FIG. 3.

The serovar Typhimurium ΔwbaP strain (SKI12) is a potent inducer of colitis at day 2 p.i. Three groups of streptomycin-treated wild-type C57BL/6 mice (n = 5 per group) were infected for 2 days with the serovar Typhimurium wild-type strain (WT), ΔwbaP strain (SKI12), or ΔinvG strain (total of 5 × 10⁷ CFU intragastrically). Serovar Typhimurium colonization of cecum, MLNs, and spleen and cecal pathology were examined at day 2 p.i. (A to C) The number of serovar Typhimurium CFU in different organs (cecal content [A], MLNs [B], spleen [C]). Horizontal bars, median; dashed line, minimal detectable level; NS, not statistically significant (P ≥ 0.05). (D) Cecal pathology and its quantification at day 2 p.i. PMN, polymorphonuclear leukocytes. (E) Thin sections (5 μm) of cryoembedded cecal tissues were stained with H&E, as described in Materials and Methods. L, intestinal lumen; lp, lamina propria; S, submucosa. Scale bars, 200 μm.