title: Evidence for polymorphism of MB3 antigens among three HLA-D clusters associated with HLA-DR4.
abstract: In a previous study, we showed that the three hitherto serologically indistinguishable HLA-D specificities associated with HLA-DR4, HLA- DYT , HLA- DKT2 , and HLA-Dw4 can be distinguished on the basis of their reactivity with two distinct Ia-like-specific monoclonal antibodies, HU-18 and HU-23. In this study, we attempted to identify and characterize Ia-like molecules recognized by HU-18 and HU-23 on a molecular level because Ia subsets (HLA-DR, MB, MT, or SB) identified by them remained unknown. The results of sequential coprecipitation assays and two-dimensional gel analyses showed that both HU-18 and HU-23 recognize antigenic determinants borne on MB3 but not on HLA-DRw6.2 molecules. Because the two monoclonal antibodies, specific for determinants carried on MB3 molecules, show distinct reactivity against homozygous typing cells defining HLA- DYT , HLA- DKT2 , and HLA-Dw4, all of which share DR4- MB3 , the data indicate that these three HLA-D clusters associated with HLA-DR4 possess distinct MB3 molecules, suggesting the existence of polymorphism in MB3 antigens.
mesh_terms: D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology; D002460:Cell Line; D002472:Cell Transformation, Viral; D000939:Epitopes / Q000032:analysis; D005802:Genes, MHC Class II; D006684:HLA-DR Antigens; D004854:Herpesvirus 4, Human; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006801:Humans; D007106:Immune Sera; D011110:Polymorphism, Genetic
chemical_list: D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D000939:Epitopes; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D007106:Immune Sera