title: Mouse monoclonal antibodies against rat major histocompatibility antigens. Two Ia antigens and expression of Ia and class I antigens in rat thymus.
abstract: A rat Ia (RT-1B) antigen (called Ia-A) equivalent to the mouse I-A product has been defined with mouse monoclonal antibodies (W. R. McMaster and A. F. Williams, Eur. J. Immunol. 1979. 9: 426). To identify other Ia antigens mouse monoclonal antibodies were raised against rat spleen glycoproteins depleted of the Ia-A antigen. An IgG antibody (called MRC OX17) was obtained and used to purify a molecule which had a similar structure to the Ia-A antigen and reacted with anti-Ia alloantibodies. There was no cross-reaction between the two Ia glycoproteins in assays with mouse monoclonal antibodies, alloantibodies or rabbit antibodies. In one alloantiserum almost all the detectable anti-Ia antibodies reacted with a mixture of the two Ia glycoproteins. The MRC OX17 antibody did not bind to mouse cells, but rabbit antibodies to the pure rat glycoprotein cross-reacted and recognized determinants mapping to the mouse I-E region. In the thymus the rat Ia-E antigen was on cortical epithelial and medullary reticular cells. An IgG monoclonal antibody (MRC OX18) to isotypic determinants of rat histocompatibility RT-1A antigens was also produced and used to analyze these antigens on thymus cells. The heavily labeled thymocytes were those with characteristics of mature T lymphocytes. Cortical epithelial cells and medullary dendritic-like cells were also RT-1A positive.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000276:immunology*; D006023:Glycoproteins / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D051379:Mice; D011817:Rabbits; D051381:Rats; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D013950:Thymus Gland / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D006023:Glycoproteins; D000949:Histocompatibility Antigens Class II