Abstract Description Inflammatory bowel disease (IBD) is a chronic condition with rising prevalence and no known cure. The gut microbiota play a critical role in maintaining intestinal homeostasis and modulating the immune system, particularly through IL-10-producing regulatory T (Treg) and B (Breg) cells, which suppress inflammation. This study aimed to identify symbiotic microbes for managing gut inflammation by isolating Lactobacillus and Bifidobacterium strains from healthy human feces. Among the isolates, Bifidobacterium adolescentis (Bifi-94) significantly enhanced IL-10 production in vitro. Oral administration of Bifi-94 to mice for two weeks reduced weight loss and alleviated DSS-induced colon inflammation. In wild-type B6 mice, Bifi-94 increased IL-10 levels in colon homogenates without altering Treg cell subsets. CD19?CD11b? B1 cells in peritoneal exudate cells (PECs) were identified as the primary IL-10 source following Bifi-94 exposure. IL-10 secretion was triggered by live, heat-killed, and formalin-fixed Bifi-94. Peptidoglycan from Bifi-94 was identified as a key driver of IL-10 production in CD19?CD11b? B1 cells. Comparative analysis showed Bifi-94 expressed higher levels of peptidoglycan synthesis proteins, such as MurE, MurT, Alr, and UppP, than the reference strain KCTC3216. These findings suggest Bifi-94-derived peptidoglycan enhances IL-10 production, promotes Breg cell activity, and mitigates gut inflammation, highlighting its therapeutic potential for IBD. Funding Sources Supported by RS-2024-00338401; the Basic Science Research Program through the National Research Foundation of Korea (NRF). Topic Categories Mucosal and Regional Immunology (MUC)
Lee et al. (Sat,) studied this question.