1
|
Parthasarathy D, Pothula KR, Ratnapriya S, Cervera Benet H, Parsons R, Huang X, Sammour S, Janowska K, Harris M, Sodroski J, Acharya P, Herschhorn A. Conformational flexibility of HIV-1 envelope glycoproteins modulates transmitted/founder sensitivity to broadly neutralizing antibodies. Nat Commun 2024; 15:7334. [PMID: 39187497 PMCID: PMC11347675 DOI: 10.1038/s41467-024-51656-4] [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: 07/07/2024] [Accepted: 08/09/2024] [Indexed: 08/28/2024] Open
Abstract
HIV-1 envelope glycoproteins (Envs) of most primary HIV-1 strains exist in closed conformation and infrequently sample open states, limiting access to internal epitopes. Thus, immunogen design aims to mimic the closed Env conformation as preferred target for eliciting broadly neutralizing antibodies (bnAbs). Here we identify incompletely closed Env conformations of 6 out of 13 transmitted/founder (T/F) strains that are sensitive to antibodies that recognize internal epitopes typically exposed on open Envs. A 3.6 Å cryo-electron microscopy structure of unliganded, incompletely closed T/F Envs (1059-SOSIP) reveals protomer motion that increased sampling of states with incompletely closed trimer apex. We reconstruct de novo the post-transmission evolutionary pathway of a second T/F. Evolved viruses exhibit increased Env resistance to cold, soluble CD4 and 19b, all of which correlate with closing of the adapted Env trimer. Lastly, we show that the ultra-broad N6 bnAb efficiently recognizes different Env conformations and exhibits improved antiviral breadth against VRC01-resistant Envs isolated during the first-in-humans antibody-mediated-prevention trial.
Collapse
Affiliation(s)
- Durgadevi Parthasarathy
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, 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
| | - Ruth Parsons
- Duke Human Vaccine Institute, Duke University, Durham, NC, USA
- Department of Biochemistry, Duke University, Durham, NC, USA
| | - Xiao Huang
- Duke Human Vaccine Institute, Duke University, Durham, NC, USA
| | - Salam Sammour
- Duke Human Vaccine Institute, Duke University, Durham, NC, USA
| | | | - Miranda Harris
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, 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
| | - Priyamvada Acharya
- Duke Human Vaccine Institute, Duke University, Durham, NC, USA
- Department of Biochemistry, Duke University, Durham, NC, USA
- Department of Surgery, 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, 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.
- Molecular Pharmacology and Therapeutics Graduate Program, University of Minnesota, Minneapolis, MN, USA.
| |
Collapse
|
2
|
Webb NE, Sevareid CM, Sanchez C, Tobin NH, Aldrovandi GM. Natural Variation in HIV-1 Entry Kinetics Map to Specific Residues and Reveal an Interdependence Between Attachment and Fusion. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.25.600587. [PMID: 38979136 PMCID: PMC11230229 DOI: 10.1101/2024.06.25.600587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
HIV-1 entry kinetics reflect the fluid motion of the HIV envelope glycoprotein through at least three major structural configurations that drive virus-cell membrane fusion. The lifetime of each state is an important component of potency for inhibitors that target them. We used the time-of-addition inhibitor assay and a novel analytical strategy to define the kinetics of pre-hairpin exposure (using T20) and co-receptor engagement (via. maraviroc), through a characteristic delay metric, across a variety of naturally occurring HIV Env isolates. Among 257 distinct HIV-1 envelope isolates we found a remarkable breadth of T20 and maraviroc delays ranging from as early as 30 seconds to as late as 60 minutes. The most extreme delays were observed among transmission-linked clade C isolates. We identified four single-residue determinants of late T20 and maraviroc delays that are associated with either receptor engagement or gp41 function. Comparison of these delays with T20 sensitivity suggest co-receptor engagement and fusogenic activity in gp41 act cooperatively but sequentially to drive entry. Our findings support current models of entry where co-receptor engagement drives gp41 eclipse and have strong implications for the design of entry inhibitors and antibodies that target transient entry states. Author Summary The first step of HIV-1 infection is entry, where virus-cell membrane fusion is driven by the HIV-1 envelope glycoprotein through a series of conformational changes. Some of the most broadly active entry inhibitors work by binding conformations that exist only transiently during entry. The lifetimes of these states and the kinetics of entry are important elements of inhibitor activity for which little is known. We demonstrate a remarkable range of kinetics among 257 diverse HIV-1 isolates and find that this phenotype is highly flexible, with multiple single-residue determinants. Examination of the kinetics of two conformational landmarks shed light on novel kinetic features that offer new details about the role of co-receptor engagement and provide a framework to explain entry inhibitor synergy.
