1
|
Singh V, Bhutkar M, Choudhary S, Nehul S, Kumar R, Singla J, Kumar P, Tomar S. Structure-guided mutations in CDRs for enhancing the affinity of neutralizing SARS-CoV-2 nanobody. Biochem Biophys Res Commun 2024; 734:150746. [PMID: 39366179 DOI: 10.1016/j.bbrc.2024.150746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2024] [Revised: 09/05/2024] [Accepted: 09/24/2024] [Indexed: 10/06/2024]
Abstract
The optimization of antibodies to attain the desired levels of affinity and specificity holds great promise for the development of next generation therapeutics. This study delves into the refinement and engineering of complementarity-determining regions (CDRs) through in silico affinity maturation followed by binding validation using isothermal titration calorimetry (ITC) and pseudovirus-based neutralization assays. Specifically, it focuses on engineering CDRs targeting the epitopes of receptor-binding domain (RBD) of the spike protein of SARS-CoV-2. A structure-guided virtual library of 112 single mutations in CDRs was generated and screened against RBD to select the potential affinity-enhancing mutations. Protein-protein docking analysis identified 32 single mutants of which nine mutants were selected for molecular dynamics (MD) simulations. Subsequently, biophysical ITC studies provided insights into binding affinity, and consistent with in silico findings, six mutations that demonstrated better binding affinity than native nanobody were further tested in vitro for neutralization activity against SARS-CoV-2 pseudovirus. Leu106Thr mutant was found to be most effective in virus-neutralization with IC50 values of ∼0.03 μM, as compared to the native nanobody (IC50 ∼0.77 μM). Thus, in this study, the developed computational pipeline guided by structure-aided interface profiles and thermodynamic analysis holds promise for the streamlined development of antibody-based therapeutic interventions against emerging variants of SARS-CoV-2 and other infectious pathogens.
Collapse
Affiliation(s)
- Vishakha Singh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Uttarakhand, India
| | - Mandar Bhutkar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Uttarakhand, India
| | - Shweta Choudhary
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Uttarakhand, India
| | - Sanketkumar Nehul
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Uttarakhand, India
| | - Rajesh Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Uttarakhand, India
| | - Jitin Singla
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Uttarakhand, India; Department of Computer Science and Engineering, Indian Institute of Technology Roorkee, Uttarakhand, India
| | - Pravindra Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Uttarakhand, India
| | - Shailly Tomar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Uttarakhand, India.
| |
Collapse
|
2
|
Lee M, Changela A, Gorman J, Rawi R, Bylund T, Chao CW, Lin BC, Louder MK, Olia AS, Zhang B, Doria-Rose NA, Zolla-Pazner S, Shapiro L, Chuang GY, Kwong PD. Extended antibody-framework-to-antigen distance observed exclusively with broad HIV-1-neutralizing antibodies recognizing glycan-dense surfaces. Nat Commun 2021; 12:6470. [PMID: 34753907 PMCID: PMC8578620 DOI: 10.1038/s41467-021-26579-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 09/29/2021] [Indexed: 11/09/2022] Open
Abstract
Antibody-Framework-to-Antigen Distance (AFAD) - the distance between the body of an antibody and a protein antigen - is an important parameter governing antibody recognition. Here, we quantify AFAD for ~2,000 non-redundant antibody-protein-antigen complexes in the Protein Data Bank. AFADs showed a gaussian distribution with mean of 16.3 Å and standard deviation (σ) of 2.4 Å. Notably, antibody-antigen complexes with extended AFADs (>3σ) were exclusively human immunodeficiency virus-type 1 (HIV-1)-neutralizing antibodies. High correlation (R2 = 0.8110) was observed between AFADs and glycan coverage, as assessed by molecular dynamics simulations of the HIV-1-envelope trimer. Especially long AFADs were observed for antibodies targeting the glycosylated trimer apex, and we tested the impact of introducing an apex-glycan hole (N160K); the cryo-EM structure of the glycan hole-targeting HIV-1-neutralizing antibody 2909 in complex with an N160K-envelope trimer revealed a substantially shorter AFAD. Overall, extended AFADs exclusively recognized densely glycosylated surfaces, with the introduction of a glycan hole enabling closer recognition.
Collapse
Affiliation(s)
- Myungjin Lee
- Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Anita Changela
- Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jason Gorman
- Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Reda Rawi
- Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Tatsiana Bylund
- Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Cara W Chao
- Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Bob C Lin
- Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Mark K Louder
- Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Adam S Olia
- Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Baoshan Zhang
- Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Nicole A Doria-Rose
- Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Susan Zolla-Pazner
- Department of Medicine and Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Lawrence Shapiro
- Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, MD, 20892, USA.,Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, USA
| | - Gwo-Yu Chuang
- Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Peter D Kwong
- Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, MD, 20892, USA. .,Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, USA.
| |
Collapse
|
3
|
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
|
4
|
Zeneyedpour L, Sten-van `t Hoff J, Luider T. Using phosphoproteomics and next generation sequencing to discover novel therapeutic targets in patient antibodies. Expert Rev Proteomics 2020; 17:675-684. [DOI: 10.1080/14789450.2020.1845147] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Lona Zeneyedpour
- Department of Neurology, Erasmus MC, Laboratory of Neuro-Oncology/Clinical & Cancer Proteomics, Rotterdam, The Netherlands
| | - Jenny Sten-van `t Hoff
- Department of Neurology, Erasmus MC, Laboratory of Neuro-Oncology/Clinical & Cancer Proteomics, Rotterdam, The Netherlands
| | - Theo Luider
- Department of Neurology, Erasmus MC, Laboratory of Neuro-Oncology/Clinical & Cancer Proteomics, Rotterdam, The Netherlands
| |
Collapse
|
5
|
|
6
|
Zhou JO, Ton T, Morriss JW, Nguyen D, Fera D. Structural Insights from HIV-Antibody Coevolution and Related Immunization Studies. AIDS Res Hum Retroviruses 2018; 34:760-768. [PMID: 29984587 DOI: 10.1089/aid.2018.0097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) is a rapidly evolving pathogen that causes acquired immunodeficiency syndrome (AIDS) in humans. There are ∼30-35 million people infected with HIV around the world, and ∼25 million have died since the first reported cases in 1981. In addition, each year 2-3 million people become newly infected, and >1 million die of AIDS. An HIV-1 vaccine would help halt an AIDS pandemic, and efforts to develop a vaccine have focused on targeting the HIV-1 envelope, Env, found on the surface of the virus. A number of chronically infected individuals have been shown to produce antibodies, called broadly neutralizing antibodies (bnAbs), that target many strains of HIV-1 by binding to Env, thus suggesting promise for HIV-1 vaccine development. BnAbs take years to develop, and have a number of traits that inhibit their production; thus, a number of researchers are trying to understand the pathways that result in bnAb production, so that they can be elicited more rapidly by vaccination. This review discusses results and implications from two HIV-1-infected individuals studied longitudinally who produced bnAbs against two different sites on HIV-1 Env, and immunization studies that used Envs derived from those individuals.
Collapse
Affiliation(s)
- Jeffrey O. Zhou
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, Pennsylvania
| | - Therese Ton
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania
| | - Julia W. Morriss
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, Pennsylvania
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania
| | - Diep Nguyen
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, Pennsylvania
| | - Daniela Fera
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, Pennsylvania
| |
Collapse
|
7
|
Abstract
In 2009, Dimitrov's group reported that the inferred germline (iGL) forms of several HIV-1 broadly neutralizing antibodies (bNAbs) did not display measurable binding to a recombinant gp140 Env protein (derived from the dual-tropic 89.6 virus), which was efficiently recognized by the mature (somatically mutated) antibodies. At that time, a small number of bNAbs were available, but in the following years, the implementation of high-throughput B-cell isolation and sequencing assays and of screening methodologies facilitated the isolation of greater numbers of bNAbs from infected subjects. Using these newest bNAbs, and a wide range of diverse recombinant Envs, we and others confirmed the observations made by Dimitrov's group. The results from these studies created a paradigm shift in our collective thinking as to why recombinant Envs are ineffective in eliciting bNAbs and has led to the "germline-targeting" immunization approach. Here we discuss this approach in detail: what has been done so far, the advantages and limitations of the current germline-targeting immunogens and of the animal models used to test them, and we conclude with a few thoughts about future directions in this area of research.
