Fig. 1.

TNF affects IL-15-induced STAT3 activation. (A) RBE4 cells transfected with a STAT3 luciferase reporter were treated with IL-15 (100 ng/ml; light bars) in the presence and absence of TNF as indicated (dark bars). Co-treatment significantly increased and pretreatment with TNF for 12 h doubled IL-15-induced reporter activity (*p < 0.05, ***p < 0.005). The graph is representative of three independent experiments, n=3/data point. (B) hCMEC/D3 cells were treated with IL-15 (100ng/ml) for the indicated times and extracts were exposed to western blot analysis. Endogenous STAT3 was not phosphorylated. Similar results were obtained with RBE4 cells. Results shown are representative of each of two independent experiments with hCMEC/D3 and RBE4 cells.