiology, Immunology, and Cancer Biology Graduate Program, University of Minnesota, Minneapolis, Minnesota, USA
- The College of Veterinary Medicine Graduate Program, University of Minnesota, Minneapolis, Minnesota, USA
- Molecular Pharmacology and Therapeutics Graduate Program, University of Minnesota, Minneapolis, Minnesota, USA
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2
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Misra M, Jeffy J, Liao C, Pickthorn S, Wagh K, Herschhorn A. HIResist: a database of HIV-1 resistance to broadly neutralizing antibodies. Bioinformatics 2024; 40:btae103. [PMID: 38426331 PMCID: PMC10919947 DOI: 10.1093/bioinformatics/btae103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 01/14/2024] [Accepted: 02/27/2024] [Indexed: 03/02/2024] Open
Abstract
MOTIVATION Changing the course of the human immunodeficiency virus type I (HIV-1) pandemic is a high public health priority with approximately 39 million people currently living with HIV-1 (PLWH) and about 1.5 million new infections annually worldwide. Broadly neutralizing antibodies (bnAbs) typically target highly conserved sites on the HIV-1 envelope glycoproteins (Envs), which mediate viral entry, and block the infection of diverse HIV-1 strains. But different mechanisms of HIV-1 resistance to bnAbs prevent robust application of bnAbs for therapeutic and preventive interventions. RESULTS Here we report the development of a new database that provides data and computational tools to aid the discovery of resistant features and may assist in analysis of HIV-1 resistance to bnAbs. Bioinformatic tools allow identification of specific patterns in Env sequences of resistant strains and development of strategies to elucidate the mechanisms of HIV-1 escape; comparison of resistant and sensitive HIV-1 strains for each bnAb; identification of resistance and sensitivity signatures associated with specific bnAbs or groups of bnAbs; and visualization of antibody pairs on cross-sensitivity plots. The database has been designed with a particular focus on user-friendly and interactive interface. Our database is a valuable resource for the scientific community and provides opportunities to investigate patterns of HIV-1 resistance and to develop new approaches aimed to overcome HIV-1 resistance to bnAbs. AVAILABILITY AND IMPLEMENTATION HIResist is freely available at https://hiresist.ahc.umn.edu/.
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Affiliation(s)
- Milind Misra
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, United States
| | - Jeffy Jeffy
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, United States
| | - Charis Liao
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, United States
| | - Stephanie Pickthorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, United States
| | - Kshitij Wagh
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, United States
| | - Alon Herschhorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, United States
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, United States
- Institute for Engineering in Medicine, University of Minnesota, Minneapolis, MN 55455, United States
- Center for Genome Engineering, University of Minnesota, Minneapolis, MN 55455, United States
- Microbiology, Immunology, and Cancer Biology Graduate Program, University of Minnesota, Minneapolis, MN 55455, United States
- The College of Veterinary Medicine Graduate Program, University of Minnesota, Minneapolis, MN 55455, United States
- Molecular Pharmacology and Therapeutics Graduate Program, University of Minnesota, Minneapolis, MN 55455, United States
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3
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Mazurov D, Herschhorn A. Ultrasensitive quantification of HIV-1 cell-to-cell transmission in primary human CD4 + T cells measures viral sensitivity to broadly neutralizing antibodies. mBio 2024; 15:e0242823. [PMID: 38063394 PMCID: PMC10790777 DOI: 10.1128/mbio.02428-23] [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: 09/06/2023] [Accepted: 11/07/2023] [Indexed: 01/17/2024] Open
Abstract
IMPORTANCE HIV-1 can efficiently transmit from one cell to another but accurate quantification of this mode of transmission is still challenging. Here, we developed an ultrasensitive assay to measure HIV-1 transmission between cells and to evaluate HIV-1 escape from broadly neutralizing antibodies in primary human T cells. This assay will contribute to understanding the fundamental mechanisms of HIV-1 cell-to-cell transmission, allow evaluation of pre-existing or acquired HIV-1 resistance in clinical trials, and can be adapted to study the biology of other retroviruses.
