FIG. 8.

Pneumolysin-induced IL-1β and IL-18 production is caspase-1 dependent. Peritoneal macrophages were stimulated with cholesterol-treated rPLY (1 μg/ml) in the presence or absence of a broad-spectrum caspase inhibitor (z-VAD-fmk [30 μM]) and a caspase-1-specific inhibitor (z-YVAD-cmk [30 μM]) for 24 h, and the culture supernatant was collected. The amounts of IL-1β (A), IL-18 (B), IL-6 (C), and IL-12p40 (D) were determined by ELISA. The results are representative of three separate experiments. The data are the means ± standard deviations for three or four determinations. *, P < 0.05 compared to no-inhibitor treatment.