title: Serological and cellular definition of a new HLA-DR associated determinant, MC1, and its association with rheumatoid arthritis.
abstract: A new serological HLA-DR associated determinant was defined by a cluster of six B cell alloantisera. This determinant, designated as MC1, was strongly associated with DR1 and DR4 and appeared unrelated to MB, MT, and SB. The antigen frequency of MC1 was 47% in Caucasoids and 43% in Blacks. Mixed leukocyte culture cloning yielded an alloreactive T cell clone with PLT specificity associated with MC1. We have also observed that certain alloreactive clones may also acquire expression of MC1 but not DR4 during long-term culture maintenance in the presence of DR4, MC1-positive feeder cells. Disease association studies showed a significantly increased frequency of MC1 in adult rheumatoid arthritis patients (93.5% vs 47.4% in normals; relative risk 16.1). These findings suggest that MC1 represents a novel HLA-D encoded determinant.
mesh_terms: D000483:Alleles; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D000939:Epitopes / Q000032:analysis*; D005787:Gene Frequency; D005802:Genes, MHC Class II; D006684:HLA-DR Antigens; D015798:HLA-DR1 Antigen; D015804:HLA-DR4 Antigen; D000949:Histocompatibility Antigens Class II / Q000032:analysis*; D006801:Humans; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000939:Epitopes; D006684:HLA-DR Antigens; D015798:HLA-DR1 Antigen; D015804:HLA-DR4 Antigen; D000949:Histocompatibility Antigens Class II