Collapse
|
3
|
Wang Q, Zhang S, Nguyen HT, Sodroski J. Inhibition of human immunodeficiency virus (HIV-1) infectivity by expression of poorly or broadly neutralizing antibodies against Env in virus-producing cells. J Virol 2024; 98:e0159423. [PMID: 38289101 PMCID: PMC10878270 DOI: 10.1128/jvi.01594-23] [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: 11/30/2023] [Accepted: 12/19/2023] [Indexed: 02/21/2024] Open
Abstract
The human immunodeficiency virus (HIV-1) envelope (Env) glycoprotein precursor (gp160) trimerizes, is modified by high-mannose glycans in the endoplasmic reticulum, and is transported via Golgi and non-Golgi secretory pathways to the infected cell surface. In the Golgi, gp160 is partially modified by complex carbohydrates and proteolytically cleaved to produce the mature functional Env trimer, which is preferentially incorporated into virions. Broadly neutralizing antibodies (bNAbs) generally recognize the cleaved Env trimer, whereas poorly neutralizing antibodies (pNAbs) bind the conformationally flexible gp160. We found that expression of bNAbs, pNAbs, or soluble/membrane forms of the receptor, CD4, in cells producing HIV-1 all decreased viral infectivity. Four patterns of co-expressed ligand:Env were observed: (i) ligands (CD4, soluble CD4-Ig, and some pNAbs) that specifically recognize the CD4-bound Env conformation resulted in uncleaved Envs lacking complex glycans that were not incorporated into virions; (ii) other pNAbs produced Envs with some complex carbohydrates and severe defects in cleavage, which were relieved by brefeldin A treatment; (iii) bNAbs that recognize gp160 as well as mature Envs resulted in Envs with some complex carbohydrates and moderate decreases in virion Env cleavage; and (iv) bNAbs that preferentially recognize mature Envs produced cleaved Envs with complex glycans in cells and on virions. The low infectivity observed upon co-expression of pNAbs or CD4 could be explained by disruption of Env trafficking, reducing the level of Env and/or increasing the fraction of uncleaved Env on virions. In addition to bNAb effects on virion Env cleavage, the secreted bNAbs neutralized the co-expressed viruses.IMPORTANCEThe Env trimers on the HIV-1 mediate virus entry into host cells. Env is synthesized in infected cells, modified by complex sugars, and cleaved to form a mature, functional Env, which is incorporated into virus particles. Env elicits antibodies in infected individuals, some of which can neutralize the virus. We found that antibodies co-expressed in the virus-producing cell can disrupt Env transit to the proper compartment for cleavage and sugar modification and, in some cases, block incorporation into viruses. These studies provide insights into the processes by which Env becomes functional in the virus-producing cell and may assist attempts to interfere with these events to inhibit HIV-1 infection.
Collapse
Affiliation(s)
- Qian Wang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Shijian Zhang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - 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
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Glögl M, Friedrich N, Cerutti G, Lemmin T, Kwon YD, Gorman J, Maliqi L, Mittl PRE, Hesselman MC, Schmidt D, Weber J, Foulkes C, Dingens AS, Bylund T, Olia AS, Verardi R, Reinberg T, Baumann NS, Rusert P, Dreier B, Shapiro L, Kwong PD, Plückthun A, Trkola A. Trapping the HIV-1 V3 loop in a helical conformation enables broad neutralization. Nat Struct Mol Biol 2023; 30:1323-1336. [PMID: 37605043 PMCID: PMC10497408 DOI: 10.1038/s41594-023-01062-z] [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: 09/23/2022] [Accepted: 07/11/2023] [Indexed: 08/23/2023]
Abstract
The third variable (V3) loop on the human immunodeficiency virus 1 (HIV-1) envelope glycoprotein trimer is indispensable for virus cell entry. Conformational masking of V3 within the trimer allows efficient neutralization via V3 only by rare, broadly neutralizing glycan-dependent antibodies targeting the closed prefusion trimer but not by abundant antibodies that access the V3 crown on open trimers after CD4 attachment. Here, we report on a distinct category of V3-specific inhibitors based on designed ankyrin repeat protein (DARPin) technology that reinstitute the CD4-bound state as a key neutralization target with up to >90% breadth. Broadly neutralizing DARPins (bnDs) bound V3 solely on open envelope and recognized a four-turn amphipathic α-helix in the carboxy-terminal half of V3 (amino acids 314-324), which we termed 'αV3C'. The bnD contact surface on αV3C was as conserved as the CD4 binding site. Molecular dynamics and escape mutation analyses underscored the functional relevance of αV3C, highlighting the potential of αV3C-based inhibitors and, more generally, of postattachment inhibition of HIV-1.
