REGULATION OF INTERLEUKIN-2 AND INTERLEUKIN-6 PRODUCTION FROM T-CELLS - INVOLVEMENT OF INTERLEUKIN-1-BETA AND TRANSFORMING GROWTH-FACTOR-BETA

The effect of recombinant (r) interleukin-1β (rIL-1β) and transforming growth factor-β (TGF-β) on the production of interleukin-2 (IL-2) and interleukin-6 (IL-6) from an antigen-specific (LBRM-33-1A5) and an antigen-nonspecific (EL-4-NOB-1) T-cell line was investigated. rIL-1β induced the production of IL-2 and IL-6 from EL-4-NOB-1 cells in a dose-related manner. The LBRM-33-1A5 cells required phytohemagglutinin (PHA) in addition to rIL-1β in order to produce IL-2 and IL-6. IL-2 production was found to precede IL-6 production in both cell lines. No IL-2 or IL-6 production was observed by adding r murine tumor necrosis factor-α or r murine interferon γ to the cells. The presence of 1 ng/ml TGF-β reduced IL-2 and IL-6 production from both T-cell lines by more than 80%. The inhibition of IL-2 and IL-6 production was still evident by a concentration as low as 10 pg/ml of TGF-β. rIL-1β and PHA also stimulated murine thymocytes to produce IL-6 which was inhibited up to 85% in the presence of 1 ng/ml TGF-β. Taken together these results suggest that TGF-β may suppress immune responses by inhibiting the endogenous production of IL-2 and IL-6. © 1990.