Fibroblast Growth Factor?18 (FGF-18) is a 20?kDa protein that plays an important role in skeletal development and bone homeostasis. It is expressed in embryonic somites and the neural fold, adult lung, cerebellar and hippocampal neurons. FGF-18 binds to FGF?R2c, FGF?R3c as well as the Golgi protein GLG1 and induces the proliferation of astrocytes and microglia, vascular endothelial cells, dermal fibroblasts, papilla cells, and keratinocytes. FGF-18 is required for normal skeletal development. A functional binding ELISA assay was conducted to detect the interaction of recombinant human FGF18 and recombinant human FGFR1. Briefly, FGF18 was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to FGFR1-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-FGF18 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 human FGF18 and recombinant human FGFR1 was shown in Figure 1, the EC50?for this effect is 0.26 ug/mL.