Collapse
Affiliation(s)
- Leonidas Stamatatos
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.,Department of Global Health, University of Washington, Seattle, WA, USA
| | - Marie Pancera
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Andrew T McGuire
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| |
Collapse
|
8
|
Abstract
A brief outline of antibody structure is followed by highlights from several recently determined crystal structures of human, antiviral Fabs. These Fabs all have novel structural features that allow them to potently and broadly neutralize their targets.
Collapse
|
9
|
Immunogens Modeling a Fusion-Intermediate Conformation of gp41 Elicit Antibodies to the Membrane Proximal External Region of the HIV Envelope Glycoprotein. PLoS One 2015; 10:e0128562. [PMID: 26087072 PMCID: PMC4472232 DOI: 10.1371/journal.pone.0128562] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 04/28/2015] [Indexed: 12/02/2022] Open
Abstract
The membrane proximal external region (MPER) of the gp41 subunit of the HIV-1 envelope glycoprotein (Env) contains determinants for broadly neutralizing antibodies and has remained an important focus of vaccine design. However, creating an immunogen that elicits broadly neutralizing antibodies to this region has proven difficult in part due to the relative inaccessibility of the MPER in the native conformation of Env. Here, we describe the antigenicity and immunogenicity of a panel of oligomeric gp41 immunogens designed to model a fusion-intermediate conformation of Env in order to enhance MPER exposure in a relevant conformation. The immunogens contain segments of the gp41 N- and C-heptad repeats to mimic a trapped intermediate, followed by the MPER, with variations that include different N-heptad lengths, insertion of extra epitopes, and varying C-termini. These well-characterized immunogens were evaluated in two different immunization protocols involving gp41 and gp140 proteins, gp41 and gp160 DNA primes, and different immunization schedules and adjuvants. We found that the immunogens designed to reduce extension of helical structure into the MPER elicited the highest MPER antibody binding titers, but these antibodies lacked neutralizing activity. The gp41 protein immunogens also elicited higher MPER titers than the gp140 protein immunogen. In prime-boost studies, the best MPER responses were seen in the groups that received DNA priming with gp41 vectors followed by gp41 protein boosts. Finally, although titers to the entire protein immunogen were similar in the two immunization protocols, MPER-specific titers differed, suggesting that the immunization route, schedule, dose, or adjuvant may differentially influence MPER immunogenicity. These findings inform the design of future MPER immunogens and immunization protocols.
Collapse
|
10
|
Rahimi R, Ebtekar M, Moazzeni SM, Mostafaie A, Mahdavi M. Optimization of multi-epitopic HIV-1 recombinant protein expression in prokaryote system and conjugation to mouse DEC-205 monoclonal antibody: implication for in-vivo targeted delivery of dendritic cells. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2015; 18:145-52. [PMID: 25810888 PMCID: PMC4366725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVES Multi-epitopic protein vaccines and direction of vaccine delivery to dendritic cells (DCs) are promising approaches for enhancing immune responses against mutable pathogens. Escherichia coli is current host for expression of recombinant proteins, and it is important to optimize expression condition. The aim of this study was the optimization of multi-epitopic HIV-1 tat/pol/gag/env recombinant protein (HIVtop4) expression by E. coli and conjugation of purified protein to anti DEC-205 monoclonal antibody as candidate vaccine. MATERIALS AND METHODS In this study, expression was induced in BL21 (DE3) E. coli cells by optimization of induction condition, post induction incubation time, temperature and culture medium formula. Some culture mediums were used for cell culture, and isopropyl-beta-D-thiogalactopyranoside was used for induction of expression. Protein was purified by Ni-NTA column chromatography and confirmed against anti-His antibody in western-blotting. To exploit DCs properties for immunization purposes, recombinant protein chemically coupled to αDEC-205 monoclonal antibody and confirmed against anti-His antibody in western-blotting. RESULTS The optimum condition for expression was 1 mM IPTG during 4 hr cultures in 2XYT medium, and final protein produced in soluble form. Conjugation of purified protein to αDEC-205 antibody resulted in smears of protein: antibodies conjugate in different molecular weights. CONCLUSION The best cultivation condition for production of HIVtop4 protein is induction by 1 mM IPTG during 4 hr in 2XYT medium. The final concentration of purified protein was 500 µg/ml.
Collapse
Affiliation(s)
- Roghayeh Rahimi
- Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Massoumeh Ebtekar
- Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran,*Corresponding author: Massoumeh Ebtekar. Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran. Tel: +98-21-82883891; Fax: +98-21-82884555;
| | - Seyed Mohammad Moazzeni
- Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Ali Mostafaie
- Biotechnology Research Center, Kermanshah University, Kermanshah, Iran
| | - Mehdi Mahdavi
- Department of Virology, Pasteur Institute of Iran, Tehran, Iran
| |
Collapse
|
11
|
McGuire AT, Dreyer AM, Carbonetti S, Lippy A, Glenn J, Scheid JF, Mouquet H, Stamatatos L. HIV antibodies. Antigen modification regulates competition of broad and narrow neutralizing HIV antibodies. Science 2014; 346:1380-1383. [PMID: 25504724 DOI: 10.1126/science.1259206] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Some HIV-infected individuals develop broadly neutralizing antibodies (bNAbs), whereas most develop antibodies that neutralize only a narrow range of viruses (nNAbs). bNAbs, but not nNAbs, protect animals from experimental infection and are likely a key component of an effective vaccine. nNAbs and bNAbs target the same regions of the viral envelope glycoprotein (Env), but for reasons that remain unclear only nNAbs are elicited by Env immunization. We show that in contrast to germline-reverted (gl) bNAbs, glnNAbs recognized diverse recombinant Envs. Moreover, owing to binding affinity differences, nNAb B cell progenitors had an advantage in becoming activated and internalizing Env compared with bNAb B cell progenitors. We then identified an Env modification strategy that minimized the activation of nNAb B cells targeting epitopes that overlap those of bNAbs.
Collapse
Affiliation(s)
| | - Anita M Dreyer
- Seattle Biomedical Research Institute, Seattle, WA 98109, USA
| | - Sara Carbonetti
- Seattle Biomedical Research Institute, Seattle, WA 98109, USA
| | - Adriana Lippy
- Seattle Biomedical Research Institute, Seattle, WA 98109, USA
| | - Jolene Glenn
- Seattle Biomedical Research Institute, Seattle, WA 98109, USA
| | - Johannes F Scheid
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Hugo Mouquet
- Laboratory of Humoral Response to Pathogens, Department of Immunology, Institut Pasteur and CNRS-URA 1961, 75015 Paris, France
| | - Leonidas Stamatatos
- Seattle Biomedical Research Institute, Seattle, WA 98109, USA.,Department of Global Health, University of Washington, Seattle, WA 98109, USA
| |
Collapse
|
12
|
Moscoso CG, Xing L, Hui J, Hu J, Kalkhoran MB, Yenigun OM, Sun Y, Paavolainen L, Martin L, Vahlne A, Zambonelli C, Barnett SW, Srivastava IK, Cheng RH. Trimeric HIV Env provides epitope occlusion mediated by hypervariable loops. Sci Rep 2014; 4:7025. [PMID: 25395053 PMCID: PMC4231788 DOI: 10.1038/srep07025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 08/26/2014] [Indexed: 12/17/2022] Open
Abstract
Hypervariable loops of HIV-1 Env protein gp120 are speculated to play roles in the conformational transition of Env to the receptor binding-induced metastable state. Structural analysis of full-length Env-based immunogens, containing the entire V2 loop, displayed tighter association between gp120 subunits, resulting in a smaller trimeric diameter than constructs lacking V2. A prominent basal quaternary location of V2 and V3′ that challenges previous reports would facilitate gp41-independent gp120-gp120 interactions and suggests a quaternary mechanism of epitope occlusion facilitated by hypervariable loops. Deletion of V2 resulted in dramatic exposure of basal, membrane-proximal gp41 epitopes, consistent with its predicted basal location. The structural features of HIV-1 Env characterized here provide grounds for a paradigm shift in loop exposure and epitope occlusion, while providing substantive rationale for epitope display required for elicitation of broadly neutralizing antibodies, as well as substantiating previous pertinent literature disregarded in recent reports.
