IL18 and infection: Rickettsia australis activated ASC-dependent inflammasome in murine BMMs as indicated by the following evidence: 1) Secretion of IL-1β and IL-18 upon infection was completely abrogated in cells deficient in ASC and caspase-1/caspase-11-double knockout cells (Figs 4 and 5); 2) Rickettsia australis infection induced cleavage of caspase-1 in the cell lysates and supernatant (Figs 4A, 5D and 6C).