(a) Haematoxylin and eosin staining of caecal sections from CD1, DBA/2, 129e, C3H and C57BL/6 mice after AIEC infection, and from uninfected controls. Images are representative of two experiments with four mice per time point. MM, muscularis mucosa; SM, submucosa; M, mucosa; L, lumen. Arrows indicate submucosa oedema, desquamation, hyperplasia, inflammatory cellular infiltrates and epithelial sloughing. (b) Caecal pathology was scored 3 weeks after infection. Scores represent an average of five views per section, and data are expressed as the means with s.d. for each group. Original magnification: × 200; scale bar, 200 μm.