Collapse
Affiliation(s)
- Carlos G Moscoso
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Li Xing
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Jinwen Hui
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Jeffrey Hu
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | | | - Onur M Yenigun
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Yide Sun
- Novartis Vaccines and Diagnostics Inc., 45 Sydney Street, Cambridge, MA 02139
| | - Lassi Paavolainen
- Department of Biological and Environmental Science/Nanoscience Center, University of Jyväskylä, FI-40351 Jyväskylä, Finland
| | - Loïc Martin
- Commissariat à l'énergie atomique et aux énergies alternatives, Institut de Biologie et Technologies de Saclay, Service d'Ingénierie Moléculaire des Protéines, Gif-sur-Yvette F-91191, France
| | - Anders Vahlne
- Karolinska Institutet, Structural Virology, Clinical Microbiology/University Hospital, 171 77 Stockholm, Sweden
| | - Carlo Zambonelli
- Novartis Vaccines and Diagnostics Inc., 45 Sydney Street, Cambridge, MA 02139
| | - Susan W Barnett
- Novartis Vaccines and Diagnostics Inc., 45 Sydney Street, Cambridge, MA 02139
| | | | - R Holland Cheng
- 1] Department of Molecular and Cellular Biology, University of California, Davis, CA 95616 [2] Karolinska Institutet, Structural Virology, Clinical Microbiology/University Hospital, 171 77 Stockholm, Sweden
| |
Collapse
|
13
|
Rao M, Peachman KK, Kim J, Gao G, Alving CR, Michael NL, Rao VB. HIV-1 variable loop 2 and its importance in HIV-1 infection and vaccine development. Curr HIV Res 2014; 11:427-38. [PMID: 24191938 DOI: 10.2174/1570162x113116660064] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2013] [Revised: 05/24/2013] [Accepted: 06/13/2013] [Indexed: 12/30/2022]
Abstract
A vaccine that can prevent the transmission of HIV-1 at the site of exposure to the host is one of the best hopes to control the HIV-1 pandemic. The trimeric envelope spike consisting of heterodimers, gp120 and gp41, is essential for virus entry and thus has been a key target for HIV-1 vaccine development. However, it has been extremely difficult to identify the types of antibodies required to block the transmission of various HIV-1 strains and the immunogens that can elicit such antibodies due to the high genetic diversity of the HIV-1 envelope. The modest efficacy of the gp120 HIV-1 vaccine used in the RV144 Thai trial, including the studies on the immune correlates of protection, and the discovery of vaccine-induced immune responses to certain signature regions of the envelope have shown that the gp120 variable loop 2 (V2) is an important region. Since there is evidence that the V2 region interacts with the integrin α4β7 receptor of the host cell, and that this interaction might be important for virus capture, induction of antibodies against V2 loop could be postulated as one of the mechanisms to prevent the acquisition of HIV-1. Immunogens that can induce these antibodies should therefore be taken into consideration when designing HIV-1 vaccine formulations.
Collapse
Affiliation(s)
- Mangala Rao
- Laboratory of Adjuvant and Antigen Research, USMHRP at the Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Rm 2A08, Sliver Spring, MD 20910, USA.
| | | | | | | | | | | | | |
Collapse
|
14
|
Evans MC, Phung P, Paquet AC, Parikh A, Petropoulos CJ, Wrin T, Haddad M. Predicting HIV-1 broadly neutralizing antibody epitope networks using neutralization titers and a novel computational method. BMC Bioinformatics 2014; 15:77. [PMID: 24646213 PMCID: PMC3999910 DOI: 10.1186/1471-2105-15-77] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 03/03/2014] [Indexed: 11/26/2022] Open
Abstract
Background Recent efforts in HIV-1 vaccine design have focused on immunogens that evoke potent neutralizing antibody responses to a broad spectrum of viruses circulating worldwide. However, the development of effective vaccines will depend on the identification and characterization of the neutralizing antibodies and their epitopes. We developed bioinformatics methods to predict epitope networks and antigenic determinants using structural information, as well as corresponding genotypes and phenotypes generated by a highly sensitive and reproducible neutralization assay. 282 clonal envelope sequences from a multiclade panel of HIV-1 viruses were tested in viral neutralization assays with an array of broadly neutralizing monoclonal antibodies (mAbs: b12, PG9,16, PGT121 - 128, PGT130 - 131, PGT135 - 137, PGT141 - 145, and PGV04). We correlated IC50 titers with the envelope sequences, and used this information to predict antibody epitope networks. Structural patches were defined as amino acid groups based on solvent-accessibility, radius, atomic depth, and interaction networks within 3D envelope models. We applied a boosted algorithm consisting of multiple machine-learning and statistical models to evaluate these patches as possible antibody epitope regions, evidenced by strong correlations with the neutralization response for each antibody. Results We identified patch clusters with significant correlation to IC50 titers as sites that impact neutralization sensitivity and therefore are potentially part of the antibody binding sites. Predicted epitope networks were mostly located within the variable loops of the envelope glycoprotein (gp120), particularly in V1/V2. Site-directed mutagenesis experiments involving residues identified as epitope networks across multiple mAbs confirmed association of these residues with loss or gain of neutralization sensitivity. Conclusions Computational methods were implemented to rapidly survey protein structures and predict epitope networks associated with response to individual monoclonal antibodies, which resulted in the identification and deeper understanding of immunological hotspots targeted by broadly neutralizing HIV-1 antibodies.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Mojgan Haddad
- Monogram Biosciences Inc,, 345 Oyster Point Blvd,, South San Francisco, CA 94080, USA.
| |
Collapse
|
15
|
Xu K, Rockx B, Xie Y, DeBuysscher BL, Fusco DL, Zhu Z, Chan YP, Xu Y, Luu T, Cer RZ, Feldmann H, Mokashi V, Dimitrov DS, Bishop-Lilly KA, Broder CC, Nikolov DB. Crystal structure of the Hendra virus attachment G glycoprotein bound to a potent cross-reactive neutralizing human monoclonal antibody. PLoS Pathog 2013; 9:e1003684. [PMID: 24130486 PMCID: PMC3795035 DOI: 10.1371/journal.ppat.1003684] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 08/20/2013] [Indexed: 12/25/2022] Open
Abstract
The henipaviruses, represented by Hendra (HeV) and Nipah (NiV) viruses are highly pathogenic zoonotic paramyxoviruses with uniquely broad host tropisms responsible for repeated outbreaks in Australia, Southeast Asia, India and Bangladesh. The high morbidity and mortality rates associated with infection and lack of licensed antiviral therapies make the henipaviruses a potential biological threat to humans and livestock. Henipavirus entry is initiated by the attachment of the G envelope glycoprotein to host cell membrane receptors. Previously, henipavirus-neutralizing human monoclonal antibodies (hmAb) have been isolated using the HeV-G glycoprotein and a human naïve antibody library. One cross-reactive and receptor-blocking hmAb (m102.4) was recently demonstrated to be an effective post-exposure therapy in two animal models of NiV and HeV infection, has been used in several people on a compassionate use basis, and is currently in development for use in humans. Here, we report the crystal structure of the complex of HeV-G with m102.3, an m102.4 derivative, and describe NiV and HeV escape mutants. This structure provides detailed insight into the mechanism of HeV and NiV neutralization by m102.4, and serves as a blueprint for further optimization of m102.4 as a therapeutic agent and for the development of entry inhibitors and vaccines. Since their initial emergence, henipaviruses have continued to cause spillover events in both human and livestock populations, posing significant biothreats. Currently there are no licensed or approved therapies for treatment of henipavirus infection and the human case mortality rates average >70%. We used X-ray crystallography to determine the high-resolution structures of the Hendra virus G glycoprotein in complex with a cross-reactive neutralizing human monoclonal antibody. The structures provide detailed insight into the mechanism of HeV and NiV neutralization by this potent and clinically-relevant human monoclonal antibody that is currently in development for use in humans. This monoclonal antibody was recently shown to be an effective post-exposure therapy in non-human models of lethal Hendra virus infection. Indeed, it has already been used in four people on a compassionate use request, three in Australia and one in the United States, as a therapeutic agent. Furthermore, we identified and characterized two escape mutants generated in vitro and evaluated their mechanism of escape. Our results serve as a blueprint for further optimization of this antibody and for the development of novel entry inhibitors and vaccines. This report also supports the additional pre-clinical data required for eventual licensure by detailing the antibody's mechanism of henipavirus neutralization.
