Disease severity of <i>Retnlb</i>^<i>-/-</i> mice is associated with greater <i>C</i>. <i>rodentium</i> invasion of colonic crypts.

<p>(A) <i>C</i>. <i>rodentium</i> enumeration in the colon tissue and luminal compartments of <i>Retnlb</i>^<i>-/-</i> and C57BL/6 following infection. Results show means of 3–4 (2 and 4 DPI) and 6–11 (6–10 DPI) animals, and are representative of 2 independent experiments **<i>P</i> = 0.0047, *<i>P</i> = 0.0262; ^##<i>P</i> = 0.0015 (<i>Retnlb</i>^-/- vs. C57BL/6); Mann-Whitney <i>U</i>-test. (B) <i>C</i>. <i>rodentium</i> staining in mouse colonic tissues (6 & 10 DPI). Original magnification = 200X. Results are representative of 4–6 mice/group. (C) Quantitation of <i>C</i>. <i>rodentium</i> LPS-filled crypts in <i>Retnlb</i>^<i>-/-</i> and C57BL/6 mice (10 DPI). Results represent mean of total crypts counted in single mice, pooled from 3–6 mice/group. *<i>P</i> < 0.05. (D) <u>Left panel:</u> H&E staining of heavily ulcerated colonic tissue from a <i>Retnlb</i>^<i>-/-</i> mouse (10 DPI). M = Mucosa; SM = submucosa. <u>Right Panel:</u> dual FISH staining using a universal EUB338 probe (red) and Gamma-proteobacteria specific probe (green), revealing clusters of <i>C</i>. <i>rodentium</i> (yellow) deep within ulcerated tissue, presumably where crypt bases were located. <i>Cr—C</i>. <i>rodentium</i>. Results are representative of all ulcerated <i>Retnlb</i>^<i>-/-</i> mice analyzed (n = 5). (E) Enumeration of systemic <i>C</i>. <i>rodentium</i> burdens in C57BL/6 vs. <i>Retnlb</i>^<i>-/-</i> mice (10 DPI). Each data point represents one animal. **P = 0.0037, Mann-Whitney <i>U</i>-test.