CASP1 and infection: To further verify the importance of caspase-1 in the attenuation of flgM-deficient Salmonella, we performed competitive infection studies where mice were orally infected with equal numbers of WT and flgM-deficient Salmonella. The WT Salmonella outcompeted flgM-deficient Salmonella in the cecum, liver, spleen and MLN in WT mice, but not Casp1−/− mice (Fig. S6).