Interferon tau (IFNτ), a ruminantspecific typeI interferon secreted by conceptus trophectoderm, serves as the core signal for maternal pregnancy recognition. It triggers JAKSTAT cascades to exert immunomodulatory, antiproliferative and antiviral bioactivities. Beyond canonical receptor engagement, IFNτ exhibits direct physicalbinding activity toward 3Mercaptopyruvate Sulfurtransferase (MST).
Thus a functional ELISA assay was conducted to detect the interaction of recombinant IFN-τ and recombinant MST. Briefly, IFN-τ was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μL were then transferred to MST-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-IFN-τ 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 IFN-τ and recombinant MST was shown in Figure 1, the EC50?for this effect is 0.426 μg/mL.