Collapse
Affiliation(s)
- Kai Xu
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
| | - Barry Rockx
- Sealy Center for Vaccine Development, Departments of Pathology and Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Yihu Xie
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
| | - Blair L. DeBuysscher
- Laboratory of Virology, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, Montana, United States of America
- Division of Biological Sciences and the University of Montana, Missoula, Montana, United States of America
| | - Deborah L. Fusco
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, United States of America
| | - Zhongyu Zhu
- Protein Interactions Group, CCRNP, CCR, Frederick National Laboratory for Cancer Research, National Institutes of Health, Frederick, Maryland, United States of America
| | - Yee-Peng Chan
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, United States of America
| | - Yan Xu
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
| | - Truong Luu
- Naval Medical Research Center, NMRC-Frederick, Fort Detrick, Maryland, United States of America
- Henry M. Jackson Foundation, Bethesda, Maryland, United States of America
| | - Regina Z. Cer
- Naval Medical Research Center, NMRC-Frederick, Fort Detrick, Maryland, United States of America
- Henry M. Jackson Foundation, Bethesda, Maryland, United States of America
| | - Heinz Feldmann
- Laboratory of Virology, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, Montana, United States of America
- Department of Medical Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Vishwesh Mokashi
- Naval Medical Research Center, NMRC-Frederick, Fort Detrick, Maryland, United States of America
| | - Dimiter S. Dimitrov
- Protein Interactions Group, CCRNP, CCR, Frederick National Laboratory for Cancer Research, National Institutes of Health, Frederick, Maryland, United States of America
| | - Kimberly A. Bishop-Lilly
- Naval Medical Research Center, NMRC-Frederick, Fort Detrick, Maryland, United States of America
- Henry M. Jackson Foundation, Bethesda, Maryland, United States of America
| | - Christopher C. Broder
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, United States of America
| | - Dimitar B. Nikolov
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
- * E-mail:
| |
Collapse
|
16
|
Horlick RA, Macomber JL, Bowers PM, Neben TY, Tomlinson GL, Krapf IP, Dalton JL, Verdino P, King DJ. Simultaneous surface display and secretion of proteins from mammalian cells facilitate efficient in vitro selection and maturation of antibodies. J Biol Chem 2013; 288:19861-9. [PMID: 23689374 DOI: 10.1074/jbc.m113.452482] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
A mammalian expression system has been developed that permits simultaneous cell surface display and secretion of the same protein through alternate splicing of pre-mRNA. This enables a flexible system for in vitro protein evolution in mammalian cells where the displayed protein phenotype remains linked to genotype, but with the advantage of soluble protein also being produced without the requirement for any further recloning to allow a wide range of assays, including biophysical and cell-based functional assays, to be used during the selection process. This system has been used for the simultaneous surface presentation and secretion of IgG during antibody discovery and maturation. Presentation and secretion of monomeric Fab can also be achieved to minimize avidity effects. Manipulation of the splice donor site sequence enables control of the relative amounts of cell surface and secreted antibody. Multi-domain proteins may be presented and secreted in different formats to enable flexibility in experimental design, and secreted proteins may be produced with epitope tags to facilitate high-throughput testing. This system is particularly useful in the context of in situ mutagenesis, as in the case of in vitro somatic hypermutation.
Collapse
|
17
|
Kwong PD, Mascola JR, Nabel GJ. Rational design of vaccines to elicit broadly neutralizing antibodies to HIV-1. Cold Spring Harb Perspect Med 2013; 1:a007278. [PMID: 22229123 DOI: 10.1101/cshperspect.a007278] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The development of a highly effective AIDS vaccine will likely depend on success in designing immunogens that elicit broadly neutralizing antibodies to naturally circulating strains of HIV-1. Although the antibodies induced after natural infection with HIV-1 are often directed to strain-specific or nonneutralizing determinants, it is now evident that 10%-25% of HIV-infected individuals generate neutralizing antibody responses of considerable breadth. In the past, only four broadly neutralizing monoclonal antibodies had been defined, but more than a dozen monoclonal antibodies of substantial breadth have more recently been isolated. An understanding of their recognition sites, the structural basis of their interaction with the HIV Env, and their development pathways provides new opportunities to design vaccine candidates that will elicit broadly protective antibodies against this virus.
Collapse
Affiliation(s)
- Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | | | | |
Collapse
|
18
|
Neutralizing antibody responses in macaques induced by human immunodeficiency virus type 1 monovalent or trivalent envelope glycoproteins. PLoS One 2013; 8:e59803. [PMID: 23533650 PMCID: PMC3606129 DOI: 10.1371/journal.pone.0059803] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 02/19/2013] [Indexed: 01/16/2023] Open
Abstract
A major goal of efforts to develop a vaccine to prevent HIV-1 infection is induction of broadly cross-reactive neutralizing antibodies (bcnAb). In previous studies we have demonstrated induction of neutralizing antibodies that did cross-react among multiple primary and laboratory strains of HIV-1, but neutralized with limited potency. In the present study we tested the hypothesis that immunization with multiple HIV-1 envelope glycoproteins (Envs) would result in a more potent and cross-reactive neutralizing response. One Env, CM243(N610Q), was selected on the basis of studies of the effects of single and multiple mutations of the four gp41 glycosylation sites. The other two Envs included R2 (subtype B) and 14/00/4 (subtype F), both of which were obtained from donors with bcnAb. Rhesus monkeys were immunized using a prime boost regimen as in previous studies. Individual groups of monkeys were immunized with either one of the three Envs or all three. The single N610Q and N615Q mutations of CM243 Env did not disrupt protein secretion, processing into, or reactivity with mAbs, unlike other single or multiple deglycosylation mutations. In rabbit studies the N610Q mutation alone or in combination was associated with an enhanced neutralizing response against homologous and heterologous subtype E viruses. In the subsequent monkey study the response induced by the R2 Env regimen was equivalent to the trivalent regimen and superior to the other monovalent regimens against the virus panel used for testing. The 14/00/4 Env induced responses superior to CM243(N610Q). The results indicate that elimination of the glycosylation site near the gp41 loop results in enhanced immunogenicity, but that immunization of monkeys with these three distinct Envs was not more immunogenic than with one.
Collapse
|
19
|
Murphy MK, Yue L, Pan R, Boliar S, Sethi A, Tian J, Pfafferot K, Karita E, Allen SA, Cormier E, Goepfert PA, Borrow P, Robinson JE, Gnanakaran S, Hunter E, Kong XP, Derdeyn CA. Viral escape from neutralizing antibodies in early subtype A HIV-1 infection drives an increase in autologous neutralization breadth. PLoS Pathog 2013; 9:e1003173. [PMID: 23468623 PMCID: PMC3585129 DOI: 10.1371/journal.ppat.1003173] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 12/19/2012] [Indexed: 01/07/2023] Open
Abstract
Antibodies that neutralize (nAbs) genetically diverse HIV-1 strains have been recovered from a subset of HIV-1 infected subjects during chronic infection. Exact mechanisms that expand the otherwise narrow neutralization capacity observed during early infection are, however, currently undefined. Here we characterized the earliest nAb responses in a subtype A HIV-1 infected Rwandan seroconverter who later developed moderate cross-clade nAb breadth, using (i) envelope (Env) glycoproteins from the transmitted/founder virus and twenty longitudinal nAb escape variants, (ii) longitudinal autologous plasma, and (iii) autologous monoclonal antibodies (mAbs). Initially, nAbs targeted a single region of gp120, which flanked the V3 domain and involved the alpha2 helix. A single amino acid change at one of three positions in this region conferred early escape. One immunoglobulin heavy chain and two light chains recovered from autologous B cells comprised two mAbs, 19.3H-L1 and 19.3H-L3, which neutralized the founder Env along with one or three of the early escape variants carrying these mutations, respectively. Neither mAb neutralized later nAb escape or heterologous Envs. Crystal structures of the antigen-binding fragments (Fabs) revealed flat epitope contact surfaces, where minimal light chain mutation in 19.3H-L3 allowed for additional antigenic interactions. Resistance to mAb neutralization arose in later Envs through alteration of two glycans spatially adjacent to the initial escape signatures. The cross-neutralizing nAbs that ultimately developed failed to target any of the defined V3-proximal changes generated during the first year of infection in this subject. Our data demonstrate that this subject's first recognized nAb epitope elicited strain-specific mAbs, which incrementally acquired autologous breadth, and directed later B cell responses to target distinct portions of Env. This immune re-focusing could have triggered the evolution of cross-clade antibodies and suggests that exposure to a specific sequence of immune escape variants might promote broad humoral responses during HIV-1 infection.
