(A) Mouse body weight change kinetics after AOM-DSS treatment.
(B) Colon tissues at the indicated time points were stained by H&E and analyzed for inflammation and tumor development. Bottom panels show magnified images (scale bar: 320 μM) of the top panels (scale bar: 130 μM) in both WT and PD-L1 KO panels. Inflammation scores are defined as grade 0, normal colonic mucosa; grade 1, loss of one-third of the crypts; grade 2, loss of two-thirds of the crypts; grade 3, lamina propria is covered with a single layer of epithelium, mild inflammatory cell infiltrate present; grade 4, erosions and marked inflammatory cell infiltration present. AIS, adenocarcinoma in situ.