Collapse
Affiliation(s)
- Matthias Glögl
- Institute for Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Nikolas Friedrich
- Institute for Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Gabriele Cerutti
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Thomas Lemmin
- Institute for Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Young D Kwon
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Jason Gorman
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Liridona Maliqi
- Institute for Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Peer R E Mittl
- Department of Biochemistry, University of Zurich (UZH), Zurich, Switzerland
| | - Maria C Hesselman
- Institute for Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Daniel Schmidt
- Institute for Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Jacqueline Weber
- Institute for Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Caio Foulkes
- Institute for Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Adam S Dingens
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Tatsiana Bylund
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Adam S Olia
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Raffaello Verardi
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Thomas Reinberg
- Department of Biochemistry, University of Zurich (UZH), Zurich, Switzerland
| | - Nicolas S Baumann
- Institute for Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Peter Rusert
- Institute for Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Birgit Dreier
- Department of Biochemistry, University of Zurich (UZH), Zurich, Switzerland
| | - Lawrence Shapiro
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Andreas Plückthun
- Department of Biochemistry, University of Zurich (UZH), Zurich, Switzerland
| | - Alexandra Trkola
- Institute for Medical Virology, University of Zurich (UZH), Zurich, Switzerland.
| |
Collapse
|
7
|
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.
Collapse
|
8
|
Tumba NL, Owen GR, Killick MA, Papathanasopoulos MA. Immunization with HIV-1 trimeric SOSIP.664 BG505 or Founder Virus C (FVCEnv) covalently complexed to two-domain CD4S60C elicits cross-clade neutralizing antibodies in New Zealand white rabbits. Vaccine X 2022; 12:100222. [PMID: 36262212 PMCID: PMC9573916 DOI: 10.1016/j.jvacx.2022.100222] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 09/21/2022] [Accepted: 09/28/2022] [Indexed: 11/22/2022] Open
Abstract
Background: An ongoing challenge in HIV-1 vaccine research is finding a novel HIV-1 envelope glycoprotein (Env)-based immunogen that elicits broadly cross-neutralizing antibodies (bnAbs) without requiring complex sequential immunization regimens to drive the required antibody affinity maturation. Previous vaccination studies have shown monomeric Env and Env trimers which contain the GCN4 leucine zipper trimerization domain and are covalently bound to the first two domains of CD4 (2dCD4S60C) generate potent bnAbs in small animals. Since SOSIP.664 trimers are considered the most accurate, conformationally intact representation of HIV-1 Env generated to date, this study further evaluated the immunogenicity of SOSIP.664 HIV Env trimers (the well characterized BG505 and FVCEnv) covalently complexed to 2dCD4S60C. Methods: Recombinant BG505 SOSIP.664 and FVCEnv SOSIP.664 were expressed in mammalian cells, purified, covalently coupled to 2dCD4S60C and antigenically characterized for their interaction with HIV-1 bnAbs. The immunogenicity of BG505 SOSIP.664-2dCD4S60C and FVCEnv SOSIP.664-2dCD4S60C was investigated in New Zealand white rabbits and compared to unliganded FVCEnv and 2dCD4S60C. Rabbit sera were tested for the presence of neutralizing antibodies against a panel of 17 pseudoviruses. Results: Both BG505 SOSIP.664-2dCD4S60C and FVCEnv SOSIP.664-2dCD4S60C elicited a potent, HIV-specific response in rabbits with antibodies having considerable potency and breadth (70.5% and 76%, respectively) when tested against a global panel of 17 pseudoviruses mainly composed of harder-to-neutralize multiple clade tier-2 pseudoviruses. Conclusion: BG505 SOSIP.664-2dCD4S60C and FVCEnvSOSIP.664-2dCD4S60C are highly immunogenic and elicit potent, broadly neutralizing antibodies, the extent of which has never been reported previously for SOSIP.664 trimers. Adding to our previous results, the ability to consistently elicit these types of potent, cross-neutralizing antibody responses is dependent on novel epitopes exposed following the covalent binding of Env (independent of sequence and conformation) to 2dCD4S60C. These findings justify further investment into research exploring modified open, CD4-bound Env conformations as novel vaccine immunogens.
