IL18 and viral infectious disease: As shown in Fig. 8, when the expression of caspase-1 was inhibited by caspase-1 siRNA (Figs 8a–c and 9a–c), the infection of CVB3 or EV71 failed to elicit the elevated maturation of both IL-1β and IL-18 (Figs 8a,d,e and 9a,d,e), indicating that the maturation of both cytokines depends on caspase-1 during viral infection.