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Affiliation(s)
- Dmitriy Mazurov
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Alon Herschhorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, USA
- Institute for Engineering in Medicine, Center for Genome Engineering, University of Minnesota, Minneapolis, Minnesota, USA
- Microbiology, Immunology, and Cancer Biology Graduate Program, University of Minnesota, Minneapolis, Minnesota, USA
- The College of Veterinary Medicine Graduate Program, University of Minnesota, Minneapolis, Minnesota, USA
- Molecular Pharmacology and Therapeutics Graduate Program, University of Minnesota, Minneapolis, Minnesota, USA
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4
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Parthasarathy D, Pothula KR, Dam KMA, Ratnapriya S, Benet HC, Parsons R, Huang X, Sammour S, Janowska K, Harris M, Sacco S, Sodroski J, Bridges MD, Hubbell WL, Acharya P, Herschhorn A. Conformational flexibility of HIV-1 envelope glycoproteins modulates transmitted / founder sensitivity to broadly neutralizing antibodies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.13.557082. [PMID: 37745449 PMCID: PMC10515946 DOI: 10.1101/2023.09.13.557082] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
HIV-1 envelope glycoproteins (Envs) mediate viral entry and are the sole target of neutralizing antibodies. Envs of most primary HIV-1 strains exist in a closed conformation and occasionally sample more open states. Thus, current knowledge guides immunogen design to mimic the closed Env conformation as the preferred target for eliciting broadly neutralizing antibodies (bnAbs) to block HIV-1 entry. Here we show that Env-preferred conformations of 6 out of 13 (46%) transmitted/founder (T/F) strains tested are incompletely closed. As a result, entry of these T/Fs into target cells is sensitive to antibodies that recognize internal epitopes exposed on open Env conformations. A cryo-electron microscopy structure of unliganded, incompletely closed T/F Envs (1059-SOSIP) at 3.6 Å resolution exhibits an asymmetric configuration of Env protomers with increased sampling of states with incompletely closed trimer apex. Double electron-electron resonance spectroscopy provided further evidence for enriched occupancy of more open Env conformations. Consistent with conformational flexibility, 1059 Envs were associated with resistance to most bnAbs that exhibit reduced potency against functional Env intermediates. To follow the fate of incompletely closed Env in patients, we reconstructed de novo the post-transmission evolutionary pathway of a second T/F Env (CH040), which is sensitive to the V3-targeting antibody 19b and highly resistant to most bnAbs. Evolved viruses exhibited increased resistance to cold, soluble CD4 and 19b, all of which correlate with closing of the adapted Env trimer. Lastly, we show a correlation between efficient neutralization of multiple Env conformations and increased antiviral breadth of CD4-binding site (CD4bs) bnAbs. In particular, N6 bnAb, which uniquely recognizes different Env conformations, efficiently neutralizes 50% of the HIV-1 strains that were resistant to VRC01 and transmitted during the first-in-humans antibody-mediated prevention trial (HVTN 704). VRC01-resistant Envs are incompletely closed based on their sensitivity to cold and on partial sensitivity to antibodies targeting internal, typically occluded, epitopes. Most VRC01-resistant Envs retain the VRC01 epitope according to VRC01 binding to their gp120 subunit at concentrations that have no significant effect on virus entry, and they exhibit cross resistance to other CD4bs bnAbs that poorly recognize functional Env intermediates. Our findings refine current knowledge of Env conformational states and provide guidance for developing new strategies for bnAb immunotherapy and Env-based immunogen design.
