title: Anti-idiotype antibodies to the 9.1C3 blocking antibody used to probe the lethal hit stage of NK cell-mediated cytolysis.
abstract: We previously described a monoclonal antibody, 9.1C3, which blocked natural killer (NK) cell-mediated cytolysis by acting on effector cells during a late step in the lethal hit stage. The present work describes the production in rabbits of anti-idiotypic (anti-id) antibodies to the 9.1C3 antibody. In addition to reacting specifically with the 9.1C3 antibody, the anti-id antibodies bound strongly to the K562 target cell. The anti-id antibodies blocked killing of K562 targets by NK, antibody-dependent cellular cytotoxicity, and NK-like cells but did not inhibit killing by cytotoxic T lymphocytes (CTL). Pretreatment of cells and washing before assay indicated that blocking occurred at the target cell level. Of particular interest, single cell assays with Percoll-enriched large granular lymphocytes demonstrated that the antibodies caused no reduction in binding. These data are consistent with a model for NK cell-mediated lysis that involves a secondary target cell receptor independent of the primary NK-target cell interaction. The anti-id antibodies immunoprecipitated cell surface proteins of relative m.w. 79K and 62K unreduced, and 94K and 79K reduced from K562 target cells. The development of anti-id antibodies may be a useful procedure to explore the structure and function of cellular receptors involved in NK cell-mediated cytolysis.
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology / Q000302:isolation & purification / Q000502:physiology*; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000502:physiology; D000937:Antigen-Antibody Reactions; D000954:Antigens, Surface / Q000302:isolation & purification; D000961:Antilymphocyte Serum / Q000494:pharmacology; D001666:Binding Sites, Antibody; D001667:Binding, Competitive; D011232:Chemical Precipitation; D003602:Cytotoxicity, Immunologic; D006801:Humans; D007111:Immunity, Cellular; D007130:Immunoglobulin Idiotypes / Q000276:immunology*; D007694:Killer Cells, Natural / Q000276:immunology*; D011817:Rabbits
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D000961:Antilymphocyte Serum; D007130:Immunoglobulin Idiotypes