7.1.6　Interleukin-12

IL-12 is mainly produced by activated antigen-presenting cells such as DCs, macrophages,monocytes and B cells.IL-12 production is a tightly controlled process, regulated mainly at the transcriptional level.Production is initiated by activation of pathogen recognition receptors such as Toll-like receptors in antigen-presenting cells upon sensing of pathogen-associated molecular patterns) or damage-associated molecular patterns.In addition, cytokine stimulation and direct immune cell-cell contact, including CD40-CD40L interactions, induce IL-12 production.This latter CD40-dependent mechanism is likely to be the principal mechanism for the production of IL-12 in cancer.IL-12 binds to the IL-12 receptor (IL-12R), expressed as a high-affinity heterodimer of IL-12Rβ1 and IL-12Rβ2 subunits mostly on T cells and NK cells.The β1 subunit is constitutively expressed on immune cells, whereas the β2 subunit is upregulated in T cells and NK cells upon activation.(https://www.daowen.com)