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Affiliation(s)
- Durgadevi Parthasarathy
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
- These authors contributed equally: Durgadevi Parthasarathy and Karunakar Reddy Pothula
| | - Karunakar Reddy Pothula
- Duke Human Vaccine Institute, Durham, NC, USA
- These authors contributed equally: Durgadevi Parthasarathy and Karunakar Reddy Pothula
| | - Kim-Marie A. Dam
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Sneha Ratnapriya
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Héctor Cervera Benet
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | | | - Xiao Huang
- Duke Human Vaccine Institute, Durham, NC, USA
| | | | | | - Miranda Harris
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Samuel Sacco
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Present address: Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, USA; Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Michael D. Bridges
- Jules Stein Eye Institute, University of California, Los Angeles, CA, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Wayne L. Hubbell
- Jules Stein Eye Institute, University of California, Los Angeles, CA, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Priyamvada Acharya
- Duke Human Vaccine Institute, Durham, NC, USA
- Department of Surgery, and Department of Biochemistry, Duke University, Durham, NC, USA
| | - Alon Herschhorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA
- Microbiology, Immunology, and Cancer Biology Graduate Program; The College of Veterinary Medicine Graduate Program; and the Molecular Pharmacology and Therapeutics Graduate Program, University of Minnesota, Minneapolis, MN, USA
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5
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Ahmed S, Parthasarathy D, Newhall R, Picard T, Aback M, Ratnapriya S, Arndt W, Vega-Rodriguez W, Kirk NM, Liang Y, Herschhorn A. Enhancing anti-viral neutralization response to immunization with HIV-1 envelope glycoprotein immunogens. NPJ Vaccines 2023; 8:181. [PMID: 37996435 PMCID: PMC10667240 DOI: 10.1038/s41541-023-00774-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 11/06/2023] [Indexed: 11/25/2023] Open
Abstract
An effective human immunodeficiency virus type I (HIV-1) vaccine that robustly elicits broadly neutralizing antibodies (bnAbs) against HIV-1 envelope glycoproteins (Envs) to block viral entry is still not available. Thus, identifying triggers for elicitation of different types of anti-HIV-1 Env antibodies by vaccination could provide further guidance for immunogen design and vaccine development. Here, we studied the immune response to HIV-1 Env immunogens in rabbits. We show that sequential immunizations with conformation-specific Env immunogens can elicit low titer but broad neutralization responses against heterologous, neutralization-resistant (tier 2/3) transmitted/founder (T/F) HIV-1 strains. More importantly, an mRNA vaccine candidate that could mediate the presentation of a cytoplasmic tail-deleted (ΔCT) HIV-1AD8 Env immunogen on virus-like particles significantly increased the neutralization response. This strategy shifted the type of elicited antibodies, decreasing the level of binding to soluble Envs while significantly increasing their overall viral neutralization activity. The breadth and potency of neutralizing response against heterologous, T/F HIV-1 strains significantly increased in a subset of rabbits. Efficient neutralization activity was associated with high cellular immune responses specific to HIV-1 Envs. These results help to understand the immune response to different immunization schemes and will allow developing new approaches to selectively manipulate the type of humoral immune response by specific vaccination.
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Affiliation(s)
- Shamim Ahmed
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Durgadevi Parthasarathy
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Rachael Newhall
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Tashina Picard
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Morgainne Aback
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Sneha Ratnapriya
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, 55455, USA
| | - William Arndt
- School of Dentistry, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Widaliz Vega-Rodriguez
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St Paul, MN, 55108, USA
| | - Natalie M Kirk
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St Paul, MN, 55108, USA
| | - Yuying Liang
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St Paul, MN, 55108, USA
| | - Alon Herschhorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, 55455, USA.
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, 55455, USA.
- Microbiology, Immunology, and Cancer Biology Graduate Program, University of Minnesota, Minneapolis, MN, 55455, USA.
- The College of Veterinary Medicine Graduate Program, University of Minnesota, Minneapolis, MN, 55455, USA.
- Molecular Pharmacology and Therapeutics Graduate Program, University of Minnesota, Minneapolis, MN, 55455, USA.
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6
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Jeffy J, Parthasarathy D, Ahmed S, Cervera-Benet H, Xiong U, Harris M, Mazurov D, Pickthorn S, Herschhorn A. Alternative substitutions of N332 in HIV-1 AD8 gp120 differentially affect envelope glycoprotein function and viral sensitivity to broadly neutralizing antibodies targeting the V3-glycan. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.20.567910. [PMID: 38045336 PMCID: PMC10690231 DOI: 10.1101/2023.11.20.567910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
The envelope glycoprotein (Env) trimer on the surface of human immunodeficiency virus type I (HIV-1) mediates viral entry into host CD4+ T cells and is the sole target of neutralizing antibodies. Broadly neutralizing antibodies (bnAbs) that target gp120 V3-glycan of HIV-1 Env trimer are potent and block the entry of diverse HIV-1 strains. Most V3-glycan bnAbs interact, to a different extent, with a glycan attached to N332 but Asn at this position is not absolutely conserved or required for HIV-1 entry based on prevalence of N332 in different circulating HIV-1 strains from diverse clades. Here, we studied the effects of amino acid changes at position 332 of HIV-1AD8 Envs on HIV-1 sensitivity to antibodies, cold exposure, and soluble CD4. We further investigated how these changes affect Env function and HIV-1 infectivity in vitro. Our results suggest robust tolerability of HIV-1AD8 Env N332 to changes with specific changes that resulted in extended exposure of gp120 V3 loop, which is typically concealed in most primary HIV-1 isolates. Viral evolution leading to Asn at position 332 of HIVAD8 Envs is supported by the selection advantage of high levels of cell-cell fusion, transmission, and infectivity even though cell surface expression levels are lower than most N332 variants. Thus, tolerance of HIV-1AD8 Envs to different amino acids at position 332 provides increased flexibility to respond to changing conditions/environments and to evade the immune system. Modeling studies of the distance between N332 glycan and specific bnAbs was in agreement with N332 glycan dependency on bnAb neutralization. Overall, our studies provide insights into the contribution of specific amino acids at position 332 to Env antigenicity, stability on ice, and conformational states.