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
Zhang S, Wang K, Wang WL, Nguyen HT, Chen S, Lu M, Go EP, Ding H, Steinbock RT, Desaire H, Kappes JC, Sodroski J, Mao Y. Asymmetric Structures and Conformational Plasticity of the Uncleaved Full-Length Human Immunodeficiency Virus Envelope Glycoprotein Trimer. J Virol 2021; 95:e0052921. [PMID: 34549974 PMCID: PMC8610584 DOI: 10.1128/jvi.00529-21] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 09/06/2021] [Indexed: 11/20/2022] Open
Abstract
The functional human immunodeficiency virus (HIV-1) envelope glycoprotein (Env) trimer [(gp120/gp41)3] is produced by cleavage of a conformationally flexible gp160 precursor. gp160 cleavage or the binding of BMS-806, an entry inhibitor, stabilizes the pretriggered, "closed" (state 1) conformation recognized by rarely elicited broadly neutralizing antibodies. Poorly neutralizing antibodies (pNAbs) elicited at high titers during natural infection recognize more "open" Env conformations (states 2 and 3) induced by binding the receptor, CD4. We found that BMS-806 treatment and cross-linking decreased the exposure of pNAb epitopes on cell surface gp160; however, after detergent solubilization, cross-linked and BMS-806-treated gp160 sampled non-state-1 conformations that could be recognized by pNAbs. Cryo-electron microscopy of the purified BMS-806-bound gp160 revealed two hitherto unknown asymmetric trimer conformations, providing insights into the allosteric coupling between trimer opening and structural variation in the gp41 HR1N region. The individual protomer structures in the asymmetric gp160 trimers resemble those of other genetically modified or antibody-bound cleaved HIV-1 Env trimers, which have been suggested to assume state-2-like conformations. Asymmetry of the uncleaved Env potentially exposes surfaces of the trimer to pNAbs. To evaluate the effect of stabilizing a state-1-like conformation of the membrane Env precursor, we treated cells expressing wild-type HIV-1 Env with BMS-806. BMS-806 treatment decreased both gp160 cleavage and the addition of complex glycans, implying that gp160 conformational flexibility contributes to the efficiency of these processes. Selective pressure to maintain flexibility in the precursor of functional Env allows the uncleaved Env to sample asymmetric conformations that potentially skew host antibody responses toward pNAbs. IMPORTANCE The envelope glycoprotein (Env) trimers on the surface of human immunodeficiency virus (HIV-1) mediate the entry of the virus into host cells and serve as targets for neutralizing antibodies. The functional Env trimer is produced by cleavage of the gp160 precursor in the infected cell. We found that the HIV-1 Env precursor is highly plastic, allowing it to assume different asymmetric shapes. This conformational plasticity is potentially important for Env cleavage and proper modification by sugars. Having a flexible, asymmetric Env precursor that can misdirect host antibody responses without compromising virus infectivity would be an advantage for a persistent virus like HIV-1.
Collapse
Affiliation(s)
- Shijian Zhang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Kunyu Wang
- State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Center for Quantitative Biology, Peking University, Beijing, China
| | - Wei Li Wang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Center for Quantitative Biology, Peking University, Beijing, China
- Intel Parallel Computing Center for Structural Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - 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
| | - Shuobing Chen
- State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Center for Quantitative Biology, Peking University, Beijing, China
| | - Maolin Lu
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Eden P. Go
- Department of Chemistry, University of Kansas, Lawrence, Kansas, USA
| | - Haitao Ding
- Department of Medicine, University of Alabama at Birmingham, Alabama, USA
| | - Robert T. Steinbock
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Heather Desaire
- Department of Chemistry, University of Kansas, Lawrence, Kansas, USA
| | - John C. Kappes
- Department of Medicine, University of Alabama at Birmingham, Alabama, USA
- Birmingham Veterans Affairs Medical Center, Research Service, Birmingham, Alabama, USA
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Youdong Mao
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Center for Quantitative Biology, Peking University, Beijing, China
- Intel Parallel Computing Center for Structural Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| |
Collapse
|
11
|
Friedrich N, Stiegeler E, Glögl M, Lemmin T, Hansen S, Kadelka C, Wu Y, Ernst P, Maliqi L, Foulkes C, Morin M, Eroglu M, Liechti T, Ivan B, Reinberg T, Schaefer JV, Karakus U, Ursprung S, Mann A, Rusert P, Kouyos RD, Robinson JA, Günthard HF, Plückthun A, Trkola A. Distinct conformations of the HIV-1 V3 loop crown are targetable for broad neutralization. Nat Commun 2021; 12:6705. [PMID: 34795280 PMCID: PMC8602657 DOI: 10.1038/s41467-021-27075-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 11/03/2021] [Indexed: 12/14/2022] Open
Abstract
The V3 loop of the HIV-1 envelope (Env) protein elicits a vigorous, but largely non-neutralizing antibody response directed to the V3-crown, whereas rare broadly neutralizing antibodies (bnAbs) target the V3-base. Challenging this view, we present V3-crown directed broadly neutralizing Designed Ankyrin Repeat Proteins (bnDs) matching the breadth of V3-base bnAbs. While most bnAbs target prefusion Env, V3-crown bnDs bind open Env conformations triggered by CD4 engagement. BnDs achieve breadth by focusing on highly conserved residues that are accessible in two distinct V3 conformations, one of which resembles CCR5-bound V3. We further show that these V3-crown conformations can, in principle, be attacked by antibodies. Supporting this conclusion, analysis of antibody binding activity in the Swiss 4.5 K HIV-1 cohort (n = 4,281) revealed a co-evolution of V3-crown reactivities and neutralization breadth. Our results indicate a role of V3-crown responses and its conformational preferences in bnAb development to be considered in preventive and therapeutic approaches.
