Transferrin Receptor (TFR) , also known as cluster of differentiation 71 (CD71), is a type II transmembrane glycoprotein that plays a crucial role in the transport of iron into the cell. It binds to Transferrin (TRF), a carrier protein that transports iron in the blood, and facilitates the uptake of iron through endocytosis. This process is essential for many biological functions, including DNA synthesis and cell growth.Thus a functional binding ELISA assay was conducted to detect the interaction of recombinant human TFR and recombinant chicken TRF. Briefly, biotin-linked TFR were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100μl were then transferred to TRF-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST 3 times and incubation with Streptavidin-HRP for 30min, then wells were aspirated and washed 5 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50μl stop solution to the wells and read at 450nm immediately. The binding activity of TFR and TRF was shown in Figure 1, the EC50?for this effect is 0.068ug/mL.