NAIP and shigellosis: Thus, to test directly if the mouse NAIP–NLRC4 inflammasome mediates resistance to shigellosis, we orally infected streptomycin-pretreated B6 WT and ∆Naip mice with 5 × 107 CFU of Shigella. ∆Naip mice (also called Naip1-6∆/∆ mice Rauch et al., 2016) harbor a large chromosomal deletion that eliminates expression of all mouse Naip genes.