title: Inhibition of T cell activation with a humanized anti-beta 1 integrin chain mAb.
abstract: The murine anti-CD29 mAb K20 (Mu-K20) is known to bind to the beta 1 chain of the human integrins and to inhibit activation and proliferation of T cells, implying an important potential for in vivo immunosuppression. However, use of K20 as an immunosuppressant drug would be impaired by the immunogenicity of mouse mAbs in man. We have therefore engineered K20 into (1) a mouse/human chimeric mAb (Ch-K20) that comprises the human kappa/gamma 1C regions and the K20 V regions; and (2) a humanized mAb (Hu-K20) combining the complementarity-determining regions (CDRs) of the K20 mAb with human framework (FR) and kappa/gamma 1 C regions. Both chimeric and humanized Abs were able to reproduce a range of functional properties of the original mouse mAb K20 (Mu-K20), namely, specific binding of CD29, inhibition of T cell proliferation and elevation of second messenger phosphatidic acid (PA) induced via CD3 in a soluble form, and activation of T cell proliferation in a cross-linked form. When compared to Ch-K20, the avidity of Hu-K20 was only slightly reduced. This demonstrates the feasibility of a successful humanization performed on the sole basis of the primary amino acid sequence analysis of the original mouse antibody V regions.
authors.affiliation: Laboratoire d'ImmunoGénétique Moléculaire, LIGM, UMR 9942, CNRS, Universités Montpellier I et II, France.
authors.forename: M A
authors.initials: MA
authors.lastname: Poul
authors.forename: M
authors.initials: M
authors.lastname: Ticchioni
authors.forename: A
authors.initials: A
authors.lastname: Bernard
authors.forename: M P
authors.initials: MP
authors.lastname: Lefranc
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology*; D015703:Antigens, CD / Q000276:immunology; D001483:Base Sequence; D001667:Binding, Competitive; D003001:Cloning, Molecular; D015922:Complement C1q / Q000276:immunology; D003601:Cytotoxicity Tests, Immunologic; D015322:Gene Rearrangement, B-Lymphocyte / Q000235:genetics; D006801:Humans; D006825:Hybridomas / Q000276:immunology; D007140:Immunoglobulin Fab Fragments / Q000276:immunology; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D007145:Immunoglobulin kappa-Chains / Q000235:genetics; D019012:Integrin beta1; D016023:Integrins / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008969:Molecular Sequence Data; D010712:Phosphatidic Acids / Q000096:biosynthesis; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D007140:Immunoglobulin Fab Fragments; D007143:Immunoglobulin Heavy Chains; D007145:Immunoglobulin kappa-Chains; D019012:Integrin beta1; D016023:Integrins; D010712:Phosphatidic Acids; D011993:Recombinant Fusion Proteins; D015922:Complement C1q