Collapse
Affiliation(s)
- Nikolas Friedrich
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Emanuel Stiegeler
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,grid.424277.0Present Address: Roche Diagnostics GmbH, Nonnenwald 2, 82377 Penzberg, Deutschland
| | - Matthias Glögl
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Thomas Lemmin
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,grid.5801.c0000 0001 2156 2780Department of Computer Science, ETH Zurich, Zurich, Switzerland ,grid.29078.340000 0001 2203 2861Present Address: Euler Institute, Faculty of Biomedicine, Università della Svizzera italiana (USI), Lugano, Switzerland
| | - Simon Hansen
- grid.7400.30000 0004 1937 0650Department of Biochemistry, University of Zurich (UZH), Zurich, Switzerland ,Present Address: NGM Bio, 333 Oysterpoint Blvd, South San Francisco, CA 94080 USA
| | - Claus Kadelka
- grid.34421.300000 0004 1936 7312Department of Mathematics, Iowa State University, Ames, IA USA
| | - Yufan Wu
- grid.7400.30000 0004 1937 0650Department of Biochemistry, University of Zurich (UZH), Zurich, Switzerland ,Present Address: Innovent Biologics Inc, 168 Dongping Street, Suzhou Industrial Park, 215123 China
| | - Patrick Ernst
- grid.7400.30000 0004 1937 0650Department of Biochemistry, University of Zurich (UZH), Zurich, Switzerland ,grid.7400.30000 0004 1937 0650Present Address: Office Research and Teaching, Medical Faculty, University of Zurich, Zurich, Switzerland
| | - Liridona Maliqi
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Caio Foulkes
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Mylène Morin
- grid.7400.30000 0004 1937 0650Department of Chemistry, University of Zurich (UZH), Zurich, Switzerland ,Present Address: BeiGene Switzerland GmbH, Aeschengraben 27, 4051 Basel, Switzerland
| | - Mustafa Eroglu
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,Present Address: Janssen Vaccines AG, Rehhagstrasse 79, 3018 Bern, Switzerland
| | - Thomas Liechti
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,grid.419681.30000 0001 2164 9667Present Address: ImmunoTechnology Section, Vaccine Research Center, NIAID, NIH, Bethesda, MD USA
| | - Branislav Ivan
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,grid.410567.1Present Address: Laboratory Medicine, Division of Clinical Chemistry, University Hospital Basel, Basel, Switzerland
| | - Thomas Reinberg
- grid.7400.30000 0004 1937 0650Department of Biochemistry, University of Zurich (UZH), Zurich, Switzerland
| | - Jonas V. Schaefer
- grid.7400.30000 0004 1937 0650Department of Biochemistry, University of Zurich (UZH), Zurich, Switzerland ,grid.419481.10000 0001 1515 9979Present Address: Novartis Institutes for BioMedical Research, Chemical Biology & Therapeutics (CBT), Novartis Pharma AG, Virchow 16, 4056 Basel, Switzerland
| | - Umut Karakus
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Stephan Ursprung
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,grid.5335.00000000121885934Present Address: University of Cambridge School of Clinical Medicine, Department of Radiology, Cambridge, CB2 0QQ UK
| | - Axel Mann
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,Present Address: Roche Innovation Center Zurich, Roche Pharmaceutical Research and Early Development (pRED), Wagistrasse 10, 8952 Schlieren, Switzerland
| | - Peter Rusert
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland
| | - Roger D. Kouyos
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,grid.412004.30000 0004 0478 9977Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich (USZ), Zurich, Switzerland
| | - John A. Robinson
- grid.7400.30000 0004 1937 0650Department of Chemistry, University of Zurich (UZH), Zurich, Switzerland
| | - Huldrych F. Günthard
- grid.7400.30000 0004 1937 0650Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland ,grid.412004.30000 0004 0478 9977Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich (USZ), Zurich, Switzerland
| | - Andreas Plückthun
- grid.7400.30000 0004 1937 0650Department of Biochemistry, University of Zurich (UZH), Zurich, Switzerland
| | - Alexandra Trkola
- Institute of Medical Virology, University of Zurich (UZH), Zurich, Switzerland.