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Affiliation(s)
- Jeffy Jeffy
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Durgadevi Parthasarathy
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Shamim Ahmed
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Héctor Cervera-Benet
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Ulahn Xiong
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Miranda Harris
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Dmitriy Mazurov
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Stephanie Pickthorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Alon Herschhorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
- Institute of Engineering and Medicine, University of Minnesota, Minneapolis, MN 55455, USA
- Center of Genomic Engineering, University of Minnesota, Minneapolis, MN 55455, USA
- Microbiology, Immunology, and Cancer Biology Graduate Program, the College of Veterinary Medicine Graduate Program, and Molecular Pharmacology and Therapeutics Graduate Program, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Herschhorn A. Indirect Mechanisms of HIV-1 Evasion from Broadly Neutralizing Antibodies In Vivo. ACS Infect Dis 2023; 9:5-8. [PMID: 36512322 DOI: 10.1021/acsinfecdis.2c00573] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Alon Herschhorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Microbiology, Immunology, and Cancer Biology Graduate Program, University of Minnesota, Minneapolis, Minnesota 55455, United States.,The College of Veterinary Medicine Graduate Program, University of Minnesota, Minneapolis, Minnesota 55455, United States
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8
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Schapiro HM, Khasnis MD, Ahn K, Karagiaridi A, Hayden S, Cilento ME, Root MJ. Regulation of epitope exposure in the gp41 membrane-proximal external region through interactions at the apex of HIV-1 Env. PLoS Pathog 2022; 18:e1010531. [PMID: 35584191 PMCID: PMC9154124 DOI: 10.1371/journal.ppat.1010531] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 05/31/2022] [Accepted: 04/18/2022] [Indexed: 11/19/2022] Open
Abstract
Glycoprotein Env of human immunodeficiency virus type 1 (HIV-1) mediates viral entry through membrane fusion. Composed of gp120 and gp41 subunits arranged as a trimer-of-heterodimers, Env adopts a metastable, highly dynamic conformation on the virion surface. This structural plasticity limits the temporospatial exposure of many highly conserved, neutralizing epitopes, contributing to the difficulty in developing effective HIV-1 vaccines. Here, we employed antibody neutralization of HIV-1 infectivity to investigate how inter- and intra-gp120 interactions mediated by variable loops V1/V2 and V3 at the Env apex regulate accessibility of the gp41 membrane-proximal external region (MPER) at the Env base. Swapping the V3 loop from EnvSF162 into the EnvHXB2 background shifted MPER exposure from the prefusogenic state to a functional intermediate conformation that was distinct from the prehairpin-intermediate state sensitive to gp41-targeted fusion inhibitors. The V3-loop swap had a profound impact on global protein dynamics, biasing the equilibrium to a closed conformation resistant to most anti-gp120 antibodies, stabilizing the protein to both cold- and soluble CD4-induced Env inactivation, and increasing the CD4 requirements for viral entry. Further dissection of the EnvHXB2 V3 loop revealed that residue 306 uniquely modulated epitope exposure and trimer stability. The R306S substitution substantially decreased sensitivity to antibodies targeting the gp41 MPER and, surprisingly, the gp120 V3-loop crown (residues 312–315), but had only modest effects on exposure of intervening gp120 epitopes. Furthermore, the point mutation reduced soluble CD4-induced inactivation, but had no impact on cold inactivation. The residue appeared to exert its effects by electrostatically modifying the strength of intra-subunit interactions between the V1/V2 and V3 loops. The distinct patterns of neutralization and stability pointed to a novel prefusogenic Env conformation along the receptor activation pathway and suggested that apical Env-regulation of gp41 MPER exposure can be decoupled from much of the dynamics of gp120 subunits. Surface glycoprotein Env is the main target for neutralizing antibodies elicited by HIV-1 vaccines. Env spontaneously fluctuates among different structures, limiting exposure of many attractive antibody-binding epitopes and, thereby, confounding vaccine development. To characterize these fluctuations, we examined how exposure of the MPER epitope found at the base of Env is regulated by interactions of the V3 loop located in the apex. Starting with an extremely flexible Env with a readily-exposed MPER, we identified two alterations that substantially restricted antibody access to the epitope. The first, a wholesale swap of V3 loops between HIV-1 strains, energetically stabilized Env in a closed structure that restricted access to antibodies throughout the protein. The second, a point mutation that altered V3-loop charge, specifically destabilized the MPER-exposed conformation but had minimal impact on antibody access to Env regions in between the apex and base. The results indicate that MPER exposure is not explicitly tied to the dynamics of Env regions between the apex and base and suggest a new structural fluctuation during Env activation.
