We did not observe a significant difference in the amount of the neutrophil marker myeloperoxidase (MPO) in the feces of Nlrc4–/–Il1r1–/– versus Nlrc4–/– Il1r1+/– mice at 1 day post-infection, however, there was a modest but significant decrease in fecal MPO in Nlrc4–/–Il1r1–/– relative to Nlrc4–/– Il1r1+/– mice at 2 days post-infection, suggesting that IL-1 might be essential for sustained neutrophilic inflammation during Shigella infection (Figure 6F). This evidence concerns the gene NLRC4 and infection.