Interleukin 16 (IL-16), formerly known as lymphocyte chemoattractant factor or LCF, is a pro-inflammatory cytokine that is chemotactic for CD4 ?T lymphocytes, monocytes, and eosinophils. In addition to inducing chemotaxis, IL-16 can upregulate IL-2 receptor and HLA-DR4 expression, inhibit T cell receptor (TcR)/CD3-dependent activation, and promote repression of HIV-1 transcription.Besides,Interleukin 1 Alpha (IL1a) has been identified as an interactor of IL-16, thus a functional binding ELISA assay was conducted to detect the interaction of recombinant mouse IL-16 and recombinant dog IL1a. Briefly, IL-16 was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to IL1a-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-IL-16 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 450/630 nm immediately. The binding activity of recombinant mouse IL-16 and recombinant dog IL1a was shown in Figure 1, the EC50?for this effect is 1.9 ug/mL.