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Affiliation(s)
- Hannah M. Schapiro
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Mukta D. Khasnis
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Koree Ahn
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Alexandra Karagiaridi
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Stephanie Hayden
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Maria E. Cilento
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Michael J. Root
- Department of Microbial Infection and Immunity, The Ohio State University College of Medicine, Columbus, Ohio, United States of America
- * E-mail:
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9
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Carlon-Andres I, Malinauskas T, Padilla-Parra S. Structure dynamics of HIV-1 Env trimers on native virions engaged with living T cells. Commun Biol 2021; 4:1228. [PMID: 34707229 PMCID: PMC8551276 DOI: 10.1038/s42003-021-02658-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 09/09/2021] [Indexed: 11/29/2022] Open
Abstract
The HIV-1 envelope glycoprotein (Env) mediates viral entry into the host cell. Although the highly dynamic nature of Env intramolecular conformations has been shown with single molecule spectroscopy in vitro, the bona fide Env intra- and intermolecular mechanics when engaged with live T cells remains unknown. We used two photon fast fluorescence lifetime imaging detection of single-molecule Förster Resonance Energy Transfer occurring between fluorescent labels on HIV-1 Env on native virions. Our observations reveal Env dynamics at two levels: transitions between different intramolecular conformations and intermolecular interactions between Env within the viral membrane. Furthermore, we show that three broad neutralizing anti-Env antibodies directed to different epitopes restrict Env intramolecular dynamics and interactions between adjacent Env molecules when engaged with living T cells. Importantly, our results show that Env-Env interactions depend on efficient virus maturation, and that is disrupted upon binding of Env to CD4 or by neutralizing antibodies. Thus, this study illuminates how different intramolecular conformations and distribution of Env molecules mediate HIV-1 Env-T cell interactions in real time and therefore might control immune evasion.
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Affiliation(s)
- Irene Carlon-Andres
- Department of Infectious Diseases, King's College London, Faculty of Life Sciences & Medicine, London, United Kingdom.
- Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom.
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.
| | - Tomas Malinauskas
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Sergi Padilla-Parra
- Department of Infectious Diseases, King's College London, Faculty of Life Sciences & Medicine, London, United Kingdom.
- Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom.
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.
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Khrustalev VV. The PentaFOLD 3.0 Algorithm for the Selection of Stable Elements of Secondary Structure to be Included in Vaccine Peptides. Protein Pept Lett 2021; 28:573-588. [PMID: 33172366 DOI: 10.2174/0929866527666201110123851] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/18/2020] [Accepted: 10/19/2020] [Indexed: 12/18/2022]
Abstract
AIMS The aim of this study was to create a new version of the PentaFOLD algorithm and to test its performance experimentally in several proteins and peptides. BACKGROUND Synthetic vaccines can cause production of neutralizing antibodies only in case if short peptides form the same secondary structure as fragments of full-length proteins. The Penta- FOLD 3.0 algorithm was designed to check stability of alpha helices, beta strands, and random coils using several propensity scales obtained during analysis of 1730 3D structures of proteins. OBJECTIVE The algorithm has been tested in the three peptides known to keep the secondary structure of the corresponding fragments of full-length proteins: the NY25 peptide from the Influenza H1N1 hemagglutinin, the SF23 peptide from the diphtheria toxin, the NQ21 peptide from the HIV1 gp120; as well as in the CC36 peptide from the human major prion protein. METHODS Affine chromatography for antibodies against peptides accompanied by circular dichroism and fluorescence spectroscopy were used to check the predictions of the algorithm. RESULTS Immunological experiments showed that all abovementioned peptides are more or less immunogenic in rabbits. The fact that antibodies against the NY25, the SF23, and the NQ21 form stable complexes with corresponding full-length proteins has been confirmed by affine chromatography. The surface of SARS CoV-2 spike receptor-binding domain interacting with hACE2 has been shown to be unstable according to the results of the PentaFOLD 3.0. CONCLUSION The PentaFOLD 3.0 algorithm (http://chemres.bsmu.by/PentaFOLD30.htm) can be used with the aim to design vaccine peptides with stable secondary structure elements.
