Treatment with the caspase-1 inhibitor YVAD-CHO in combination with PGE2 abolished release of IL-1β upon infection with both Y. enterocolitica and S. Typhimurium (Figure 6B and Supplementary Figure S4B), supporting the fact that caspase-1 is responsible for the PGE2-triggered stimulation of inflammasome. The gene discussed is IL1B; the disease is infection.