Interleukin-17 receptor A (IL17RA) is a cytokine receptor which binds interleukin 17A (IL17A). IL17A is a proinflammatory cytokine secreted by activated T-lymphocytes. IL17RA, as a transmembrane protein, is a ubiquitous type I membrane glycoprotein that binds IL17A, IL17F and IL17C. Activation of IL17RA leads to induction of expression of inflammatory chemokines and cytokines such as CXCL1, CXCL8/IL8 and IL6. Thus a binding ELISA assay was constructed to detect the association of recombinant human IL17RA with recombinant human IL17A. Briefly, IL17RA were diluted serially in PBS, with 0.01%BSA (pH 7.4). Duplicate samples of 100uL were then transferred to IL17A-coated microtiter wells and incubated for 2h at 37°C. Wells were washed with PBST and incubated for 1h with anti-IL17RA 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°C. Finally, add 50µL stop solution to the wells and read at 450nm immediately. The binding activity of IL17RA with IL17A was shown in Figure 1 and this effect was in a dose dependent manner.