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Ang CG, Carter E, Haftl A, Zhang S, Rashad AA, Kutzler M, Abrams CF, Chaiken IM. Peptide Triazole Thiol Irreversibly Inactivates Metastable HIV-1 Env by Accessing Conformational Triggers Intrinsic to Virus-Cell Entry. Microorganisms 2021; 9:1286. [PMID: 34204725 PMCID: PMC8231586 DOI: 10.3390/microorganisms9061286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 06/03/2021] [Accepted: 06/09/2021] [Indexed: 11/16/2022] Open
Abstract
KR13, a peptide triazole thiol previously established to inhibit HIV-1 infection and cause virus lysis, was evaluated by flow cytometry against JRFL Env-presenting cells to characterize induced Env and membrane transformations leading to irreversible inactivation. Transiently transfected HEK293T cells were preloaded with calcein dye, treated with KR13 or its thiol-blocked analogue KR13b, fixed, and stained for gp120 (35O22), MPER (10E8), 6-helix-bundle (NC-1), immunodominant loop (50-69), and fusion peptide (VRC34.01). KR13 induced dose-dependent transformations of Env and membrane characterized by transient poration, MPER exposure, and 6-helix-bundle formation (analogous to native fusion events), but also reduced immunodominant loop and fusion peptide exposure. Using a fusion peptide mutant (V504E), we found that KR13 transformation does not require functional fusion peptide for poration. In contrast, simultaneous treatment with fusion inhibitor T20 alongside KR13 prevented membrane poration and MPER exposure, showing that these events require 6-helix-bundle formation. Based on these results, we formulated a model for PTT-induced Env transformation portraying how, in the absence of CD4/co-receptor signaling, PTT may provide alternate means of perturbing the metastable Env-membrane complex, and inducing fusion-like transformation. In turn, the results show that such transformations are intrinsic to Env and can be diverted for irreversible inactivation of the protein complex.
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Affiliation(s)
- Charles Gotuaco Ang
- Department of Biochemistry and Molecular Biology, College of Medicine, Drexel University, Philadelphia, PA 19102, USA; (E.C.); (A.H.); (S.Z.); (A.A.R.)
- School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA 19102, USA
| | - Erik Carter
- Department of Biochemistry and Molecular Biology, College of Medicine, Drexel University, Philadelphia, PA 19102, USA; (E.C.); (A.H.); (S.Z.); (A.A.R.)
- Departments of Medicine and Microbiology and Immunology, College of Medicine, Drexel University, Philadelphia, PA 19102, USA;
| | - Ann Haftl
- Department of Biochemistry and Molecular Biology, College of Medicine, Drexel University, Philadelphia, PA 19102, USA; (E.C.); (A.H.); (S.Z.); (A.A.R.)
- Department of Chemistry, College of Arts and Sciences, Drexel University, Philadelphia, PA 19102, USA
| | - Shiyu Zhang
- Department of Biochemistry and Molecular Biology, College of Medicine, Drexel University, Philadelphia, PA 19102, USA; (E.C.); (A.H.); (S.Z.); (A.A.R.)
- School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA 19102, USA
| | - Adel A. Rashad
- Department of Biochemistry and Molecular Biology, College of Medicine, Drexel University, Philadelphia, PA 19102, USA; (E.C.); (A.H.); (S.Z.); (A.A.R.)
| | - Michele Kutzler
- Departments of Medicine and Microbiology and Immunology, College of Medicine, Drexel University, Philadelphia, PA 19102, USA;
| | - Cameron F. Abrams
- Department of Chemical and Biological Engineering, College of Engineering, Drexel University, Philadelphia, PA 19102, USA;
| | - Irwin M. Chaiken
- Department of Biochemistry and Molecular Biology, College of Medicine, Drexel University, Philadelphia, PA 19102, USA; (E.C.); (A.H.); (S.Z.); (A.A.R.)
