Asporin (ASPN) is a protein belongs to a family of leucine-rich repeat (LRR) proteins implicated in cancer, osteoarthritis, and periodontal ligament mineralization. The protein negatively regulates chondrogenesis in the articular cartilage and periodontal ligament (PDL) differentiation, inhibits BMP2-induced cytodifferentiation of PDL cells and also nhibits the interaction between TGFB1 and TGF-beta receptor type II in the presence of heparin/heparan sulfate in vitro. In addition Lumican (LUM) and ASPN can contribute to the fibrinogenesis of cardiac remodeling of ICM, thus a binding ELISA assay was conducted to detect the interaction of recombinant mouse ASPN and recombinant mouse LUM. Briefly, ASPN were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to LUM-coated microtiter wells and incubated for 2h at 37℃. Wells were washed with PBST and incubated for 1h with anti-ASPN pAb, 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℃. Finally, add 50 μL stop solution to the wells and read at 450 nm immediately. The binding activity of recombinant mouse ASPN and recombinant mouse LUM was shown in Figure 1, the EC50?for this effect is 2.6 ug/mL.