Immunopathogenesis of inflammatory bowel disease

Figure 4 Differentiation of T-cell Subsets. Upon stimulation, naïve CD4+ T-cells differentiate into 3 main subsets, Th1, Th2, and Th17 cell. IL-12 induces the formation of IFN-γ producing Th1 cells. IL-23 promotes the development of an IL-17 producing CD4+ helper T cells. IL-4 induces STAT6 activation, promoting the expression of GATA-3, which feed forward to induce IL-4 expression and Th2 cell differentiation. An EBI3-associated cytokine was hypothesized to be necessary for activation of IL-13 producing NK T-cells. Tregs, an immune-modulating subset of CD4+ T-cells, can suppress the differentiation and function of Th1 and Th2 cells. Interestingly, in the presence of IL-6, Treg-derived TGF-β can induce the differentiation of Th17 cells.