Interleukin-23 (IL-23) is a cytokine that belongs to the IL-12 cytokine family that is produced mainly by antigen-presenting cells. IL-23 receptor is expressed by various innate and adaptive immune cells, including group 3 innate lymphoid cells (ILC3), neutrophils, γδ T cells, Th17 and natural killer T (NKT) cells. IL-23 regulates various functions of the responding cells critical for host protective responses but is also implicated in many chronic inflammatory diseases including inflammatory bowel diseases (IBD). IL-23 receptor signaling components and downstream effector cytokines IL-17A/F, interferon-gamma (IFN-γ), IL-22, granulocyte macrophage colony–stimulating factor (GMCSF) have been shown to impact IBD-like disease development in various animal models; therapeutic approaches targeting the IL-23 pathway in IBD are in clinical trials. In this chapter, we attempt to review the literature on IL-23–mediated IBD pathogenesis. We did this by gathering the current information about the individual IL-23–producing and IL-23–responsive cells as to how they contribute to IBD pathology through various inflammatory mediators.
Part of the book: New Insights into Inflammatory Bowel Disease