Animal studies of colitis had demonstrated that B. fragilis NCTC 9343, B. thetaiotaomicron DSM 2079, and B. cellulosilyticus DSM 14838 improved intestinal histopathological injury and increased anti-inflammatory cytokine IL-10 and Treg cells levels by increasing the number of CD4+ CD45RBlow T cells (2, 59, 60). The gene discussed is IL10; the disease is colitis.