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Cervera H, Ratnapriya S, Chov A, Herschhorn A. Changes in the V1 Loop of HIV-1 Envelope Glycoproteins Can Allosterically Modulate the Trimer Association Domain and Reduce PGT145 Sensitivity. ACS Infect Dis 2021; 7:1558-1568. [PMID: 34006087 DOI: 10.1021/acsinfecdis.0c00899] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Human immunodeficiency virus (HIV-1) envelope glycoproteins (Envs) are a main focus of immunogen design and vaccine development. Broadly neutralizing antibodies (bnAbs) against HIV-1 Envs target conserved epitopes and neutralize multiple HIV-1 viral strains. Nevertheless, application of bnAbs to therapy and prevention is limited by resistant strains that are developed or preexist within the viral population. Here we studied the HIV-1NAB9 Envs that were isolated from a person who injects drugs and exhibits high and broad resistance to multiple bnAbs. We identified an insertion of 11 amino acids in the V1 loop that allosterically modulates HIV-1NAB9 sensitivity to the PGT145 bnAb, which targets the Env trimer association domain and supports high level viral infectivity. Our data provide new insights into the mechanisms of HIV-1 resistance to bnAbs and into allosteric connectivity between different HIV-1 Env domains.
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Affiliation(s)
- Héctor Cervera
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Sneha Ratnapriya
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Angela Chov
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Alon Herschhorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Microbiology, Immunology, and Cancer Biology Graduate Program, University of Minnesota, Minneapolis, Minnesota 55455, United States
- The College of Veterinary Medicine Graduate Program, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota 55455, United States
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13
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Slow Receptor Binding of the Noncytopathic HIV-2 UC1 Envs Is Balanced by Long-Lived Activation State and Efficient Fusion Activity. Cell Rep 2021; 31:107749. [PMID: 32521274 DOI: 10.1016/j.celrep.2020.107749] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 04/20/2020] [Accepted: 05/18/2020] [Indexed: 01/08/2023] Open
Abstract
Many HIV strains downregulate the levels of CD4 receptor on the surface of infected cells to prevent superinfection. In contrast, the rare HIV-2UC1 strain is noncytopathic and has no effect on CD4 expression in infected cells but still replicates as efficiently as more cytopathic strains in peripheral blood mononuclear cells (PBMCs). Here, we show that HIV-2UC1 Env interactions with the CD4 receptor exhibit slow association kinetics, whereas the dissociation kinetics is within the range of cytopathic strains. Despite the resulting 10- to 100-fold decrease in binding affinity, HIV-2UC1 Envs exhibit long-lived activation state and efficient fusion activity. These observations suggest that HIV-2UC1 Envs evolved to balance low affinity with an improved and readily triggerable molecular machinery to mediate entry. Resistance to cold exposure, similar to many primary HIV-1 isolates, and to sCD4 neutralization suggests that HIV-2UC1 Envs preferentially sample a closed Env conformation. Our data provide insights into the mechanism of HIV entry.
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Differential expression of HIV envelope epitopes on the surface of HIV-Infected macrophages and CD4 + T cells. Antiviral Res 2021; 191:105085. [PMID: 33961905 DOI: 10.1016/j.antiviral.2021.105085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/28/2021] [Accepted: 05/01/2021] [Indexed: 11/23/2022]
Abstract
HIV-infected macrophages contribute to persistence of HIV reservoirs in people living with HIV receiving antiretroviral therapy. A potential strategy to eliminate reservoirs is the use of antibody-dependent cellular cytotoxicity (ADCC) against infected cells expressing the HIV envelope (Env) protein on their surface. Designing ADCC strategies requires knowledge of exposed Env epitopes on the cell surface and identifying antibodies capable of opsonising infected cells, yet little is known regarding the ability of HIV-infected macrophages to be targeted with such strategies. Using a panel of neutralising and poorly-neutralising anti-Env antibodies we compared Env epitopes expressed on infected monocyte-derived macrophages (MDM) and autologous T cells. Our results reveal potential differences in epitope expression on macrophage- and T cell-expressed Env. Notably, HIVBaL-infected macrophages were more susceptible to opsonisation by NIH45-46 (median = 40.4%) compared to infected T cells (13.6%; p = 0.002), which were more susceptible to opsonisation by 17b and 447.52D (88.6% and 45.6% respectively) compared to MDM (30% and 6.7%, p = 0.002 and 0.004 respectively). Furthermore, neutralising antibodies 10E8 and PGT145 were relatively ineffective at opsonising Env expressed on the surface of infected T cells or macrophages, indicating that the context in which Env is presented on infected cells may differ to that of cell-free virions.
