MOLECULES

Full name: Interleukin-23

Aliases: IL-23A, P19, SGRF, and IL23P19¹

Size: ~59 kDa; heterodimeric cytokine composed of IL-12B (IL-12 p40) and IL-23A (IL-23 p19)^1,2

Family: IL-12 family (IL-12, IL-23, IL-27, and IL-35)³

Receptors: IL-23R²

Major cellular sources: Phagocytic cells, macrophages, and activated DCs from peripheral tissues, including the skin, intestinal mucosa, and lungs²

Major cellular targets: T cells, Th17 cells, NK cells, NKT cells, eosinophils, monocytes, macrophages, DCs, and epithelial cells²

Disease states associated with: Psoriasis and organ-specific autoimmune diseases²

Major physiologic functions:

• Along with stimulation of memory T cells, the key functions of IL-23 include the stimulation of pro-inflammatory IL-17 production, enhancement of T-cell proliferation, and activation of NK cells.²
• IL-23 is responsible for the regulation of antibody production.²
• IL-23 prolongs the expression of type 17 signature cytokines such as IL-17, IL-22, and GM-CSF that induce tissue pathology.³
• IL-23 mediates chronic inflammation by promoting the survival and maintenance of Th17 cells.³
• IL-23 has an important role in immunopathogenic mechanisms of organ-specific autoimmune diseases.³
• IL-23 contributes to the development of Th17 cells, and a population of ILCs responds to IL-23 and might have a role in inflammatory bowel disease pathogenesis.²

DC: dendritic cell; GM-CSF: granulocyte-macrophage colony-stimulating factor; IL: interleukin; IL-23R: IL-23 receptor; ILC: innate lymphoid cell; NK: natural killer; NKT: natural killer T; Th17: type 17 T helper.