TCR-stimulated cytokine synthesis of IL-10 requires p38 in HSV-infected T cells. Fibroblast monolayers were infected with HSV as before. Human PBMC were preincubated with 10 μM SB203580, a p38-specific inhibitor, or with the control carrier. PBMC were added to fibroblasts, and SB203580 was maintained throughout the assay. Supernatants were removed, and TNF-α and IL-10 were detected using an ELISA. Data represent the mean cytokine levels from four independent experiments. *, P < 0.05, Student's t test.