FIG. 4.

Specific inhibitory effects of MAPK inhibitors. C57BL/6 peritoneal macrophages (3 × 10⁶ cells) were pretreated with U0126, PD98059, or SB203580 (1 to 50 μM) for 2 h and then stimulated with rHagB (20 μg/ml) for 30 min. Equal amounts of whole-cell lysates were subjected to electrophoresis on a 10% Tris-HCl gel, and Western blots were done using a specific Ab against the phosphorylated form of p38 (Thr180/Tyr182) or ERK (p44/42; Thr202/Tyr204). The levels of total p38 in the samples were determined by stripping the blots and reprobing with a specific anti-p38 Ab. Blots are representative of results obtained in three separate experiments.