Interleukin 23 (IL23)

Interleukin-23 (IL-23) is a heterodimeric cytokine composed of an IL12B (IL-12p40) subunit (that is shared with IL12) and the IL23A (IL-23p19) subunit. A functional receptor for IL-23 (the IL-23 receptor) has been identified and is composed of IL-12R β1 and IL-23R. Prior to the discovery of IL-23, IL-12 had been proposed to represent a key mediator of inflammation in mouse models of inflammation. However, many studies aimed at assessing the role of IL-12 had blocked the activity of IL-12p40, and were therefore not as specific as thought. Studies which blocked the function of IL-12p35 did not produce the same results as those targeting IL-12p40 as would have been expected if both subunits formed part of IL-12 only. The discovery of an additional potential binding partner for IL-12p40 led to a reassessment of this role for IL-12.