IL17A and colitis: In the present study, administration of B. adolescentis IF1-03 increased the distribution of Treg cells, and IL-10 producing macrophages in the lamina propria, protecting the mice from DSS-induced colitis in vivo, whereas B. adolescentis IF1-11 upregulated the differentiation of IL-17A without any amelioration of DSS-colitis, in accordance with the in vitro results and physiological functions of Treg and Th17 cells [38].