Collapse
Affiliation(s)
- Megan K. Murphy
- Immunology and Molecular Pathogenesis Graduate Program, Emory University, Atlanta, Georgia, United States of America
- Emory Vaccine Center at Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
| | - Ling Yue
- Emory Vaccine Center at Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
| | - Ruimin Pan
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, United States of America
| | - Saikat Boliar
- Emory Vaccine Center at Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
| | - Anurag Sethi
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Jianhui Tian
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Katja Pfafferot
- Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Susan A. Allen
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia, United States of America
- Departments of Epidemiology and Global Health, Emory University, Atlanta, Georgia, United States of America
| | - Emmanuel Cormier
- International AIDS Vaccine Initiative, Human Immunology Laboratory, Imperial College, London, United Kingdom
| | - Paul A. Goepfert
- Departments of Medicine and Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Persephone Borrow
- Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - James E. Robinson
- Department of Pediatrics, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - S. Gnanakaran
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Eric Hunter
- Emory Vaccine Center at Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia, United States of America
| | - Xiang-Peng Kong
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, United States of America
| | - Cynthia A. Derdeyn
- Emory Vaccine Center at Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia, United States of America
- * E-mail:
| |
Collapse
|
20
|
Zolla-Pazner S, deCamp AC, Cardozo T, Karasavvas N, Gottardo R, Williams C, Morris DE, Tomaras G, Rao M, Billings E, Berman P, Shen X, Andrews C, O'Connell RJ, Ngauy V, Nitayaphan S, de Souza M, Korber B, Koup R, Bailer RT, Mascola JR, Pinter A, Montefiori D, Haynes BF, Robb ML, Rerks-Ngarm S, Michael NL, Gilbert PB, Kim JH. Analysis of V2 antibody responses induced in vaccinees in the ALVAC/AIDSVAX HIV-1 vaccine efficacy trial. PLoS One 2013; 8:e53629. [PMID: 23349725 PMCID: PMC3547933 DOI: 10.1371/journal.pone.0053629] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 11/23/2012] [Indexed: 12/18/2022] Open
Abstract
The RV144 clinical trial of a prime/boost immunizing regimen using recombinant canary pox (ALVAC-HIV) and two gp120 proteins (AIDSVAX B and E) was previously shown to have a 31.2% efficacy rate. Plasma specimens from vaccine and placebo recipients were used in an extensive set of assays to identify correlates of HIV-1 infection risk. Of six primary variables that were studied, only one displayed a significant inverse correlation with risk of infection: the antibody (Ab) response to a fusion protein containing the V1 and V2 regions of gp120 (gp70-V1V2). This finding prompted a thorough examination of the results generated with the complete panel of 13 assays measuring various V2 Abs in the stored plasma used in the initial pilot studies and those used in the subsequent case-control study. The studies revealed that the ALVAC-HIV/AIDSVAX vaccine induced V2-specific Abs that cross-react with multiple HIV-1 subgroups and recognize both conformational and linear epitopes. The conformational epitope was present on gp70-V1V2, while the predominant linear V2 epitope mapped to residues 165–178, immediately N-terminal to the putative α4β7 binding motif in the mid-loop region of V2. Odds ratios (ORs) were calculated to compare the risk of infection with data from 12 V2 assays, and in 11 of these, the ORs were ≤1, reaching statistical significance for two of the variables: Ab responses to gp70-V1V2 and to overlapping V2 linear peptides. It remains to be determined whether anti-V2 Ab responses were directly responsible for the reduced infection rate in RV144 and whether anti-V2 Abs will prove to be important with other candidate HIV vaccines that show efficacy, however, the results support continued dissection of Ab responses to the V2 region which may illuminate mechanisms of protection from HIV-1 infection and may facilitate the development of an effective HIV-1 vaccine.
Collapse
Affiliation(s)
- Susan Zolla-Pazner
- Research Service, Veterans Affairs Medical Center, New York, New York, United States of America.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Viana IFT, Soares TA, Lima LFO, Marques ETA, Krieger MA, Dhalia R, Lins RD. De novo design of immunoreactive conformation-specific HIV-1 epitopes based on Top7 scaffold. RSC Adv 2013. [DOI: 10.1039/c3ra41562g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|
22
|
Karasavvas N, Billings E, Rao M, Williams C, Zolla-Pazner S, Bailer RT, Koup RA, Madnote S, Arworn D, Shen X, Tomaras GD, Currier JR, Jiang M, Magaret C, Andrews C, Gottardo R, Gilbert P, Cardozo TJ, Rerks-Ngarm S, Nitayaphan S, Pitisuttithum P, Kaewkungwal J, Paris R, Greene K, Gao H, Gurunathan S, Tartaglia J, Sinangil F, Korber BT, Montefiori DC, Mascola JR, Robb ML, Haynes BF, Ngauy V, Michael NL, Kim JH, de Souza, for the MOPH TAVEG Collab MS. The Thai Phase III HIV Type 1 Vaccine trial (RV144) regimen induces antibodies that target conserved regions within the V2 loop of gp120. AIDS Res Hum Retroviruses 2012; 28:1444-57. [PMID: 23035746 DOI: 10.1089/aid.2012.0103] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The Thai Phase III clinical trial (RV144) showed modest efficacy in preventing HIV-1 acquisition. Plasma collected from HIV-1-uninfected trial participants completing all injections with ALVAC-HIV (vCP1521) prime and AIDSVAX B/E boost were tested for antibody responses against HIV-1 gp120 envelope (Env). Peptide microarray analysis from six HIV-1 subtypes and group M consensus showed that vaccination induced antibody responses to the second variable (V2) loop of gp120 of multiple subtypes. We further evaluated V2 responses by ELISA and surface plasmon resonance using cyclic (Cyc) and linear V2 loop peptides. Thirty-one of 32 vaccine recipients tested (97%) had antibody responses against Cyc V2 at 2 weeks postimmunization with a reciprocal geometric mean titer (GMT) of 1100 (range: 200-3200). The frequency of detecting plasma V2 antibodies declined to 19% at 28 weeks post-last injection (GMT: 110, range: 100-200). Antibody responses targeted the mid-region of the V2 loop that contains conserved epitopes and has the amino acid sequence KQKVHALFYKLDIVPI (HXB2 Numbering sequence 169-184). Valine at position 172 was critical for antibody binding. The frequency of V3 responses at 2 weeks postimmunization was modest (18/32, 56%) with a GMT of 185 (range: 100-800). In contrast, naturally infected HIV-1 individuals had a lower frequency of antibody responses to V2 (10/20, 50%; p=0.003) and a higher frequency of responses to V3 (19/20, 95%), with GMTs of 400 (range: 100-3200) and 3570 (range: 200-12,800), respectively. RV144 vaccination induced antibodies that targeted a region of the V2 loop that contains conserved epitopes. Early HIV-1 transmission events involve V2 loop interactions, raising the possibility that anti-V2 antibodies in RV144 may have contributed to viral inhibition.