| |
Collapse
|
12
|
Griffith SA, McCoy LE. To bnAb or Not to bnAb: Defining Broadly Neutralising Antibodies Against HIV-1. Front Immunol 2021; 12:708227. [PMID: 34737737 PMCID: PMC8560739 DOI: 10.3389/fimmu.2021.708227] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 09/30/2021] [Indexed: 12/13/2022] Open
Abstract
Since their discovery, antibodies capable of broad neutralisation have been at the forefront of HIV-1 research and are of particular interest due to in vivo passive transfer studies demonstrating their potential to provide protection. Currently an exact definition of what is required for a monoclonal antibody to be classed as a broadly neutralising antibody (bnAb) has not yet been established. This has led to hundreds of antibodies with varying neutralisation breadth being studied and has given insight into antibody maturation pathways and epitopes targeted. However, even with this knowledge, immunisation studies and vaccination trials to date have had limited success in eliciting antibodies with neutralisation breadth. For this reason there is a growing need to identify factors specifically associated with bnAb development, yet to do this a set of criteria is necessary to distinguish bnAbs from non-bnAbs. This review aims to define what it means to be a HIV-1 bnAb by comparing neutralisation breadth, genetic features and epitopes of bnAbs, and in the process highlights the challenges of comparing the array of antibodies that have been isolated over the years.
Collapse
Affiliation(s)
- Sarah A Griffith
- Division of Infection and Immunity, Institute of Immunity and Transplantation, University College London, London, United Kingdom
| | - Laura E McCoy
- Division of Infection and Immunity, Institute of Immunity and Transplantation, University College London, London, United Kingdom
| |
Collapse
|
13
|
Zhang S, Holmes AP, Dick A, Rashad AA, Enríquez Rodríguez L, Canziani GA, Root MJ, Chaiken IM. Altered Env conformational dynamics as a mechanism of resistance to peptide-triazole HIV-1 inactivators. Retrovirology 2021; 18:31. [PMID: 34627310 PMCID: PMC8501640 DOI: 10.1186/s12977-021-00575-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 09/20/2021] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND We previously developed drug-like peptide triazoles (PTs) that target HIV-1 Envelope (Env) gp120, potently inhibit viral entry, and irreversibly inactivate virions. Here, we investigated potential mechanisms of viral escape from this promising class of HIV-1 entry inhibitors. RESULTS HIV-1 resistance to cyclic (AAR029b) and linear (KR13) PTs was obtained by dose escalation in viral passaging experiments. High-level resistance for both inhibitors developed slowly (relative to escape from gp41-targeted C-peptide inhibitor C37) by acquiring mutations in gp120 both within (Val255) and distant to (Ser143) the putative PT binding site. The similarity in the resistance profiles for AAR029b and KR13 suggests that the shared IXW pharmacophore provided the primary pressure for HIV-1 escape. In single-round infectivity studies employing recombinant virus, V255I/S143N double escape mutants reduced PT antiviral potency by 150- to 3900-fold. Curiously, the combined mutations had a much smaller impact on PT binding affinity for monomeric gp120 (four to ninefold). This binding disruption was entirely due to the V255I mutation, which generated few steric clashes with PT in molecular docking. However, this minor effect on PT affinity belied large, offsetting changes to association enthalpy and entropy. The escape mutations had negligible effect on CD4 binding and utilization during entry, but significantly altered both binding thermodynamics and inhibitory potency of the conformationally-specific, anti-CD4i antibody 17b. Moreover, the escape mutations substantially decreased gp120 shedding induced by either soluble CD4 or AAR029b. CONCLUSIONS Together, the data suggest that the escape mutations significantly modified the energetic landscape of Env's prefusogenic state, altering conformational dynamics to hinder PT-induced irreversible inactivation of Env. This work therein reveals a unique mode of virus escape for HIV-1, namely, resistance by altering the intrinsic conformational dynamics of the Env trimer.
Collapse
Affiliation(s)
- Shiyu Zhang
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA, USA
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, USA
| | - Andrew P Holmes
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA, USA
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Alexej Dick
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Adel A Rashad
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA, USA
| | | | - Gabriela A Canziani
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Michael J Root
- Department of Microbial Infection and Immunity, The Ohio State University College of Medicine, OH, Columbus, USA.
| | - Irwin M Chaiken
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA, USA.
| |
Collapse
|
14
|
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.
