Donius, Luke R.Cheng, YuxingChoi, JaewonSun, Zhen-YuHanson, MelissaZhang, MichaelGierahn, Todd M.Marquez, SusannaUduman, MohammedKleinstein, Steven H.Irvine, DarrellLove, J. ChristopherReinherz, Ellis L.Kim, Mikyung2016-11-182016Donius, L. R., Y. Cheng, J. Choi, Z. J. Sun, M. Hanson, M. Zhang, T. M. Gierahn, et al. 2016. “Generation of Long-Lived Bone Marrow Plasma Cells Secreting Antibodies Specific for the HIV-1 gp41 Membrane-Proximal External Region in the Absence of Polyreactivity.” Journal of Virology 90 (19): 8875-8890. doi:10.1128/JVI.01089-16. http://dx.doi.org/10.1128/JVI.01089-16.0022-538Xhttp://nrs.harvard.edu/urn-3:HUL.InstRepos:29407679ABSTRACT An effective preventive vaccine is highly sought after in order to stem the current HIV-1 pandemic. Both conservation of contiguous gp41 membrane-proximal external region (MPER) amino acid sequences across HIV-1 clades and the ability of anti-MPER broadly neutralizing antibodies (BNAbs) to block viral hemifusion/fusion establish the MPER as a prime vaccination target. In earlier studies, we described the development of an MPER vaccine formulation that takes advantage of liposomes to array the MPER on a lipid bilayer surface, paralleling its native configuration on the virus membrane while also incorporating molecular adjuvant and CD4 T cell epitope cargo. Here we demonstrate that several immunizations with MPER/liposomes induce high levels of bone marrow long-lived plasma cell (LLPC) antibody production. Single-cell immunoglobulin gene retrieval analysis shows that these plasma cells are derived from a germ line repertoire of B cells with a diverse representation of immunoglobulin genes, exhibiting antigen-driven positive selection. Characterization of LLPC recombinant monoclonal antibodies (rMAbs) indicates that antigen recognition is achieved through convergence on a common epitopic focus by utilizing various complementarity-determining region H3 (CDRH3) lengths. Importantly, the vast majority of rMAbs produced from these cells lack polyreactivity yet manifest antigen specificity in the context of lipids, shaping MPER-specific paratopes through selective pressure. Taken together, these findings demonstrate that the MPER is a vaccine target with minimal risk of generating off-target autoimmunity. IMPORTANCE: A useful vaccine must generate desired long-term, antigen-specific antibody responses devoid of polyreactivity or autoreactivity. The common polyreactive features of some HIV-1 BNAbs have raised concern about elicitation of anti-MPER antibodies. Utilizing single-LLPC repertoire analysis and biophysical characterization of anti-MPER rMAbs, we show that their fine specificities require a structural fitness of the antibody combining site involving heavy and light chain variable domains shaped by somatic hypermutation and affinity maturation of B cells in the germinal center. Perhaps more importantly, our results demonstrate that the majority of MPER-specific antibodies are not inherently polyspecific and/or autoreactive, suggesting that polyreactivity of MPER-specific antibodies is separable from their antigen specificity.en-USJournal Article2016-11-1810.1128/JVI.01089-16