title: Peripheral Membrane Interactions Boost the Engagement by an Anti-HIV-1 Broadly Neutralizing Antibody.
abstract: The 4E10 antibody displays an extreme breadth of HIV-1 neutralization and therefore constitutes a suitable model system for structure-guided vaccine design and immunotherapeutics against AIDS. In this regard, the relevance of autoreactivity with membrane lipids for the biological function of this antibody is still a subject of controversy. To address this dispute, herein we have compared the membrane partitioning ability of the 4E10 antibody and several of its variants, which were mutated at the region of the paratope surface in contact with the membrane interface. We first employed a physical separation approach (vesicle flotation) and subsequently carried out quantitative fluorescence measurements in an intact system (spectroscopic titration), using 4E10 Fab labeled with a polarity-sensitive fluorescent probe. Moreover, recognition of epitope peptide in membrane was demonstrated by photo-cross-linking assays using a Fab that incorporated the genetically encoded unnatural amino acidp-benzoylphenylalanine. The experimental data ruled out that the proposed stereospecific recognition of viral lipids was necessary for the function of the antibody. In contrast, our data suggest that nonspecific electrostatic interactions between basic residues of 4E10 and acidic phospholipids in the membranes contribute to the observed biological function. Moreover, the energetics of membrane partitioning indicated that 4E10 behaves as a peripheral membrane protein, tightening the binding to the ligand epitope inserted in the viral membrane. The implications of these findings for the natural production and biological function of this antibody are discussed.
authors.affiliation: From the Biofisika Institute (Consejo Superior de Investigaciones Científicas, UPV/EHU), and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain and.|the Department of Bioengineering, Graduate School of Engineering, University of Tokyo, Tokyo, 113-8656, Japan.
authors.forename: Edurne
authors.initials: E
authors.lastname: Rujas
authors.affiliation: the Department of Bioengineering, Graduate School of Engineering, University of Tokyo, Tokyo, 113-8656, Japan.
authors.forename: José M M
authors.identifier: http://orcid.org/0000-0001-5568-2369
authors.initials: JM
authors.lastname: Caaveiro
authors.affiliation: From the Biofisika Institute (Consejo Superior de Investigaciones Científicas, UPV/EHU), and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain and.
authors.forename: Sara
authors.initials: S
authors.lastname: Insausti
authors.affiliation: From the Biofisika Institute (Consejo Superior de Investigaciones Científicas, UPV/EHU), and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain and.
authors.forename: Miguel
authors.initials: M
authors.lastname: García-Porras
authors.affiliation: the Department of Bioengineering, Graduate School of Engineering, University of Tokyo, Tokyo, 113-8656, Japan tsumoto@k.u-tokyo.ac.jp.
authors.forename: Kouhei
authors.initials: K
authors.lastname: Tsumoto
authors.affiliation: From the Biofisika Institute (Consejo Superior de Investigaciones Científicas, UPV/EHU), and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain and gbpniesj@lg.ehu.es.
authors.forename: José L
authors.initials: JL
authors.lastname: Nieva
mesh_terms: D016915:AIDS Vaccines; D000911:Antibodies, Monoclonal / Q000009:adverse effects / Q000276:immunology*; D057134:Antibodies, Neutralizing / Q000009:adverse effects / Q000276:immunology*; D015551:Autoimmunity; D000080908:Broadly Neutralizing Antibodies; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology*; D015195:Drug Design; D000939:Epitopes; D015483:HIV Antibodies / Q000009:adverse effects / Q000276:immunology*; D006801:Humans; D008563:Membrane Lipids / Q000276:immunology; D014763:Viral Matrix Proteins / Q000276:immunology
chemical_list: C558559:4E10 monoclonal antibody; D016915:AIDS Vaccines; D000911:Antibodies, Monoclonal; D057134:Antibodies, Neutralizing; D000080908:Broadly Neutralizing Antibodies; D000939:Epitopes; D015483:HIV Antibodies; D008563:Membrane Lipids; D014763:Viral Matrix Proteins
keywords: 4E10 antibody; MPER vaccine; antibody; broadly neutralizing antibody; human immunodeficiency virus (HIV); lipid polyreactivity; membrane protein; protein-lipid interaction; protein-membrane interaction; vaccine development