Interleukin-2 (IL-2) is a critical cytokine primarily produced by activated T cells that plays a fundamental role in regulating immune responses. It stimulates the proliferation and differentiation of T cells, B cells, and natural killer (NK) cells, making it essential for both innate and adaptive immunity. IL-2 exerts its effects by binding to the IL-2 receptor (IL-2R), which consists of three subunits , triggering downstream signaling pathways such as JAK-STAT, PI3K, and MAPK.Besides,Interleukin 1 Beta (IL1b) has been identified as an interactor of IL-2, thus a functional binding ELISA assay was conducted to detect the interaction of recombinant goat IL-2 and recombinant rat IL1b. Briefly, IL-2 was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to IL1b-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-IL-2 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 goat IL-2 and recombinant rat IL1b was shown in Figure 1,and this effect was in a dose dependent manner.