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Ratnapriya S, Perez-Greene E, Schifanella L, Herschhorn A. Adjuvant-mediated enhancement of the immune response to HIV vaccines. FEBS J 2021; 289:3317-3334. [PMID: 33705608 DOI: 10.1111/febs.15814] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/28/2021] [Accepted: 03/08/2021] [Indexed: 12/26/2022]
Abstract
Protection from human immunodeficiency virus (HIV) acquisition will likely require an effective vaccine that elicits antibodies against the HIV-1 envelope glycoproteins (Envs), which are the sole target of neutralizing antibodies and a main focus of vaccine development. Adjuvants have been widely used to augment the magnitude and longevity of the adaptive immune responses to immunizations with HIV-1 Envs and to guide the development of specific immune responses. Here, we review the adjuvants that have been used in combination with HIV-1 Envs in several preclinical and human clinical trials in recent years. We summarize the interactions between the HIV-1 Envs and adjuvants, and highlight the routes of vaccine administration for various formulations. We then discuss the use of combinations of different adjuvants, the potential effect of adjuvants on the elicitation of antibodies enriched in somatic hypermutation and containing long complementarity-determining region 3 of the antibody heavy chain, and the elicitation of non-neutralizing antibodies.
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Affiliation(s)
- Sneha Ratnapriya
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Eva Perez-Greene
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Luca Schifanella
- Department of Surgery, Division of Surgical Outcomes and Precision Medicine Research, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Alon Herschhorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA.,Microbiology, Immunology, and Cancer Biology Graduate Program, University of Minnesota, Minneapolis, MN, USA.,The College of Veterinary Medicine Graduate Program, University of Minnesota, Minneapolis, MN, USA.,Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA
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Farzani TA, Chov A, Herschhorn A. A protocol for displaying viral envelope glycoproteins on the surface of vesicular stomatitis viruses. STAR Protoc 2020; 1:100209. [PMID: 33377103 PMCID: PMC7757661 DOI: 10.1016/j.xpro.2020.100209] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
We describe the production of single-cycle (sc) and replication-competent recombinant vesicular stomatitis viruses (rcVSVs) displaying heterologous envelope glycoproteins (Envs) on their surface. We prepare scVSVs by transiently expressing HIV-1 Envs or SARS-CoV-2 spike followed by infection of the cells with scVSV particles, which do not carry the vsv-g gene. To prepare rcVSVs, we replace the vsv-g with a specific env-encoding gene, transfect cells with multiple plasmids for production of the genomic RNA and viral proteins, and rescue replication-competent viruses.
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Affiliation(s)
- Touraj Aligholipour Farzani
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | - Angela Chov
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | - Alon Herschhorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
- Microbiology, Immunology, and Cancer Biology Graduate Program, University of Minnesota, Minneapolis, MN 55455, USA
- The College of Veterinary Medicine Graduate Program, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
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Abstract
HIV-1 envelope glycoproteins (Envs) bind to CD4 receptor and CCR5/CXCR4 coreceptor and mediate viral entry (Feng et al., 1996; Herschhorn et al., 2016, 2017; Kwong et al., 1998). HIV-1 Envs are the sole target of neutralizing antibodies and a main focus of vaccine development (Flemming et al., 2018). Here, we provide a step-by-step protocol to measure Env sensitivity to ligands, cold, and small molecules, as well as to study viral infectivity and to dissect parameters affecting HIV-1 Env function. For complete details on the use and execution of this protocol, please refer to Harris et al. (2020).
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Affiliation(s)
- Sneha Ratnapriya
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | - Angela Chov
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | - Alon Herschhorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA.,Microbiology, Immunology, and Cancer Biology Graduate Program, University of Minnesota, Minneapolis, MN 55455, USA.,The College of Veterinary Medicine Graduate Program, University of Minnesota, Minneapolis, MN 55455, USA.,Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
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