Figure 3 Reciprocal developmental pathways for the generation of pathogenic effector T Th17 cells and regulatory T cells. At the steady‐state level TGF‐β produced in the immune system will suppress the generation of effector T cells and induce Foxp3⁺ regulatory T cells, and thereby maintain self‐tolerance. However, on infection or inflammation, IL6 produced by the activated innate immune system suppresses the generation of TGF‐β‐induced Treg cells and induces pro‐inflammatory Th17 cells.