Interleukin-23 (IL-23) is a heterodimeric cytokine belonging to the IL-12 family that plays a critical role in regulating inflammatory and immune responses. In humans, IL-23 is primarily produced by activated antigen-presenting cells, such as dendritic cells and macrophages, in response to microbial stimuli. IL-23 signals through a receptor complex composed of IL-23R and IL-12Rβ1 subunits, leading to the activation of downstream signaling pathways, including the JAK-STAT pathway. IL-23 is known for its role in promoting the differentiation and expansion of pro-inflammatory T helper 17 (Th17) cells, which produce cytokines such as IL-17 and IL-22. Additionally, IL-23 contributes to the maintenance of immune homeostasis and has been implicated in the pathogenesis of autoimmune diseases, such as psoriasis, rheumatoid arthritis, and inflammatory bowel disease.