IL-23 p19

Class

IL-23 inhibitor

Pathway

IL-23 / Th17

IL-23 is a cytokine built from two protein subunits, p19 and p40, that together bind a receptor complex present on T helper 17 (Th17) cells and related innate immune cells. This signal sustains Th17 cells and drives their production of inflammatory messengers, notably interleukin-17 and interleukin-22, in a pathway referred to as IL-23/Th17. Overactivity of this axis contributes to chronic tissue inflammation seen in psoriasis, psoriatic arthritis, and inflammatory bowel diseases such as Crohn's disease and ulcerative colitis. Because p19 is unique to IL-23, antibodies engineered to bind p19 neutralize IL-23 specifically, in contrast to agents that target the shared p40 subunit, which also blocks interleukin-12, a related cytokine with distinct immune functions. The rationale for p19-selective inhibition is to interrupt the Th17-driven inflammatory cycle at its source while sparing pathways not implicated in the disease, aiming for durable control of inflammation across skin, joints, and intestinal tissue. Some newer molecules combine IL-23 blockade with inhibition of other inflammatory mediators, such as TNF-alpha or TL1A, reflecting efforts to address overlapping inflammatory pathways in cases where IL-23 alone does not account for the full disease process.