title: Human IgG1 antibodies antagonizing activating receptor NKG2D on natural killer cells.
abstract: NKG2D is a surface receptor expressed on NK cells but also on CD8(+) T cells, gammadelta T cells, and auto-reactive CD4(+)/CD28(-) T cells of patients with rheumatoid arthritis. Various studies suggested that NKG2D plays a critical role in autoimmune diseases, e.g., in diabetes, celiac disease and rheumatoid arthritis (RA), rendering the activating receptor a potential target for antibody-based therapies. Here, we describe the generation and characteristics of a panel of human, high-affinity anti-NKG2D IgG1 monoclonal antibodies (mAbs) derived by phage display. The lead molecule mAb E4 bound with an affinity (KD) of 2.7 +/- 1.4 x 10(-11) M to soluble and membrane-bound human NKG2D, and cross-reacted with NKG2D from cynomolgus macaque, indicating potential suitability for studies in a relevant primate model. MAb E4 potently antagonized the cytolytic activity of NKL cells against BaF/3-MICA cells expressing NKG2D ligand, and blocked the NKG2D ligand-induced secretion of TNFalpha, IFNgamma and GM-CSF, as well as surface expression of CRTAM by NK cells cultured on immobilized MICA or ULBP-1 ligands. The antibody did not show a detectable loss of binding to NKG2D after seven days in human serum at 37 degrees C, and resisted thermal inactivation up to 70 degrees C. Based on these results, anti-human NKG2D mAb E4 provides an ideal candidate for development of a novel therapeutic agent antagonizing a key receptor of NK and cytotoxic T cells with implications in autoimmune diseases.
authors.affiliation: Micromet AG, Munich, Germany.
authors.forename: Jutta
authors.initials: J
authors.lastname: Steigerwald
authors.forename: Tobias
authors.initials: T
authors.lastname: Raum
authors.forename: Stefan
authors.initials: S
authors.lastname: Pflanz
authors.forename: Ronny
authors.initials: R
authors.lastname: Cierpka
authors.forename: Susanne
authors.initials: S
authors.lastname: Mangold
authors.forename: Doris
authors.initials: D
authors.lastname: Rau
authors.forename: Patrick
authors.initials: P
authors.lastname: Hoffmann
authors.forename: Majk
authors.initials: M
authors.lastname: Kvesic
authors.forename: Christina
authors.initials: C
authors.lastname: Zube
authors.forename: Stefanie
authors.initials: S
authors.lastname: Linnerbauer
authors.forename: John
authors.initials: J
authors.lastname: Lumsden
authors.forename: Mirnaalini
authors.initials: M
authors.lastname: Sriskandarajah
authors.forename: Peter
authors.initials: P
authors.lastname: Kufer
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Baeuerle
authors.forename: Jörg
authors.initials: J
authors.lastname: Volkland
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000915:Antibody Affinity; D002478:Cells, Cultured; D004195:Disease Models, Animal; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D007136:Immunoglobulins / Q000378:metabolism; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism; D008252:Macaca fascicularis; D051379:Mice; D055655:NK Cell Lectin-Like Receptor Subfamily K / Q000276:immunology* / Q000378:metabolism; D019151:Peptide Library; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D007074:Immunoglobulin G; D007136:Immunoglobulins; D055655:NK Cell Lectin-Like Receptor Subfamily K; D019151:Peptide Library; C408522:class-I restricted T cell-associated molecule