title: 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.
abstract: 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.
  
  
  
  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.
authors.affiliation: Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.
authors.forename: Luke R
authors.initials: LR
authors.lastname: Donius
authors.affiliation: Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.
authors.forename: Yuxing
authors.initials: Y
authors.lastname: Cheng
authors.affiliation: Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.
authors.forename: Jaewon
authors.initials: J
authors.lastname: Choi
authors.affiliation: Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Zhen-Yu J
authors.initials: ZY
authors.lastname: Sun
authors.affiliation: Departments of Materials Science and Engineering and Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
authors.forename: Melissa
authors.initials: M
authors.lastname: Hanson
authors.affiliation: Departments of Materials Science and Engineering and Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Koch Institute for Integrative Cancer Research at MIT, Cambridge, Massachusetts, USA.
authors.forename: Todd M
authors.initials: TM
authors.lastname: Gierahn
authors.affiliation: Department of Pathology, Yale School of Medicine, New Haven, Connecticut, USA.
authors.forename: Susanna
authors.initials: S
authors.lastname: Marquez
authors.affiliation: Department of Pathology, Yale School of Medicine, New Haven, Connecticut, USA.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Uduman
authors.affiliation: Department of Pathology, Yale School of Medicine, New Haven, Connecticut, USA Department of Immunology, Yale School of Medicine, and Interdepartmental Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut, USA.
authors.forename: Steven H
authors.initials: SH
authors.lastname: Kleinstein
authors.affiliation: Departments of Materials Science and Engineering and Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA Koch Institute for Integrative Cancer Research at MIT, Cambridge, Massachusetts, USA Howard Hughes Medical Institute, Chevy Chase, Maryland, USA.
authors.forename: Darrell
authors.initials: D
authors.lastname: Irvine
authors.affiliation: Koch Institute for Integrative Cancer Research at MIT, Cambridge, Massachusetts, USA.
authors.forename: J Christopher
authors.initials: JC
authors.lastname: Love
authors.affiliation: Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.
authors.forename: Ellis L
authors.initials: EL
authors.lastname: Reinherz
authors.affiliation: Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA Department of Dermatology, Harvard Medical School, Boston, Massachusetts, USA mikyung_kim@dfci.harvard.edu.
authors.forename: Mikyung
authors.initials: M
authors.lastname: Kim
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D018985:Epitopes, B-Lymphocyte / Q000276:immunology; D015483:HIV Antibodies / Q000276:immunology* / Q000378:metabolism*; D015488:HIV Antigens / Q000276:immunology*; D015700:HIV Envelope Protein gp41 / Q000276:immunology*; D008563:Membrane Lipids / Q000378:metabolism; D010950:Plasma Cells / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D018985:Epitopes, B-Lymphocyte; D015483:HIV Antibodies; D015488:HIV Antigens; D015700:HIV Envelope Protein gp41; D008563:Membrane Lipids; C514787:gp41 protein, Human immunodeficiency virus 1