title: Functional sites on Ia molecules: a molecular dissection of A alpha immunogenicity.
abstract: Ia antigens are polymorphic cell-surface molecules that control the immune response. We have begun to localize important functional sites on one of the Ia molecules, A alpha. Herein, we focus on the A alpha k and A alpha b alleles and ask what defines "b-ness" and "k-ness" for a panel of monoclonal antibodies. Two independent experimental strategies are employed: the ability of 12 monoclonal antibodies to recognize L cell transfectants bearing chimeric and mutant A alpha chains is assessed, and the amino acid sequences of A alpha chains expressed by immunoselected B lymphoma mutants are deduced. For each antibody, we identify a stretch of polymorphic residues critical for recognition; for several, we can pinpoint a single amino acid. Certain stretches of A alpha (depending on the allele) appear strikingly immunodominant.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D003001:Cloning, Molecular; D000939:Epitopes; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000276:immunology*; D051379:Mice; D009154:Mutation; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D000949:Histocompatibility Antigens Class II