Current understanding of the role of tyrosine kinase 2 signaling in immune responses

Figure 2 Schematic representation of naïve T cell differentiation into T helper 1, T helper 2, or T helper 17 cells depending on the cytokine profile. IL-12 promotes the differentiation of naïve T cells into Th1 cells. Th1 cells promote the clearance of intracellular pathogens and induce autoimmunity through the production of IFN-γ, IL-2, and TNF-α. Th1 differentiation is regulated by transcription factors such as signal transducer and activator of transcription (STAT)1, STAT4, and T-bet. IL-4 promotes the differentiation of naïve T cells into Th2 cells. Th2 cells promote the clearance of extracellular pathogens and induce allergic responses through the production of IL-4, IL-5, IL-6, and IL-13. Th2 differentiation is regulated by transcription factors such as STAT6 and GATA3. TGF-β, IL-6, and IL1 promote the differentiation of naïve T cells into Th17 cells, while IL-23 can maintain the Th17 phenotype. Th17 cells promote the clearance of extracellular pathogens and induce autoimmunity through the production of IL-17, IL-21, and IL-22. Th2 differentiation is regulated by transcription factors, such as STAT3, RORγt and RORα.