Innate immunity restricts Citrobacter rodentium A/E pathogenesis initiation to an early window of opportunity
Fig 2
High-dose C. rodentium infection is associated with reduced severity of disease in germ-free wild-type mice.
(A) Body weight of germ-free mice infected with either 104 (blue circles) or 1010 (red squares) CFU/mouse of C. rodentium, (n = 15 until day 10). (B) Survival curve of the animals shown in A. (C) Splenic bacterial loads of mice shown in A infected with 104 (blue circles) or 1010 (red squares) CFU/mouse of C. rodentium for 10–13 days; n = 10–12 per group. (D) Histopathological scores of mice shown in panel A (Endpoint criterion: weight loss of >20 %). Mice were scored for epithelial hyperplasia and integrity, infiltration of PMNs, submucosal edema, and loss of goblet cells. Graph shows combined score (= sum of 5 individual scores). (E) Representative images of colonic histopathology scored in panel D (H&E staining) of mice infected for 13 days with 104 (top) and 1010 (bottom) CFU. Arrows in panel D indicate the individuals depicted. Scale bar: 100 μm; Sm, submucosa; Cr, crypts; Ep, epithelium; Lp, lamina proria; (F) Lipocalin-2 measurement by ELISA in feces from infected mice (n = 5 per group, same animals as shown in A; after day 13 n = 3 survivors in 104 group). Error bars indicate standard deviation. Dotted lines indicate detection limit; ns, statistically not significant; *, p < 0.05; **, p < 0.01; ***, p < 0.001; ****, p < 0.0001; statistical tests: Student`s t-test (A), Mantel-Cox test (B), Mann-Whitney U test (C, D, F).