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Sholukh AM, Watkins JD, Vyas HK, Gupta S, Lakhashe SK, Thorat S, Zhou M, Hemashettar G, Bachler BC, Forthal DN, Villinger F, Sattentau QJ, Weiss RA, Agatic G, Corti D, Lanzavecchia A, Heeney JL, Ruprecht RM. Defense-in-depth by mucosally administered anti-HIV dimeric IgA2 and systemic IgG1 mAbs: complete protection of rhesus monkeys from mucosal SHIV challenge. Vaccine 2015; 33:2086-95. [PMID: 25769884 DOI: 10.1016/j.vaccine.2015.02.020] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 02/03/2015] [Accepted: 02/07/2015] [Indexed: 12/19/2022]
Abstract
Although IgA is the most abundantly produced immunoglobulin in humans, its role in preventing HIV-1 acquisition, which occurs mostly via mucosal routes, remains unclear. In our passive mucosal immunizations of rhesus macaques (RMs), the anti-HIV-1 neutralizing monoclonal antibody (nmAb) HGN194, given either as dimeric IgA1 (dIgA1) or dIgA2 intrarectally (i.r.), protected 83% or 17% of the RMs against i.r. simian-human immunodeficiency virus (SHIV) challenge, respectively. Data from the RV144 trial implied that vaccine-induced plasma IgA counteracted the protective effector mechanisms of IgG1 with the same epitope specificity. We thus hypothesized that mucosal dIgA2 might diminish the protection provided by IgG1 mAbs targeting the same epitope. To test our hypothesis, we administered HGN194 IgG1 intravenously (i.v.) either alone or combined with i.r. HGN194 dIgA2. We enrolled SHIV-exposed, persistently aviremic RMs protected by previously administered nmAbs; RM anti-human IgG responses were undetectable. However, low-level SIV Gag-specific proliferative T-cell responses were found. These animals resemble HIV-exposed, uninfected humans, in which local and systemic cellular immune responses have been observed. HGN194 IgG1 and dIgA2 used alone and the combination of the two neutralized the challenge virus equally well in vitro. All RMs given only i.v. HGN194 IgG1 became infected. In contrast, all RMs given HGN194 IgG1+dIgA2 were completely protected against high-dose i.r. SHIV-1157ipEL-p challenge. These data imply that combining suboptimal defenses at the mucosal and systemic levels can completely prevent virus acquisition. Consequently, active vaccination should focus on defense-in-depth, a strategy that seeks to build up defensive fall-back positions well behind the fortified frontline.
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Affiliation(s)
- Anton M Sholukh
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, TX, USA; Dana-Farber Cancer Institute, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Jennifer D Watkins
- Dana-Farber Cancer Institute, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Hemant K Vyas
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, TX, USA; Dana-Farber Cancer Institute, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Sandeep Gupta
- Division of Infectious Diseases, Department of Medicine, University of California, Irvine School of Medicine, Irvine, CA, USA
| | - Samir K Lakhashe
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, TX, USA; Dana-Farber Cancer Institute, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Swati Thorat
- Dana-Farber Cancer Institute, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Mingkui Zhou
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, TX, USA
| | | | | | - Donald N Forthal
- Division of Infectious Diseases, Department of Medicine, University of California, Irvine School of Medicine, Irvine, CA, USA
| | - Francois Villinger
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA, USA; Yerkes National Primate Research Center, Atlanta, GA, USA
| | - Quentin J Sattentau
- The Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Robin A Weiss
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK
| | | | - Davide Corti
- Humabs BioMed SA, Bellinzona 6500, Switzerland; Institute for Research in Biomedicine, Bellinzona 6500, Switzerland
| | - Antonio Lanzavecchia
- Institute for Research in Biomedicine, Bellinzona 6500, Switzerland; Eidgenoessische Technische Hochschule, Zurich CH-8093, Switzerland
| | - Jonathan L Heeney
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Ruth M Ruprecht
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, TX, USA; Southwest National Primate Research Center, San Antonio, TX, USA; Dana-Farber Cancer Institute, Boston, MA, USA; Harvard Medical School, Boston, MA, USA.
