Activated T cells in vivo and in vitro: divergence in expression of Tac and Ia antigens in the nonblastoid small T cells of inflammation and normal T cells activated in vitro.
Elevated numbers of non-blastoid T cells expressing either the Tac or Ia antigens were found on separate cell populations in inflammatory synovial tissues and fluids of individuals with arthritis. Those synovial T cell preparations containing Tac+ cells exhibited marked proliferation upon the addition of IL 2 without concomitant mitogen stimulation; T cell eluates containing Ia+ but not Tac+ T cells did not show significantly increased levels of blastogenesis. Paired T cell preparations from blood had only minor increases in the number of Tac+ T cells and moderate increases in the number of Ia+ cells. The blood cells did not exhibit significant proliferation to IL 2. In contrast mitogen or allogeneic activation of T cells induced blastoid cells that expressed abundant per cell amount of Ia or Tac antigens. These blastoid cells resembled the small T cells of inflammation in having only very limited overlap between the population that bore Ia antigens and those with the Tac antigen; however, there was a preponderance of Tac-bearing cells.
D000954:Antigens, Surface / Q000032:analysis*; D001172:Arthritis, Rheumatoid / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000032:analysis*; D006801:Humans; D007376:Interleukin-2 / Q000502:physiology; D007958:Leukocyte Count; D008213:Lymphocyte Activation; D013167:Spondylitis, Ankylosing / Q000276:immunology; D013583:Synovial Membrane / Q000276:immunology / Q000473:pathology*; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology* / Q000473:pathology; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
D000954:Antigens, Surface; D000949:Histocompatibility Antigens Class II; D007376:Interleukin-2; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7