Collapse
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.)
| |
Collapse
|
15
|
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: 22] [Impact Index Per Article: 7.3] [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.
Collapse
|
16
|
Pye VE, Rosa A, Bertelli C, Struwe WB, Maslen SL, Corey R, Liko I, Hassall M, Mattiuzzo G, Ballandras-Colas A, Nans A, Takeuchi Y, Stansfeld PJ, Skehel JM, Robinson CV, Pizzato M, Cherepanov P. A bipartite structural organization defines the SERINC family of HIV-1 restriction factors. Nat Struct Mol Biol 2020; 27:78-83. [PMID: 31907454 PMCID: PMC6956856 DOI: 10.1038/s41594-019-0357-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 11/26/2019] [Indexed: 12/14/2022]
Abstract
The human integral membrane protein SERINC5 potently restricts HIV-1 infectivity and sensitizes the virus to antibody-mediated neutralization. Here, using cryo-EM, we determine the structures of human SERINC5 and its orthologue from Drosophila melanogaster at subnanometer and near-atomic resolution, respectively. The structures reveal a novel fold comprised of ten transmembrane helices organized into two subdomains and bisected by a long diagonal helix. A lipid binding groove and clusters of conserved residues highlight potential functional sites. A structure-based mutagenesis scan identified surface-exposed regions and the interface between the subdomains of SERINC5 as critical for HIV-1-restriction activity. The same regions are also important for viral sensitization to neutralizing antibodies, directly linking the antiviral activity of SERINC5 with remodeling of the HIV-1 envelope glycoprotein.
Collapse
Affiliation(s)
- Valerie E Pye
- Chromatin Structure and Mobile DNA Laboratory, Francis Crick Institute, London, UK
| | - Annachiara Rosa
- Chromatin Structure and Mobile DNA Laboratory, Francis Crick Institute, London, UK
| | - Cinzia Bertelli
- Department of Cellular, Computational and Integrative Biology, University of Trento, Povo, Italy
| | - Weston B Struwe
- Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, UK
| | - Sarah L Maslen
- Biological Mass Spectrometry and Proteomics Laboratory, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Robin Corey
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Idlir Liko
- Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, UK
| | - Mark Hassall
- National Institute for Biological Standards and Control, Hertfordshire, UK
| | - Giada Mattiuzzo
- National Institute for Biological Standards and Control, Hertfordshire, UK
| | | | - Andrea Nans
- Structural Biology Science Technology Platform, Francis Crick Institute, London, UK
| | - Yasuhiro Takeuchi
- National Institute for Biological Standards and Control, Hertfordshire, UK
- UCL Division of Infection and Immunity, The Rayne Building, London, UK
| | - Phillip J Stansfeld
- Department of Biochemistry, University of Oxford, Oxford, UK
- School of Life Sciences & Department of Chemistry, University of Warwick, Warwick, UK
| | - J Mark Skehel
- Biological Mass Spectrometry and Proteomics Laboratory, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Carol V Robinson
- Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, UK
| | - Massimo Pizzato
- Department of Cellular, Computational and Integrative Biology, University of Trento, Povo, Italy.
| | - Peter Cherepanov
- Chromatin Structure and Mobile DNA Laboratory, Francis Crick Institute, London, UK.
- Department of Infectious Disease, Imperial College London, St Mary's Campus, Norfolk Place, London, UK.
| |
Collapse
|
17
|
Chen B. Molecular Mechanism of HIV-1 Entry. Trends Microbiol 2019; 27:878-891. [PMID: 31262533 DOI: 10.1016/j.tim.2019.06.002] [Citation(s) in RCA: 161] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 05/20/2019] [Accepted: 06/05/2019] [Indexed: 11/19/2022]
Abstract
HIV-1 envelope glycoprotein [Env; trimeric (gp160)3 cleaved to (gp120/gp41)3] attaches the virion to a susceptible cell and induces fusion of viral and cell membranes to initiate infection. It interacts with the primary receptor CD4 and coreceptor (e.g., chemokine receptor CCR5 or CXCR4) to allow viral entry by triggering large structural rearrangements and unleashing the fusogenic potential of gp41 to induce membrane fusion. Recent advances in structural biology of HIV-1 Env and its complexes with the cellular receptors have revealed molecular details of HIV-1 entry and yielded new mechanistic insights. In this review, I summarize our latest understanding of the HIV-1 membrane fusion process and discuss possible pathways for productive viral entry.
