IL-12 and IL-23 are required for resistance against S. Typhimurium (Stym).

<p>WT, p19^−/−(no IL-23), p35^−/−(no IL-12), and p40^−/− (no IL-12/-23) mice were orally infected with 1×10³ CFU of <i>S</i>. Typhimurium 1 day after 20 mg streptomycin pretreatment. (A) Cecum and (B) liver were collected from infected mice 3 days post infection. Organs were weighed, homogenized and plated to determine CFU/organ. Bars represent the median bacterial load. Pooled data from 3 separate experiments are shown in A and B. (C) Representative ceca are shown for each group at 3 d after oral inoculation with PBS (mock) or Stym. A one centimeter bar indicates the magnification. (D) 10X and (E) 40X magnification of histopathology of H&E stained cecal sections of WT, p19^−/−, p35^−/−, and p40^−/− mice 3 d after infection. Bar in (D) represents 100 micron and (E) 20 micron. Notched arrow-heads in (E) indicate cell death. (F) Blinded scoring was performed on H&E-stained cecal sections. The inflammatory score equals the sum of the separate categories (edema, PMN infiltration, lymphoplasmacytosis, and goblet cell loss). (G) H&E stained cecal sections from WT, p19^−/−, p35^−/−, and p40 mice 3 d after infection were blinded and qualitatively assessed for cell death: 0 (no significant), 1 (focal), 2 (mild), 3 (severe) in the basal epithelium. At least 3 mock treated animals and at least 13 infected mice from each group from 3 separate experiments were scored in 1F and 1G. Mean values ± SE are shown. Statistical significance was determined using the one way ANOVA test with Bonferroni post test (A, B, F and G). *: p<0.05, **: p<0.01, ***: p<0.001.