title: Virolysis and in vitro neutralization of HIV-1 by humanized monoclonal antibody hNM-01.
abstract: Antibody humanization by transplanting the complimentarity determining region (CDR) to a human framework aims to reduce the response of the human immune system against a foreign molecule during passive immunization. We transferred the CDR from the murine monoclonal antibody (MAb) NM-01 to a human IgG frame. The humanized NM-01 (hNM-01) recognizes the same epitope on Human Immunodeficiency Virus type 1 (HIV-1) envelope as its murine progenitor, but with greater efficiency, and shows enhanced neutralization of HIV-1. We have shown that this increase in reactivity may be attributed to residue 4 of the humanized kappa chain, where the presence of a methionine residue rather than the murine leucine appears to promote a more advantageous conformation of the antigen-binding site, perhaps via packing interactions with the V(kappa) CDR1. The capacity of humanized NM-01 to neutralize direct clinical isolates was also examined with the expectation that hNM-01 will prove suitable for development as a therapeutic agent. This reshaped antibody reacted with several clinical isolates of HIV-1 tested. Moreover, we proved the ability of this antibody of its activation of complement by flow cytometry and electron microscopy analysis. Although hNM-01 alone was capable of neutralizing HIV-1, the presence of complement enhanced neutralization. The enhancement of complement activation was also observed in hNM-01 than murine progenitor. This finding supports a potential role for antibody-dependent complement-mediated virolysis and more effective neutralization in HIV-1 therapy.
authors.affiliation: Department of Microbiology, Jikei University School of Medicine, Tokyo, Japan. nakamura@jikei.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Nakamura
authors.forename: M
authors.initials: M
authors.lastname: Terada
authors.forename: H
authors.initials: H
authors.lastname: Sasaki
authors.forename: M
authors.initials: M
authors.lastname: Kamada
authors.forename: T
authors.initials: T
authors.lastname: Ohno
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019380:Anti-HIV Agents / Q000737:chemistry / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D000914:Antibodies, Viral / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D000915:Antibody Affinity; D003167:Complement Activation; D022801:Complementarity Determining Regions; D015497:HIV-1 / Q000187:drug effects / Q000276:immunology*; D006801:Humans; D006825:Hybridomas; D007074:Immunoglobulin G; D051379:Mice; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology
chemical_list: D019380:Anti-HIV Agents; D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D022801:Complementarity Determining Regions; D007074:Immunoglobulin G; D011993:Recombinant Fusion Proteins