Collapse
Affiliation(s)
- Bing Chen
- Division of Molecular Medicine, Boston Children's Hospital, and Department of Pediatrics, Harvard Medical School, 3 Blackfan Street, Boston, MA 02115, USA.
| |
Collapse
|
18
|
Broadly resistant HIV-1 against CD4-binding site neutralizing antibodies. PLoS Pathog 2019; 15:e1007819. [PMID: 31194843 PMCID: PMC6592578 DOI: 10.1371/journal.ppat.1007819] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 06/25/2019] [Accepted: 05/07/2019] [Indexed: 01/15/2023] Open
Abstract
Recently identified broadly neutralizing antibodies (bnAbs) show great potential for clinical interventions against HIV-1 infection. However, resistant strains may impose substantial challenges. Here, we report on the identification and characterization of a panel of HIV-1 strains with broad and potent resistance against a large number of bnAbs, particularly those targeting the CD4-binding site (CD4bs). Site-directed mutagenesis revealed that several key epitope mutations facilitate resistance and are located in the inner domain, loop D, and β23/loop V5/β24 of HIV-1 gp120. The resistance is largely correlated with binding affinity of antibodies to the envelope trimers expressed on the cell surface. Our results therefore demonstrate the existence of broadly resistant HIV-1 strains against CD4bs neutralizing antibodies. Treatment strategies based on the CD4bs bnAbs must overcome such resistance to achieve optimal clinical outcomes. Recently identified broadly neutralizing antibodies (bnAbs) show great potential for clinical interventions against HIV-1 infection. Among the bnAbs isolated to date, those targeting the CD4bs are the most abundant and thoroughly studied as they disrupt the crucial step of viral interaction with the cellular receptor molecule CD4. Despite the superior potency and breadth of these CD4bs bnAbs, each fails to neutralize a small but significant portion of pseudotyped virus panels. Here, we report on the identification and characterization of a panel of HIV-1 strains with broad and potent resistance against a large number of bnAbs, particularly those targeting the CD4bs. Resistance is largely attributed to mutated residues within the epitopes or steric hindrance imposed by the bulky side-chain or glycan shield of the mutated residues, and is largely correlated with reduced binding avidity of the antibody to the quaternary trimeric envelope protein expressed on the surface of the transfected cells. Treatment strategies based on the CD4bs bnAbs therefore must overcome such resistance to achieve optimal clinical outcomes.
Collapse
|
19
|
Anand SP, Grover JR, Tolbert WD, Prévost J, Richard J, Ding S, Baril S, Medjahed H, Evans DT, Pazgier M, Mothes W, Finzi A. Antibody-Induced Internalization of HIV-1 Env Proteins Limits Surface Expression of the Closed Conformation of Env. J Virol 2019; 93:e00293-19. [PMID: 30894474 PMCID: PMC6532100 DOI: 10.1128/jvi.00293-19] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 03/16/2019] [Indexed: 01/10/2023] Open
Abstract
To minimize immune responses against infected cells, HIV-1 limits the surface expression of its envelope glycoprotein (Env). Here, we demonstrate that this mechanism is specific for the Env conformation and affects the efficiency of antibody-dependent cellular cytotoxicity (ADCC). Using flow cytometry and confocal microscopy, we show that broadly neutralizing antibodies (bNAbs) targeting the "closed" conformation of Env induce its internalization from the surface. In contrast, non-neutralizing antibodies (nNAbs) are displayed on the cell surface for prolonged period of times. The bNAb-induced Env internalization can be decreased by blocking dynamin function, which translates into higher susceptibilities of infected cells to ADCC. Our results suggest that antibody-mediated Env internalization is a mechanism used by HIV-1 to evade immune responses against the "closed" conformation of Env expressed on HIV-1-infected cells.IMPORTANCE HIV-1 has evolved to acquire several strategies to limit the exposure of its envelope glycoproteins (Env) on the surface of infected cells. In this study, we show that antibody-induced Env internalization is conformation specific and reduces the susceptibility of infected cells to antibody-dependent cellular cytotoxicity (ADCC). Thus, a better understanding of this mechanism might help develop antibodies with improved capacities to mediate ADCC.
Collapse
Affiliation(s)
- Sai Priya Anand
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Jonathan R Grover
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - William D Tolbert
- Infectious Diseases Division, Department of Medicine of Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | | | - Shilei Ding
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Sophie Baril
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
| | | | - David T Evans
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, USA
- Wisconsin National Primate Research Center, University of Wisconsin, Madison, Wisconsin, USA
| | - Marzena Pazgier
- Infectious Diseases Division, Department of Medicine of Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| |
Collapse
|