Collapse
Affiliation(s)
- Nicos Karasavvas
- Department of Retrovirology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand
| | - Erik Billings
- U.S. Military HIV Research Program (MHRP), Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, Maryland
| | - Mangala Rao
- USMHRP, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Constance Williams
- Department of Pathology and Pharmacology, NYU School of Medicine, New York, New York
| | - Susan Zolla-Pazner
- Department of Pathology and Pharmacology, NYU School of Medicine, New York, New York
- Veterans Affairs Harbor Healthcare System, New York, New York
| | - Robert T. Bailer
- Immunology Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Richard A. Koup
- Immunology Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Sirinan Madnote
- Department of Retrovirology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand
| | - Duangnapa Arworn
- Department of Retrovirology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand
| | - Xiaoying Shen
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina
| | - Georgia D. Tomaras
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina
| | - Jeffrey R. Currier
- U.S. Military HIV Research Program (MHRP), Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, Maryland
| | - Mike Jiang
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Craig Magaret
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Charla Andrews
- U.S. Military HIV Research Program (MHRP), Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, Maryland
| | - Raphael Gottardo
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Peter Gilbert
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Timothy J. Cardozo
- Department of Pathology and Pharmacology, NYU School of Medicine, New York, New York
| | | | - Sorachai Nitayaphan
- Royal Thai Army Component, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok Thailand
| | - Punnee Pitisuttithum
- Vaccine Trial Center and Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Jaranit Kaewkungwal
- Center of Excellence for Biomedical and Public Health Informatics (BIOPHICS), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Robert Paris
- USMHRP, Walter Reed Army Institute of Research, Silver Spring, Maryland
- Walter Reed National Military Medical Center, Bethesda, Maryland
| | - Kelli Greene
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Hongmei Gao
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | | | | | - Faruk Sinangil
- Global Solutions for Infectious Diseases, South San Francisco, California
| | - Bette T. Korber
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico
| | - David C. Montefiori
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - John R. Mascola
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Merlin L. Robb
- U.S. Military HIV Research Program (MHRP), Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, Maryland
| | - Barton F. Haynes
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina
| | - Viseth Ngauy
- Department of Retrovirology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand
| | - Nelson L. Michael
- USMHRP, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Jerome H. Kim
- USMHRP, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | | | | |
Collapse
|
23
|
Role of human immunodeficiency virus type 1 envelope structure in the induction of broadly neutralizing antibodies. J Virol 2012; 86:13152-63. [PMID: 23015715 DOI: 10.1128/jvi.01110-12] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Very soon after the discovery of neutralizing antibodies (NAbs) toward human immunodeficiency virus type 1 (HIV-1) infection, it became apparent that characterization of these NAbs would be an important step in finding a cure for or a vaccine to eradicate HIV-1. Since the initial description of broadly cross-clade NAbs naturally produced in HIV-1 patients, numerous studies have described new viral targets for these antibodies. More recently, studies concerning new groups of patients able to control their viremia, such as long-term nonprogressors (LTNPs) or elite controllers, have described the generation of numerous envelope-targeted NAbs. Recent studies have marked a new stage in research on NAbs with the description of antibodies obtained from a worldwide screening of HIV-positive patients. These studies have permitted the discovery of NAb families with great potential for both neutralization and neutralization breadth, such as PG, PGT, CH, and highly active agonistic anti-CD4 binding site antibodies (HAADs), of which VRC01 and its variants are members. These antibodies are able to neutralize more than 80% of circulating strains without any autoreactivity and can be rapidly integrated into clinical trials in order to test their protective potential. In this review, we will focus on new insights into HIV-1 envelope structure and their implications for the generation of potent NAbs.
Collapse
|
24
|
Bonsignori M, Alam SM, Liao HX, Verkoczy L, Tomaras GD, Haynes BF, Moody MA. HIV-1 antibodies from infection and vaccination: insights for guiding vaccine design. Trends Microbiol 2012; 20:532-9. [PMID: 22981828 DOI: 10.1016/j.tim.2012.08.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 08/15/2012] [Accepted: 08/20/2012] [Indexed: 11/30/2022]
Abstract
Attempts to formulate a protective HIV-1 vaccine through classic vaccine design strategies have not been successful. Elicitation of HIV-1-specific broadly neutralizing antibodies (bnAbs) at high titers that are present before exposure might be required to achieve protection. Recently, the application of new technologies has facilitated the study of clonal lineages of HIV-1 envelope (Env) antibodies, which have provided insights into HIV-1 antibody development during infection and upon vaccination. Strategies are being developed for the analysis of infection and vaccine candidate-induced antibodies, their gene usage, and their maturation pathways such that this information can be used to attempt to guide rational vaccine design.
Collapse
Affiliation(s)
- Mattia Bonsignori
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA.
| | | | | | | | | | | | | |
Collapse
|
25
|
Van Regenmortel MHV. Basic research in HIV vaccinology is hampered by reductionist thinking. Front Immunol 2012; 3:194. [PMID: 22787464 PMCID: PMC3391733 DOI: 10.3389/fimmu.2012.00194] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 06/21/2012] [Indexed: 01/05/2023] Open
Abstract
This review describes the structure-based reverse vaccinology approach aimed at developing vaccine immunogens capable of inducing antibodies that broadly neutralize HIV-1. Some basic principles of protein immunochemistry are reviewed and the implications of the extensive polyspecificity of antibodies for vaccine development are underlined. Although it is natural for investigators to want to know the cause of an effective immunological intervention, the classic notion of causality is shown to have little explanatory value for a system as complex as the immune system, where any observed effect always results from many interactions between a large number of components. Causal explanations are reductive because a single factor is singled out for attention and given undue explanatory weight on its own. Other examples of the negative impact of reductionist thinking on HIV vaccine development are discussed. These include (1) the failure to distinguish between the chemical nature of antigenicity and the biological nature of immunogenicity, (2) the belief that when an HIV-1 epitope is reconstructed by rational design to better fit a neutralizing monoclonal antibody (nMab), this will produce an immunogen able to elicit Abs with the same neutralizing capacity as the Ab used as template for designing the antigen, and (3) the belief that protection against infection can be analyzed at the level of individual molecular interactions although it has meaning only at the level of an entire organism. The numerous unsuccessful strategies that have been used to design HIV-1 vaccine immunogens are described and it is suggested that the convergence of so many negative experimental results justifies the conclusion that reverse vaccinology is unlikely to lead to the development of a preventive HIV-1 vaccine. Immune correlates of protection in vaccines have not yet been identified because this will become feasible only retrospectively once an effective vaccine exists. The finding that extensive antibody affinity maturation is needed to obtain mature anti-HIV-1 Abs endowed with a broad neutralizing capacity explains why antigens designed to fit matured Mabs are not effective vaccine immunogens since these are administered to naive recipients who possess only B-cell receptors corresponding to the germline version of the matured Abs.
Collapse
Affiliation(s)
- Marc H. V. Van Regenmortel
- Stellenbosch Institute of Advanced Study, Wallenberg Research Center at Stellenbosch University,Stellenbosch, South Africa
| |
Collapse
|
26
|
Human peripheral blood antibodies with long HCDR3s are established primarily at original recombination using a limited subset of germline genes. PLoS One 2012; 7:e36750. [PMID: 22590602 PMCID: PMC3348910 DOI: 10.1371/journal.pone.0036750] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 04/07/2012] [Indexed: 12/27/2022] Open
Abstract
A number of antibodies that efficiently neutralize microbial targets contain long heavy chain complementarity determining region 3 (HCDR3) loops. For HIV, several of the most broad and potently neutralizing antibodies have exceptionally long HCDR3s. Two broad potently neutralizing HIV-specific antibodies, PG9 and PG16, exhibit secondary structure. Two other long HCDR3 antibodies, 2F5 and 4E10, protect against mucosal challenge with SHIV. Induction of such long HCDR3 antibodies may be critical to the design of an effective vaccine strategy for HIV and other pathogens, however it is unclear at present how to induce such antibodies. Here, we present genetic evidence that human peripheral blood antibodies containing long HCDR3s are not primarily generated by insertions introduced during the somatic hypermutation process. Instead, they are typically formed by processes occurring as part of the original recombination event. Thus, the response of B cells encoding antibodies with long HCDR3s results from selection of unusual clones from the naïve repertoire rather than through accumulation of insertions. These antibodies typically use a small subset of D and J gene segments that are particularly suited to encoding long HCDR3s, resulting in the incorporation of highly conserved genetic elements in the majority of antibody sequences encoding long HCDR3s.
Collapse
|
27
|
B-cell-lineage immunogen design in vaccine development with HIV-1 as a case study. Nat Biotechnol 2012; 30:423-33. [PMID: 22565972 DOI: 10.1038/nbt.2197] [Citation(s) in RCA: 380] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Failure of immunization with the HIV-1 envelope to induce broadly neutralizing antibodies against conserved epitopes is a major barrier to producing a preventive HIV-1 vaccine. Broadly neutralizing monoclonal antibodies (BnAbs) from those subjects who do produce them after years of chronic HIV-1 infection have one or more unusual characteristics, including polyreactivity for host antigens, extensive somatic hypermutation and long, variable heavy-chain third complementarity-determining regions, factors that may limit their expression by host immunoregulatory mechanisms. The isolation of BnAbs from HIV-1-infected subjects and the use of computationally derived clonal lineages as templates provide a new path for HIV-1 vaccine immunogen design. This approach, which should be applicable to many infectious agents, holds promise for the construction of vaccines that can drive B cells along rare but desirable maturation pathways.
