Vaccine Elicitation of High Mannose-Dependent Neutralizing Antibodies against the V3-Glycan Broadly Neutralizing Epitope in Nonhuman Primates

Publication date: 28 February 2017
Source:Cell Reports, Volume 18, Issue 9
Author(s): Kevin O. Saunders, Nathan I. Nicely, Kevin Wiehe, Mattia Bonsignori, R. Ryan Meyerhoff, Robert Parks, William E. Walkowicz, Baptiste Aussedat, Nelson R. Wu, Fangping Cai, Yusuf Vohra, Peter K. Park, Amanda Eaton, Eden P. Go, Laura L. Sutherland, Richard M. Scearce, Dan H. Barouch, Ruijun Zhang, Tarra Von Holle, R. Glenn Overman, Kara Anasti, Rogier W. Sanders, M. Anthony Moody, Thomas B. Kepler, Bette Korber, Heather Desaire, Sampa Santra, Norman L. Letvin, Gary J. Nabel, David C. Montefiori, Georgia D. Tomaras, Hua-Xin Liao, S. Munir Alam, Samuel J. Danishefsky, Barton F. Haynes
Induction of broadly neutralizing antibodies (bnAbs) that target HIV-1 envelope (Env) is a goal of HIV-1 vaccine development. A bnAb target is the Env third variable loop (V3)-glycan site. To determine whether immunization could induce antibodies to the V3-glycan bnAb binding site, we repetitively immunized macaques over a 4-year period with an Env expressing V3-high mannose glycans. Env immunizations elicited plasma antibodies that neutralized HIV-1 expressing only high-mannose glycans—a characteristic shared by early bnAb B cell lineage members. A rhesus recombinant monoclonal antibody from a vaccinated macaque bound to the V3-glycan site at the same amino acids as broadly neutralizing antibodies. A structure of the antibody bound to glycan revealed that the three variable heavy-chain complementarity-determining regions formed a cavity into which glycan could insert and neutralized multiple HIV-1 isolates with high-mannose glycans. Thus, HIV-1 Env vaccination induced mannose-dependent antibodies with characteristics of V3-glycan bnAb precursors.

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Teaser

Most bnAb epitopes on HIV-1 Envelope include host glycans, but previous Env vaccines have not induced glycan-dependent antibodies. Saunders et al. describe here the ontogeny, crystal structure with glycan, and virion Man9GlcNAc2-dependent neutralization for glycan-reactive antibodies induced by envelope vaccination.


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