Interleukin-23 (IL-23) is a heterodimeric pro-inflammatory cytokine composed of two subunits: p19 (unique to IL-23) and p40 (shared with IL-12). Primarily produced by activated dendritic cells, macrophages, and other antigen-presenting cells, IL-23 plays a pivotal role in immune responses, particularly in promoting the differentiation and maintenance of T helper 17 (Th17) cells. Th17 cells secrete IL-17, IL-22, and other inflammatory mediators, which are crucial for host defense against extracellular pathogens but also contribute to autoimmune and chronic inflammatory diseases, such as psoriasis, inflammatory bowel disease (IBD), and rheumatoid arthritis.Besides,Janus Kinase 2 (JAK2) has been identified as an interactor of IL-23, thus a functional binding ELISA assay was conducted to detect the interaction of recombinant mouse IL-23 and recombinant rat JAK2. Briefly, IL-23 was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to JAK2-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-IL-23 pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody for 1h at 37℃, wells were aspirated and washed 5 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50 μL stop solution to the wells and read at 450/630nm immediately. The binding activity of recombinant mouse IL-23 and recombinant rat JAK2 was shown in Figure 1, the EC50?for this effect is 0.157μg/mL.