Activation of Lyt-2+ T cells by antibodies towards brain-associated antigens. II. Antibody-dependent induction of "nonspecific" cell-mediated cytotoxicity.
Purified IgG from a rabbit anti-mouse brain antiserum (RaMB), previously shown to activate most Lyt-2+ T cells, was probed for lectin-like effects on cell-mediated cytolysis (CML) and found to induce "nonspecific" killing of syngeneic B cell targets by allospecific cytotoxic T lymphocytes (CTL) as effectively as concanavalin A, and at levels comparable to antigen-specific cytolysis of target cells. Interestingly, RaMB-mediated "nonspecific" CML of syngeneic targets, by polyclonally or specifically activated CTL, was restricted to B cell targets and cold target inhibition experiments indicated that syngeneic target cell blasts do not functionally interact with effector CTL in the presence of RaMB. The role of target cell Fc receptors was demonstrated by the competitive inhibition of RaMB-dependent CML by normal rabbit IgG. We conclude that RaMB both activates and bridges the effector CTL to target cells, RaMB-mediated "nonspecific" CML being a similar phenomenon to lectin-facilitated "nonspecific" cytolysis, and the mirror image of classical ADCC. These observations allowed us to interpret the effects of RaMB on allo-major histocompatibility complex-specific CML. Since RaMB stimulates specific CML of B cell targets while selectively blocking that of T cell targets, we conclude that RaMB antibodies interact with structures associated with the CTL antigen receptor, explaining the contradictory effects previously reported with monoclonal antibodies against the CTL receptor complex, which can both stimulate and inhibit T cell functions.
D000818:Animals; D000906:Antibodies / Q000276:immunology; D000950:Antigens, Ly / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D001921:Brain / Q000276:immunology*; D002478:Cells, Cultured; D002642:Chick Embryo; D003429:Cross Reactions; D003602:Cytotoxicity, Immunologic; D007519:Isoantigens / Q000276:immunology; D051379:Mice; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
D000906:Antibodies; D000950:Antigens, Ly; D007519:Isoantigens; D011948:Receptors, Antigen, T-Cell