Characterization of T cells bearing HLA-DR antigens in rheumatoid arthritis.
It has been demonstrated that T cells bearing HLA-DR antigens on their surface are actively involved in an immune response. In diseases of disordered immunoregulation, including rheumatoid arthritis (RA), there are elevated numbers of circulating HLA-DR+ T cells. In this study, we examined the cellular physiology of these T cells in RA patients. Using tritiated thymidine incorporation, we found that, in most patients, HLA-DR+ cells do not account for a significant amount of spontaneous proliferation found in peripheral blood T cells. RNA hybridization studies, using a cloned HLA-DR alpha chain gene probe, indicate that the T cells actively synthesize HLA-DR antigens rather than passively adsorbing them. The cell surface phenotype of the HLA-DR+ T cells was analyzed using double immunofluorescence and a variety of monoclonal antibodies. The expression of T cell differentiation antigens T4, T6, T8, and T10 varied markedly from patient to patient. In some patients, a significant number of cells expressed both T4 and T8 antigens. Most HLA-DR+ cells also express antigens defined by the following antibodies: anti-Tac (the interleukin-2 receptor), J2 (a glycoprotein found on T cell blasts), and ILR-1 (a class II major histocompatibility complex antigen). Activated T cells bearing HLA-DR antigens may play a role in the development of RA. Our data demonstrate that although these cells are not lymphoblasts, they possess a distinct cell surface phenotype.
D000954:Antigens, Surface / Q000032:analysis; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000235:genetics / Q000276:immunology*; D005802:Genes, MHC Class II; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II / Q000032:analysis* / Q000235:genetics; D006801:Humans; D008213:Lymphocyte Activation; D010641:Phenotype; D012333:RNA, Messenger / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology* / Q000378:metabolism
D000954:Antigens, Surface; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D012333:RNA, Messenger