Interferon-alpha 2 (IFN alpha -2), one of 14 subtypes within the IFN-alpha class of Type I Interferons, was the first to be cloned in the early eighties. The size of the mature IFNα2 is thus 165 amino acids, which is one amino acid shorter than all other human IFNα subtypes. And it is Produced by macrophages, IFN-alpha have antiviral activities and is involved in cytokine storm inflammatory response. Janus Kinase 1 (JAK1), a kind of tyrosine kinase of the non-receptor type, is involved in the IFN-alpha/beta/gamma signal pathway. Thus a functional binding ELISA assay was conducted to detect the interaction of recombinant mouse IFNα2 and recombinant human JAK1. Briefly, IFNα2 was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to JAK1-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti- IFNα2 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 IFNα2 and recombinant human JAK1 was shown in Figure 1, and this effect was in a dose dependent manner.