FIG 2.

Infant susceptibility to C. rodentium infection is associated with late severe inflammation in the colon and systemic dissemination. Infants (INF) and adults (AD) were orally infected with 10⁷ and 5 × 10⁸ CFU, respectively, of C. rodentium and examined 10 days p.i. (A) Colon sections were stained with hematoxylin & eosin and examined for inflammation; 4 mice in each group were examined. Scores were determined on a scale of 0 to 3 (0, none; 1, mild; 2, moderate; and 3, severe). Of note, the pathologist was given only numbers for each sample and was unaware of any specifics of the experiments. INFLAM, inflammasomes; LYMPH, lymphocytes; MONO, monocytes; NEUT, neutrophils. (B) Representative sections of colons. AD, mild inflammation limited to the mucosal surface; INF, severe inflammation with necrosis extending from the mucosa to the submucosa and muscularis. Magnification, ×50. (C) Organs were dissected and homogenized for CFU counts. COL, colon; MLN, mesenteric lymph nodes; SP, spleen; LIV, liver. Each symbol represents an individual mouse. *, P ≤ 0.01 by Mann-Whitney analysis. ns, not significant.