Whereas the increased susceptibility in caspase-1/11-/- mice was clearly associated with reduced expression of protective IFN-γ [13,22], we found caspase-6-/- mice even to exhibit increased mRNA expression levels of IFN-γ at 24 hours after infection when the bacterial load was approx. 100-fold higher in the knockout animals compared to the WT animals. Here, CASP1 is linked to infection.