Collapse
|
28
|
Haynes BF, Gilbert PB, McElrath MJ, Zolla-Pazner S, Tomaras GD, Alam SM, Evans DT, Montefiori DC, Karnasuta C, Sutthent R, Liao HX, DeVico AL, Lewis GK, Williams C, Pinter A, Fong Y, Janes H, DeCamp A, Huang Y, Rao M, Billings E, Karasavvas N, Robb ML, Ngauy V, de Souza MS, Paris R, Ferrari G, Bailer RT, Soderberg KA, Andrews C, Berman PW, Frahm N, De Rosa SC, Alpert MD, Yates NL, Shen X, Koup RA, Pitisuttithum P, Kaewkungwal J, Nitayaphan S, Rerks-Ngarm S, Michael NL, Kim JH. Immune-correlates analysis of an HIV-1 vaccine efficacy trial. N Engl J Med 2012; 366:1275-86. [PMID: 22475592 PMCID: PMC3371689 DOI: 10.1056/nejmoa1113425] [Citation(s) in RCA: 1517] [Impact Index Per Article: 126.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND In the RV144 trial, the estimated efficacy of a vaccine regimen against human immunodeficiency virus type 1 (HIV-1) was 31.2%. We performed a case-control analysis to identify antibody and cellular immune correlates of infection risk. METHODS In pilot studies conducted with RV144 blood samples, 17 antibody or cellular assays met prespecified criteria, of which 6 were chosen for primary analysis to determine the roles of T-cell, IgG antibody, and IgA antibody responses in the modulation of infection risk. Assays were performed on samples from 41 vaccinees who became infected and 205 uninfected vaccinees, obtained 2 weeks after final immunization, to evaluate whether immune-response variables predicted HIV-1 infection through 42 months of follow-up. RESULTS Of six primary variables, two correlated significantly with infection risk: the binding of IgG antibodies to variable regions 1 and 2 (V1V2) of HIV-1 envelope proteins (Env) correlated inversely with the rate of HIV-1 infection (estimated odds ratio, 0.57 per 1-SD increase; P=0.02; q=0.08), and the binding of plasma IgA antibodies to Env correlated directly with the rate of infection (estimated odds ratio, 1.54 per 1-SD increase; P=0.03; q=0.08). Neither low levels of V1V2 antibodies nor high levels of Env-specific IgA antibodies were associated with higher rates of infection than were found in the placebo group. Secondary analyses suggested that Env-specific IgA antibodies may mitigate the effects of potentially protective antibodies. CONCLUSIONS This immune-correlates study generated the hypotheses that V1V2 antibodies may have contributed to protection against HIV-1 infection, whereas high levels of Env-specific IgA antibodies may have mitigated the effects of protective antibodies. Vaccines that are designed to induce higher levels of V1V2 antibodies and lower levels of Env-specific IgA antibodies than are induced by the RV144 vaccine may have improved efficacy against HIV-1 infection.
Collapse
Affiliation(s)
- Barton F Haynes
- Duke University Human Vaccine Institute and the Center for HIV/AIDS Vaccine Immunology, Duke University School of Medicine, Durham, NC 27710, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Kong L, Sattentau QJ. Antigenicity and Immunogenicity in HIV-1 Antibody-Based Vaccine Design. JOURNAL OF AIDS & CLINICAL RESEARCH 2012; S8:3. [PMID: 23227445 PMCID: PMC3515071 DOI: 10.4172/2155-6113] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Neutralizing antibodies can protect from infection by immunodeficiency viruses. However, the induction by active vaccination of antibodies that can potently neutralize a broad range of circulating virus strains is a goal not yet achieved, despite more than 2 decades of research. Here we review progress made in the field, from early empirical studies to today's rational structure-based vaccine antigen design. We discuss the existence of broadly neutralizing antibodies, their implications for epitope discovery and recent progress made in antigen design. Finally, we consider the relationship between antigenicity and immunogenicity for B cell recognition and antibody production, a major hurdle for rational vaccine design to overcome.
Collapse
Affiliation(s)
- Leopold Kong
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
- The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Quentin J Sattentau
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| |
Collapse
|
30
|
Gorny MK, Pan R, Williams C, Wang XH, Volsky B, O'Neal T, Spurrier B, Sampson JM, Li L, Seaman MS, Kong XP, Zolla-Pazner S. Functional and immunochemical cross-reactivity of V2-specific monoclonal antibodies from HIV-1-infected individuals. Virology 2012; 427:198-207. [PMID: 22402248 DOI: 10.1016/j.virol.2012.02.003] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 01/20/2012] [Accepted: 02/03/2012] [Indexed: 01/19/2023]
Abstract
The recent analysis of the first successful RV144 vaccine trial revealed that a high titer of plasma anti-V2 antibodies (Abs) correlated with a decreased risk of HIV-1 infection in vaccine recipients. To understand the mechanism of immune correlates, we studied seven anti-V2 monoclonal Abs (mAbs) developed from HIV-1 infected individuals. The V2 mAbs target conserved epitopes, including the binding site for α4β7 integrin, and are broadly cross-reactive with various gp120 proteins. Preferential usage of the VH1-69 gene by V2 mAbs may depend on selection by the same antigenic structure. Six of seven V2 mAbs weakly neutralized four to eight of the 41 pseudoviruses tested and resistance to neutralization was correlated with longer V2 domains. The data suggest the presence of shared, conserved structural elements in the V2 loop, and these can be used in the design of vaccine immunogens inducing broadly reactive Abs with anti-viral activities.
Collapse
Affiliation(s)
- Miroslaw K Gorny
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
McLellan JS, Pancera M, Carrico C, Gorman J, Julien JP, Khayat R, Louder R, Pejchal R, Sastry M, Dai K, O'Dell S, Patel N, Shahzad-ul-Hussan S, Yang Y, Zhang B, Zhou T, Zhu J, Boyington JC, Chuang GY, Diwanji D, Georgiev I, Kwon YD, Lee D, Louder MK, Moquin S, Schmidt SD, Yang ZY, Bonsignori M, Crump JA, Kapiga SH, Sam NE, Haynes BF, Burton DR, Koff WC, Walker LM, Phogat S, Wyatt R, Orwenyo J, Wang LX, Arthos J, Bewley CA, Mascola JR, Nabel GJ, Schief WR, Ward AB, Wilson IA, Kwong PD. Structure of HIV-1 gp120 V1/V2 domain with broadly neutralizing antibody PG9. Nature 2011; 480:336-43. [PMID: 22113616 PMCID: PMC3406929 DOI: 10.1038/nature10696] [Citation(s) in RCA: 696] [Impact Index Per Article: 53.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 11/04/2011] [Indexed: 01/26/2023]
Abstract
Variable regions 1 and 2 (V1/V2) of human immunodeficiency virus-1 (HIV-1) gp120 envelope glycoprotein are critical for viral evasion of antibody neutralization, and are themselves protected by extraordinary sequence diversity and N-linked glycosylation. Human antibodies such as PG9 nonetheless engage V1/V2 and neutralize 80% of HIV-1 isolates. Here we report the structure of V1/V2 in complex with PG9. V1/V2 forms a four-stranded β-sheet domain, in which sequence diversity and glycosylation are largely segregated to strand-connecting loops. PG9 recognition involves electrostatic, sequence-independent and glycan interactions: the latter account for over half the interactive surface but are of sufficiently weak affinity to avoid autoreactivity. The structures of V1/V2-directed antibodies CH04 and PGT145 indicate that they share a common mode of glycan penetration by extended anionic loops. In addition to structurally defining V1/V2, the results thus identify a paradigm of antibody recognition for highly glycosylated antigens, which-with PG9-involves a site of vulnerability comprising just two glycans and a strand.
Collapse
Affiliation(s)
- Jason S McLellan
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Spurrier B, Sampson JM, Totrov M, Li H, O'Neal T, Williams C, Robinson J, Gorny MK, Zolla-Pazner S, Kong XP. Structural analysis of human and macaque mAbs 2909 and 2.5B: implications for the configuration of the quaternary neutralizing epitope of HIV-1 gp120. Structure 2011; 19:691-9. [PMID: 21565703 DOI: 10.1016/j.str.2011.02.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 02/15/2011] [Accepted: 02/20/2011] [Indexed: 10/18/2022]
Abstract
The quaternary neutralizing epitope (QNE) of HIV-1 gp120 is preferentially expressed on the trimeric envelope spikes of intact HIV virions, and QNE-specific monoclonal antibodies (mAbs) potently neutralize HIV-1. Here, we present the crystal structures of the Fabs of human mAb 2909 and macaque mAb 2.5B. Both mAbs have long beta hairpin CDR H3 regions >20 Å in length that are each situated at the center of their respective antigen-binding sites. Computational analysis showed that the paratopes include the whole CDR H3, while additional CDR residues form shallow binding pockets. Structural modeling suggests a way to understand the configuration of QNEs and the antigen-antibody interaction for QNE mAbs. Our data will be useful in designing immunogens that may elicit potent neutralizing QNE Abs.
