IL-10 KO Treg-of-B cells successfully suppressed responder T cell proliferation (Fig. 4A); moreover, IL-10 KO Treg-of-B cells were able to attenuate chronic colitis induced by the colitogenic T cells (Fig. 5) and suppress the Th1 and Th17 response (Fig. 6). The gene discussed is IL10; the disease is Chronic colitis.