Figure 5.

Caspase-1 is activated during infection of macrophages infected with Salmonella. (A and B) LPS-activated murine peritoneal macrophages were infected with S. typhimurium C5. After 10 min (lane 2), 25 min (lane 3), 40 min (lane 4), and 70 min (lane 5) of infection, cell lysates were resolved on an 15% SDS/PAGE gel and immunoblotted with either an anti-caspase-1 antibody (A) or an anti-IL-1β antibody (B). As a control, macrophages were infected with the sipB mutant ST100 for 70 min (lane 1 in each gel) and processed in parallel. Both caspase-1 and its specific substrate IL-1β undergo catalytic maturation within 10 min of infection with mature forms accumulating throughout the course of infection observed.