To test this hypothesis, we infected Il22−/− mice with S. Typhimurium, and then injected them intraperitoneally with PBS or 2 μg of recombinant IL-18 at 6 h p.i. While exogenous IL-18 did not affect pathogen burdens in Il22−/− mice at 24 h (results not shown), it did significantly reduce infection-induced cecal goblet cell depletion compared to both WT and Il22−/− mice that did not receive IL-18 treatment (Figure 7a,b). The gene discussed is IL22; the disease is infection.