title: A human Ia cytoplasmic determinant located on multiple forms of invariant chain (gamma, gamma 2, gamma 3).
abstract: An antigenic determinant present in the cytoplasm, but not on the surface membrane of human Ia+ cells, is defined by a monoclonal antibody (VIC-Y1) and is shown by immunoprecipitation and by NEPHGE to be expressed by Ia oligomers. Immunoprecipitations of cellfree translates and of purified Ia subunits indicate that the VIC-Y1 determinant is located on the Ia gamma-(invariant) chain, as well as on two other related molecules, provisionally termed gamma 2 and gamma 3. Within our experimental conditions, the three forms of gamma-chains co-precipitate exclusively with Ia oligomers. As detected by VIC-Y1 and in the limits of our assays, gamma-chains could not be found at the cell surface; their tissue distribution, determined by cytoplasmic indirect immunofluorescence with VIC-Y1, closely resembles that of Ia antigens, with the possible exception of acute lymphatic leukemia cells (Ia+, gamma-chain-).
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology; D003593:Cytoplasm / Q000276:immunology*; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000235:genetics / Q000276:immunology*; D005455:Fluorescent Antibody Technique; D005802:Genes, MHC Class II; D000949:Histocompatibility Antigens Class II / Q000032:analysis / Q000276:immunology* / Q000302:isolation & purification; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D011110:Polymorphism, Genetic; D011817:Rabbits
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D000949:Histocompatibility Antigens Class II