Inhibition of adenylate cyclase by IL 2 in human T lymphocytes is mediated by protein kinase C

Abstract Interleukin 2 (IL 2) inhibited basal as well as PGE 2 , isoproterenol and forskolin stimulated cAMP production in human T lymphocytes. Although the stimulation of adenylate cyclase by activators of the enzyme was evident in lymphocyte membrane preparations, the inhibitory effect of IL 2 was observed only if cells were pretreated with IL 2 and the membranes activated with Ca ++ and ATP. Additionally, when purified protein kinase C was reconstituted into untreated membranes and activated with Ca ++ and ATP, both receptor and non-receptor stimulated adenylate cyclase was inhibited. These results suggest that the inhibition of adenylate cyclase in human T lymphocytes by IL 2 is mediated by protein kinase C.