title: Expression and function of I region determinants on immunocompetent cells. I. Selective expression of I-C region determinants on immune cells.
abstract: We have examined the cytotoxic activity of anti-Iak serum and complement on various immune functions of BALB/c (H-2d) cells. Since the cytotoxic action of this antiserum on H-2d cells defines specificity Ia.7, an I-C region product, we have looked at the selective expression of this antigen. We have mainly used the in vitro anti-Lac2 response to study the cells involved in the induction and regulation of antibody. The data presented here show that Ia.7 is present on both IgM and IgG precursor B cells and in lesser amounts on plaque-forming cells. The antiserum also recognizes with less efficiency a product on specific T suppressor cells, which is possibly coded for by the adjacent I-J subregion. Both fluorescence and functional tests indicate the absence of Ia.7 on macrophages. It is also lacking on T helper cells. When we tested the antiserum on the in vitro cytotoxic responses to alloantigens, we found that neither T effector cells nor their precursors were affected.
mesh_terms: D000818:Animals; D000906:Antibodies; D000941:Antigens; D001402:B-Lymphocytes / Q000276:immunology; D003165:Complement System Proteins; D003601:Cytotoxicity Tests, Immunologic; D000939:Epitopes; D005796:Genes; D006433:Hemocyanins / Q000276:immunology; D006649:Histocompatibility Antigens; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007148:Immunoglobulin mu-Chains; D007165:Immunosuppression Therapy; D066298:In Vitro Techniques; D007785:Lactose / Q000031:analogs & derivatives / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000906:Antibodies; D000941:Antigens; D000939:Epitopes; D006649:Histocompatibility Antigens; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007148:Immunoglobulin mu-Chains; D003165:Complement System Proteins; D006433:Hemocyanins; D007785:Lactose