MUC2 and inflammatory bowel disease: The increased expression of truncated/immature glycans such as the Tn antigen on MUC2 protein is observed in patients with IBD.43–45 In line with these findings, we observed increased Tn antigen expression in the colon tissue of patients with UC and Il22Ra1Math1-PGR mice, which may also indicate less sialylation (α2–6) of the Tn antigen.22 Thus, it is likely that B3GALT5 elongates the core-2 structure and promotes α2–6 sialylation.