Collapse
Affiliation(s)
- Brett Spurrier
- Department of Biochemistry, NYU School of Medicine, New York, NY 10016, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Characterization of structural features and diversity of variable-region determinants of related quaternary epitopes recognized by human and rhesus macaque monoclonal antibodies possessing unusually potent neutralizing activities. J Virol 2011; 85:10730-40. [PMID: 21835798 DOI: 10.1128/jvi.00365-11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
A series of potently neutralizing monoclonal antibodies (MAbs) that target quaternary epitopes on the native Env trimer have recently been described. A common feature shared by these antibodies is the critical involvement of sites in both the V2 and V3 variable domains in antibody recognition. In this study the gp120 variable-region determinants were mapped for eight rhesus macaque monoclonal antibodies (RhMAbs) possessing potently neutralizing activity specific for a quaternary target in SF162 Env and compared to those originally identified for human MAb 2909. These studies showed that determinants for the epitopes defined by the RhMAbs differed in both the V2 (positions 160, 167, and 169) and V3 (positions 313 and 315) regions from 2909, and in a number of cases, from each other. Attempts to reconstitute expression of these epitopes on the cell surface by cotransfecting Envs containing either the V2 or the V3 determinant of the epitope were not successful, suggesting that these epitopes were expressed on individual protomers in a trimer-dependent manner. Several of the V2 positions found to be critical for expression of these quaternary epitopes also significantly affected exposure and neutralization sensitivity of targets in the V3 and CD4-binding domains. These results demonstrated a considerable diversity in the fine structure of this class of epitopes and further suggested a potentially important relationship between the expression of such quaternary epitopes and V1/V2-mediated masking of immunodominant epitopes.
Collapse
|
34
|
Analysis of a clonal lineage of HIV-1 envelope V2/V3 conformational epitope-specific broadly neutralizing antibodies and their inferred unmutated common ancestors. J Virol 2011; 85:9998-10009. [PMID: 21795340 DOI: 10.1128/jvi.05045-11] [Citation(s) in RCA: 341] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
V2/V3 conformational epitope antibodies that broadly neutralize HIV-1 (PG9 and PG16) have been recently described. Since an elicitation of previously known broadly neutralizing antibodies has proven elusive, the induction of antibodies with such specificity is an important goal for HIV-1 vaccine development. A critical question is which immunogens and vaccine formulations might be used to trigger and drive the development of memory B cell precursors with V2/V3 conformational epitope specificity. In this paper we identified a clonal lineage of four V2/V3 conformational epitope broadly neutralizing antibodies (CH01 to CH04) from an African HIV-1-infected broad neutralizer and inferred their common reverted unmutated ancestor (RUA) antibodies. While conformational epitope antibodies rarely bind recombinant Env monomers, a screen of 32 recombinant envelopes for binding to the CH01 to CH04 antibodies showed monoclonal antibody (MAb) binding to the E.A244 gp120 Env and to chronic Env AE.CM243; MAbs CH01 and CH02 also bound to transmitted/founder Env B.9021. CH01 to CH04 neutralized 38% to 49% of a panel of 91 HIV-1 tier 2 pseudoviruses, while the RUAs neutralized only 16% of HIV-1 isolates. Although the reverted unmutated ancestors showed restricted neutralizing activity, they retained the ability to bind to the E.A244 gp120 HIV-1 envelope with an affinity predicted to trigger B cell development. Thus, E.A244, B.9021, and AE.CM243 Envs are three potential immunogen candidates for studies aimed at defining strategies to induce V2/V3 conformational epitope-specific antibodies.
Collapse
|
35
|
Potent and broad anti-HIV-1 activity exhibited by a glycosyl-phosphatidylinositol-anchored peptide derived from the CDR H3 of broadly neutralizing antibody PG16. J Virol 2011; 85:8467-76. [PMID: 21715497 DOI: 10.1128/jvi.00520-11] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
PG9 and PG16 are two recently isolated quaternary-specific human monoclonal antibodies that neutralize 70 to 80% of circulating HIV-1 isolates. The crystal structure of PG16 shows that it contains an exceptionally long CDR H3 that forms a unique stable subdomain that towers above the antibody surface to confer fine specificity. To determine whether this unique architecture of CDR H3 itself is sufficient for epitope recognition and neutralization, we cloned CDR H3 subdomains derived from human monoclonal antibodies PG16, PG9, b12, E51, and AVF and genetically linked them to a glycosyl-phosphatidylinositol (GPI) attachment signal. Each fusion gene construct is expressed and targeted to lipid rafts of plasma membranes through a GPI anchor. Moreover, GPI-CDR H3(PG16, PG9, and E51), but not GPI-CDR H3(b12 and AVF), specifically neutralized multiple clades of HIV-1 isolates with a great degree of potency when expressed on the surface of transduced TZM-bl cells. Furthermore, GPI-anchored CDR H3(PG16), but not GPI-anchored CDR H3(AVF), specifically confers resistance to HIV-1 infection when expressed on the surface of transduced human CD4(+) T cells. Finally, the CDR H3 mutations (Y100HF, D100IA, and G7) that were previously shown to compromise the neutralization activity of antibody PG16 also abolished the neutralization activity of GPI-CDR H3(PG16). Thus, we conclude that the CDR H3 subdomain of PG16 neutralizes HIV-1 when targeted to the lipid raft of the plasma membrane of HIV-1-susceptible cells and that GPI-CDR H3 can be an alternative approach for determining whether the CDR H3 of certain antibodies alone can exert epitope recognition and neutralization.
Collapse
|
36
|
Binding interactions between soluble HIV envelope glycoproteins and quaternary-structure-specific monoclonal antibodies PG9 and PG16. J Virol 2011; 85:7095-107. [PMID: 21543501 DOI: 10.1128/jvi.00411-11] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PG9 and PG16 are antibodies isolated from a subject infected with HIV-1 and display broad anti-HIV neutralizing activities. They recognize overlapping epitopes, which are preferentially expressed on the membrane-anchored trimeric form of the HIV envelope glycoprotein (Env). PG9 and PG16 were reported not to bind to soluble mimetics of Env. The engineering of soluble Env proteins on which the PG9 and PG16 epitopes are optimally exposed will support efforts to elicit broad anti-HIV neutralizing antibodies by immunization. Here, we identified several soluble gp140 Env proteins that are recognized by PG9 and PG16, and we investigated the molecular details of those binding interactions. The IgG versions of PG9 and PG16 recognize the soluble trimeric gp140 form less efficiently than the corresponding monomeric gp140 form. In contrast, the Fab versions of PG9 and PG16 recognized the monomeric and trimeric gp140 forms with identical binding kinetics and with binding affinities similar to the high binding affinity of the anti-V3 antibody 447D to its epitope. Our data also indicate that, depending on the Env backbone, the interactions of PG9 and PG16 with gp140 may be facilitated by the presence of the gp41 ectodomain and are independent of the proper enzymatic cleavage of gp140 into gp120 and gp41. The identification of soluble Env proteins that express the PG9 and PG16 epitopes and the detailed characterization of the molecular interactions between these two antibodies and their ligands provide important and novel information that will assist in improving the engineering of future Env immunogens.
Collapse
|
37
|
Immunotypes of a quaternary site of HIV-1 vulnerability and their recognition by antibodies. J Virol 2011; 85:4578-85. [PMID: 21325411 DOI: 10.1128/jvi.02585-10] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HIV-1 is neutralized by a class of antibodies that preferentially recognize a site formed on the assembled viral spike. Such quaternary structure-specific antibodies have diverse neutralization breadths, with antibodies PG16 and PG9 able to neutralize 70 to 80% of circulating HIV-1 isolates while antibody 2909 is specific for strain SF162. We show that alteration between a rare lysine and a common N-linked glycan at position 160 of HIV-1 gp120 is primarily responsible for toggling between 2909 and PG16/PG9 neutralization sensitivity. Quaternary structure-specific antibodies appear to target antigenic variants of the same epitope, with neutralization breadth determined by the prevalence of recognized variants among circulating isolates.
Collapse
|