Figure 5.

Colonic histopathology during Clostridium difficile infection in the absence of interleukin‐17 (IL‐17) or following anti‐IL‐22 treatment. Representative photomicrographs of haematoxylin & eosin‐stained colonic sections from wild‐type (WT) C. difficile‐infected, C. difficile‐infected and anti‐IL‐22‐treated, and IL‐17KO C. difficile‐infected animals. Cross‐sections of colonic crypts (upper images) and longitudinal sections of the epithelial–luminal interface (lower images) are shown for each genotype. Black arrowheads highlight leucocytic infiltrate, and grey arrowheads highlight areas of epithelial damage. Total magnification for all images is 400×. (b–d) Histopathological scoring of colonic sections from Untreated, WT CDI, CDI + anti‐IL‐22, and IL‐17KO CDI mice. Slides were scored for neutrophilic inflammation (b), oedema (c), and epithelial damage (d) as described in the Materials and methods. Data are shown as mean ± SEM. n ≥ 6 per group. CDI = C. difficile infected. Brackets indicate P < 0·05 for the differences between indicated groups.