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Bachler BC, Humbert M, Lakhashe SK, Rasmussen RA, Ruprecht RM. Live-virus exposure of vaccine-protected macaques alters the anti-HIV-1 antibody repertoire in the absence of viremia. Retrovirology 2013; 10:63. [PMID: 23800339 PMCID: PMC3695773 DOI: 10.1186/1742-4690-10-63] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 06/03/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND We addressed the question whether live-virus challenges could alter vaccine-induced antibody (Ab) responses in vaccinated rhesus macaques (RMs) that completely resisted repeated exposures to R5-tropic simian-human immunodeficiency viruses encoding heterologous HIV clade C envelopes (SHIV-Cs). RESULTS We examined the Ab responses in aviremic RMs that had been immunized with a multi-component protein vaccine (multimeric HIV-1 gp160, HIV-1 Tat and SIV Gag-Pol particles) and compared anti-Env plasma Ab titers before and after repeated live-virus exposures. Although no viremia was ever detected in these animals, they showed significant increases in anti-gp140 Ab titers after they had encountered live SHIVs. When we investigated the dynamics of anti-Env Ab titers during the immunization and challenge phases further, we detected the expected, vaccine-induced increases of Ab responses about two weeks after the last protein immunization. Remarkably, these titers kept rising during the repeated virus challenges, although no viremia resulted. In contrast, in vaccinated RMs that were not exposed to virus, anti-gp140 Ab titers declined after the peak seen two weeks after the last immunization. These data suggest boosting of pre-existing, vaccine-induced Ab responses as a consequence of repeated live-virus exposures. Next, we screened polyclonal plasma samples from two of the completely protected vaccinees by peptide phage display and designed a strategy that selects for recombinant phages recognized only by Abs present after - but not before - any SHIV challenge. With this "subtractive biopanning" approach, we isolated V3 mimotopes that were only recognized after the animals had been exposed to live virus. By detailed epitope mapping of such anti-V3 Ab responses, we showed that the challenges not only boosted pre-existing binding and neutralizing Ab titers, but also induced Abs targeting neo-antigens presented by the heterologous challenge virus. CONCLUSIONS Anti-Env Ab responses induced by recombinant protein vaccination were altered by the multiple, live SHIV challenges in vaccinees that had no detectable viral loads. These data may have implications for the interpretation of "vaccine only" responses in clinical vaccine trials.
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Affiliation(s)
- Barbara C Bachler
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA 02215, USA
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Novel biopanning strategy to identify epitopes associated with vaccine protection. J Virol 2013; 87:4403-16. [PMID: 23388727 DOI: 10.1128/jvi.02888-12] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Identifying immune correlates of protection is important to develop vaccines against infectious diseases. We designed a novel, universally applicable strategy to profile the antibody (Ab) repertoire of protected vaccine recipients, using recombinant phages encoding random peptide libraries. The new approach, termed "protection-linked (PL) biopanning," probes the Ab paratopes of protected vaccinees versus those with vaccine failure. As proof of concept, we screened plasma samples from vaccinated rhesus macaques (RMs) that had completely resisted multiple mucosal challenges with R5-tropic simian-human immunodeficiency viruses (SHIVs). The animals had been immunized with a multicomponent vaccine (multimeric HIV-1 gp160, HIV-1 Tat, and SIV Gag-Pol particles). After PL biopanning, we analyzed the phagotopes selected for amino acid homologies; in addition to the expected Env mimotopes, one recurring motif reflected the neutralizing Ab epitope at the N terminus (NT) of HIV-1 Tat. Subsequent binding and functional assays indicated that anti-Tat NT Abs were present only in completely or partially protected RMs; peak viremia of the latter was inversely correlated with anti-Tat NT Ab titers. In contrast, highly viremic, unvaccinated controls did not develop detectable Abs against the same epitope. Based upon the protective effect observed in vivo, we suggest that Tat should be included in multicomponent HIV-1 vaccines. Our data highlight the power of the new PL-biopanning strategy to identify Ab responses with significant association to vaccine protection, regardless of the mechanism(s) or targets of the protective Abs. PL biopanning is also unbiased with regard to pathogens or disease model, making it a universal tool.
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