The Interferon-alpha (IFNa) proteins belong to type I interferons (IFNs) which a large subgroup of interferon proteins that help regulate the activity of the immune system. The IFNa proteins produced by leukocytes are also known as leukocyte interferon. They are mainly involved in innate immune response against viral infection. Besides, Interferon-alpha 13 (IFNA13) has been identified as an interactor of IFNa, thus a binding ELISA assay was conducted to detect the interaction of recombinant mouse IFNa and recombinant mouse IFNA13. Briefly, IFNA were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100uL were then transferred to IFNA13-coated microtiter wells and incubated for 2h at 37 degree C. Wells were washed with PBST and incubated for 1h with anti-IFNapAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody, wells were aspirated and washed 3 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37 degree C. Finally, add 50uL stop solution to the wells and read at 450nm immediately. The binding activity of IFNa and IFNA13 was shown in Figure 1, and this effect was in a dose dependent manner.