title: Monoclonal antibodies against the NK cell-FcR and the T3-complex potentiate normal lymphocyte killing.
abstract: Pretreatment of normal human lymphocytes with monoclonal IgG against the NK cell-FcR (IgG) or the T3 complex was found to potentiate killing of most NK sensitive target cells with the exception of T-cell derived cells. Anti-FcR IgM monoclonals were suppressive for all target cells. IgG anti-FcR mediated potentiation required minute amounts of antibody but was also seen at high anti-FcR concentrations that modulated FcR activity. Potentiated and FcR modulated cells retained anti-FcR IgG on the membrane and conjugated normally to target cells. Anti-FcR potentiation blocked antibody-dependent killing but did not influence lectin-dependent killing, with anti-T3 the opposed effect was seen. Combined anti-FcR and anti-T3 treatment resulted in decreased potentiation. The results suggest that the NK cell-FcR may be activated during normal NK cell killing (without the addition of antibody) as suggested for FcR in B cell triggering.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D000920:Antibody-Dependent Cell Cytotoxicity; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000276:immunology*; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic; D006801:Humans; D007111:Immunity, Cellular; D066298:In Vitro Techniques; D007694:Killer Cells, Natural / Q000276:immunology*; D037102:Lectins / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D011961:Receptors, Fc / Q000276:immunology*; D017452:Receptors, IgG; D012397:Rosette Formation; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D037102:Lectins; D011948:Receptors, Antigen, T-Cell; D011961:Receptors, Fc; D017452:Receptors, IgG