ATG16L1 protects against cell death in the small intestinal epithelium. (A and B) Representative images (A) and quantification of Ki-67, TUNEL, and CC3 staining (B) of small intestine harvested from MNV-infected Atg16L1^f/f (f/f) and Atg16L1^ΔIEC (ΔIEC) mice on day 15 after MNV infection. Arrowheads indicate IECs positive for the indicated markers. Bars, 20 µm for TUNEL and 50 µm for Ki-67 and CC3 staining. At least 50 crypt–villus units were quantified per mouse from three mice per group. (C) Ki-67-, TUNEL-, and CC3-positive IECs were quantified as in B in small intestinal sections from Atg16L1^f/f and Atg16L1^ΔIEC mice on day 4 after allo-HSCT. At least 50 crypt–villus units were quantified per mouse from five mice per group. Data points in B and C represent individual crypts. Bars represent mean ± SEM, and at least two independent experiments were performed. ***, P < 0.001; ****, P < 0.0001 by unpaired t test.