We demonstrate B10 cells induced by ManLAM regulate Th1/Th2 cytokine balance and decrease severity of IBD compared with ManLAM‐IL‐10−/− B cell group, suggesting that ManLAM‐treated B cells have a preventive effect on colitis and this beneficial effect is mediated via IL‐10 production. The gene discussed is IL10; the disease is inflammatory bowel disease.