Syndecan-4 (SDC4), a transmembrane proteoglycan bearing heparan sulfate chains, is an important member of SDCs family.SDC4 is expressed on dendritic cells (DCs) and activated T cells, plays a crucial role in DC motility and has been shown as a potential target for activated T-cell-driven diseases.SDC4 is involved in numerous inside-out and outside-in signaling processes, such as binding and sequestration of growth factors and extracellular matrix components, regulation of the activity of the small GTPase Rac1, protein kinase C-alpha, the level of intracellular calcium, or the phosphorylation of focal adhesion kinase. A functional binding ELISA assay was conducted to detect the interaction of recombinant human Fibroblast Growth Factor 2, Basic (FGF2) and recombinant human SDC4. Briefly, biotin-linked SDC4 were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100 ul were then transferred to FGF2-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 450 nm immediately. The binding activity of recombinant human SDC4 and recombinant human FGF2 was shown in Figure 1, the EC50?for this effect is 1.45 ug/mL.