Von Willebrand Factor (vWF) , a large multimeric plasma glycoprotein , is synthesized mainly by endothelial cells and megakaryocytes. The protein consists of multiple subunits, forming high - molecular - weight multimers. These multimers have emerged as a key player in both primary and secondary hemostasis.During coagulation, coagulation factor VIII (F8) can bind to vWF, and this interaction plays a crucial role in prolonging the half-life of vWF, regulating its activity, and targeting transport.Thus a functional ELISA assay was conducted to detect the interaction of recombinant mouse vWF and recombinant dog F8. Briefly, vWF was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to F8-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-vWF 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 mouse vWF and recombinant dog F8 was shown in Figure 1, the EC50 for this effect is 0.36ug/mL.