Interactions of Fc receptors with antibodies against Ia antigens and other cell surface components.
Two Fc receptor-dependent tests were investigated to study the question of a relationship between Fc receptors and known cell surface antigens, in particular I region-associated (Ia) antigens: (a) a rosette assay with antibody-coated erythrocytes (EA) as indicator cells and normal mouse lymphoid cells as source of rosette-forming cells, and (b) a cytotoxicity test with antibody-coated erythrocytes as target cells and normal mouse spleen cells as a source of cytotoxic cells (K cells). EA rosettes were specifically inhibited by antibodies reacting with Ia antigens. Various other antisera reacting with antigens on B lymphocytes, like anti-Ly 4.2 (raised in H-2 identical mice), rabbit antimouse B-cell serum, or rabbit antimouse immunoglobulin, also specifically inhibited the rosettes. No inhibition occurred in the presence of allogeneic or xenogeneic antisera reacting with T lymphocytes. K-cell cytotoxicity was specifically inhibited by each of the antisera (reacting with either B cells or T cells). F(ab')2 fragments of anti-Ia antibodies could still specifically inhibit EA rosettes but they could not inhibit K-cell cytotoxicity. Similar results were obtained with F(ab')2 fragments of anti-immunoglobulin antibodies. These results indicate that the mechanism of inhibition of Fc receptors in the two tests was different. In neither of the tests could we find any evidence for a unique association between the Fc receptors and Ia antigens. The Fc receptors on K cells did not seem to be associated at all with Ia antigens.
D000818:Animals; D000888:Antibodies, Anti-Idiotypic; D000937:Antigen-Antibody Reactions; D001402:B-Lymphocytes / Q000276:immunology*; D001666:Binding Sites, Antibody; D002462:Cell Membrane / Q000276:immunology*; D002645:Chickens / Q000276:immunology; D003601:Cytotoxicity Tests, Immunologic; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D006649:Histocompatibility Antigens; D007104:Immune Adherence Reaction; D007106:Immune Sera; D007125:Immunogenetics; D007140:Immunoglobulin Fab Fragments; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D008221:Lymphoid Tissue / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008815:Mice, Inbred Strains; D011817:Rabbits / Q000276:immunology
D000888:Antibodies, Anti-Idiotypic; D006649:Histocompatibility Antigens; D007106:Immune Sera; D007140:Immunoglobulin Fab Fragments; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G