①Measured by its binding ability in a functional ELISA. Immobilized TNFRSF18 at 2 μg/ml can bind TNFSF18 , the EC50 is 2.565 to 2.940 ng/ml.②Human TNFRSF18 protein hFc tag captured on COOH chip can bind Human TNFSF18 protein hFc and Flag tag with an affinity constant of 38.5 nM as detected by LSPR Assay.