Figure 3.

The role for caspase-1 in enterohaemorrhagic Escherichia coli (EHEC) O157:H7 enterohaemolysin-induced interleukin-1β (IL-1β) production. Differentiated human THP-1 cells and mouse peritoneal macrophages (PMs) were infected with EDL933, ΔehxA or ΔehxA/pehxA for 4 hr. (a) Lysates from the cells were analysed by immunoblotting directed against active caspase-1 p10. (b) The THP-1 cells were treated with 10 μm of the caspase-1 inhibitor Z-YVAD-FMK for 1 hr before infection with EHEC O157:H7. The IL-1β concentration in the supernatant was determined at 4 hr post-infection by ELISA. (b) The results represent the mean ± SD of three independent experiments. Significant differences (**P < 0·01) are indicated. n.s., not significant (P > 0·05).