IL-12

Interleukin-12 (IL-12) is a receptor for IL-12R and belongs to the type I cytokine receptor family, subfamily 4. This cytokine acts as a growth factor for activated T and NK cells, enhances the lysate activity of natural killer cells or lymphokine-activated killer cells, and stimulates IFN-γ production through resting PBMC. Il-12β (IL-12B) is the main functional chain of IL-12. It can heterodimerize with IL-12 p35 subunit (IL-12A) to form IL-12, or with IL-23 p19 subunit (IL23A) to form IL-23^[1]. IL-12 and IL23 belong to the IL-12 family, participate in proinflammatory response, and are expressed by activated macrophages, and play different regulatory functions as necessary inducers of Th1 cell development^[2]. More importantly, IL-23 is a heterodimer factor that plays a role in innate and adaptive immunity and may, together with IL-17, constitute the acute response of peripheral tissue to infection. In terms of signal transduction, IL-12 signaling is mediated by p-STAT4, while IL-23 signaling is regulated by IL-23 binding by p-STAT1 and p-STAT3^[3]. Moreover, the heterodimer receptor complex composed of IL12RB1 and IL23R further activates the Jak-STAT signaling cascade, stimulates memory rather than naive T cells, and promotes the production of pro-inflammatory cytokines. IL-23 induces autoimmune inflammation, so it may lead to autoimmune inflammatory diseases^[4].