Fig. 2.

Phosphorylation and inhibition of p38 MAPK. (A and B) Western blot analysis by antiphospho-p38 Ab. Cell extracts were prepared after stimulation with IL-1β (10 ng/ml) and IL-18 (50 ng/ml) for indicated times by trypsinization (A). Direct lysis in Triton buffer was used to prepare cell lysates (B). (C) A549-Rβ cells were preincubated for 1 h with increasing concentrations (0.5–2 μM) of the p38 inhibitor, SB203580, and stimulated with IL-1β or IL-18 at the same concentration in A and B. After 24 h, the supernatants were removed and assayed for IL-8 concentration by enhanced chemiluminescence. Data represent the mean ± SEM (n = 3).