In previous studies, IL-4 has been reported to interfere with IL-2-driven generation of lymphokine-activated killer (LAK) activity. In this investigation, we have demonstrated that IL-4 inhibited the IL-2-induced differentiation of large granular lymphocytes (LGL) into LAK effectors by a mechanism involving, at least in part, an increase in LGL intracellular cAMP levels. In contrast, with its capacity to induce cAMP accumulation in resting LGL, IL-4 had a very negligible effect on LAK activity induction, and cAMP levels increase in LGL that had been preincubated with IL-2. Furthermore, the inhibitory effect of IL-4 on LAK activity generation also correlated with a marked decrease in N-CBZ-L-lysine thiobenzylester esterase activity, with an inhibition of tumor necrosis factor (TNF) mRNA expression and TNF production by IL-2-stimulated LGL. These results strongly suggest that complex signaling processes could be ascribed to the dual activities of cytokines and their interplay in LAK promotion.
J Y Blay, D Branellec, E Robinet, B Dugas, F Gay, S Chouaïb
The Editorial Board will only consider comments that are deemed relevant and of interest to readers. The Journal will not post data that have not been subjected to peer review; or a comment that is essentially a reiteration of another comment.