Inhibitor of interleukin-2 in rheumatoid synovial fluid.
Although large numbers of T cells infiltrate the synovium of patients with rheumatoid arthritis (RA), the responses of these cells, as present in the blood and synovial fluid (SF), to exogenous interleukin-2 (IL-2) and their production of IL-2 are diminished. To investigate this functional defect, RA SF were examined for the presence of inhibitors of IL-1 and IL-2. A factor was found which inhibited the IL-2-induced proliferation of mitogen-stimulated human T cells and the IL-1-induced proliferation of C3H/Hej mouse thymocytes, but not IL-1-induced fibroblast proliferation. On AcA 54 Ultrogel filtration, the inhibitory activity resided in a fraction with an apparent molecular weight of greater than 70 kd and a major pI of 6.8. The inhibitory effect of RA SF on lymphocyte proliferation was partially corrected with IL-2, but not with IL-1. In the presence of RA SF, normal lymphocytes showed not only a decreased response to exogenous IL-2, but also a decreased production of IL-2. The presence of an inhibitor of IL-2 in RA SF could contribute to the IL-2-related T cell defects observed in RA.
D000818:Animals; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D005347:Fibroblasts / Q000276:immunology; D006801:Humans; D007375:Interleukin-1 / Q000032:analysis; D007376:Interleukin-2 / Q000032:analysis / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D007719:Knee Joint; D008214:Lymphocytes / Q000378:metabolism; D008222:Lymphokines / Q000032:analysis*; D051379:Mice; D008809:Mice, Inbred C3H; D013582:Synovial Fluid / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology
D007375:Interleukin-1; D007376:Interleukin-2; D008222:Lymphokines; C046147:interleukin 2 inhibitor