Effect of IL-18 on IFNγ production. Splenocytes from WT (▨) or ICE-deficient (□) mice were incubated for 24 hours with 10 μg/mL of zymosan in the presence of increasing concentrations of IL-18 and levels of IFNγ were measured. Data are the mean ± SEM of 5 mice per group. The unpaired Student's t-test was used for comparison between WT and ICE-deficient mice, whereas for comparisons within a group, ANOVA for repeated measures was used.