Differential effects of N-acetyl-L-cysteine on IL-2-vs IL-12-driven proliferation of a T cell clone: Implications for distinct signalling pathways

Using a T cell clone (2D6) capable of responding to IL-2 and IL-12, we compared the effects of NAC on IL-2 and IL-12-driven T cell proliferation. Addition of N-acetylcysteine (NAC) to 2D6 cultures did not affect IL-2 stimulated proliferation, but strikingly inhibited IL-12 stimulated proliferation. These differential NAC effects did not correlate with the patterns of the mitogen-activated protein kinase (MAPK) activation following cytokine stimulation and its regulation by NAC, Although a p38 MAPK inhibitor downregulated both IL-2- and IL-12-induced proliferation, this effect was seen at drug concentrations one order higher than those reportedly used to specifically inhibit p38 MAPK. The results suggest the existence of distinct signalling pathways and a common, indispensable signalling molecule in IL-2- and IL-12 driven T cell proliferation. (C) 2000 Academic Press.