Structural comparison of I-A antigens produced by a cloned murine T suppressor cell line with B-cell-derived I-A.
A cloned, antigen-specific T suppressor cell line derived from a CBA mouse expresses large amounts of I-A and I-E antigens. Comparative two-dimensional polyacrylamid gel electrophoresis of biosynthetically labeled I-A antigens immunoprecipitated with a variety of monoclonal I-Ak-specific antibodies suggested that alpha, beta and Ii polypeptide chains are identical with B-cell-derived I-A. Dimeric complexes formed by I-A chains derived from B or T suppressor cells were also similar with two major exceptions. Pulse-labeled T-cell-derived Ia antigen was complexed with two additional unknown components of about 31K. These components were not visible in pulse-chased (processed) materials. In addition, T suppressor-cell-derived I-A antigens did not contain S-S linked dimers consisting of processed alpha and beta chains, which are usually formed during solubilization of B cells. We consider the possibility that in T cells these chains are associated with other structures, thus preventing S-S linkage between alpha and beta chains.
D000818:Animals; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology; D002460:Cell Line; D004220:Disulfides; D006023:Glycoproteins / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000032:analysis*; D046911:Macromolecular Substances; D051379:Mice; D008970:Molecular Weight; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D004220:Disulfides; D006023:Glycoproteins; D000949:Histocompatibility Antigens Class II; D046911:Macromolecular Substances