RANK tumor necrosis factor receptor superfamily member 11A protein (TNFRSF11A) also known as receptor Activator of Nuclear Factor κ B (RANK) or TRANCE Receptoris a member of the tumor necrosis factor receptor (TNFR) molecular sub-family. TNFRSF11A is the receptor for RANK-Ligand (RANKL) and part of the RANK/RANKL/OPG signaling pathway that regulates oste°Clast differentiation and activation. It is ass°Ciated with bone remodeling and repair, immune cell function, lymph node development, thermal regulation, and mammary gland development. Besides, TNF Receptor Ass°Ciated Factor 5 (TRAF5) has been identified as an interactor of TNFRSF11A, thus a binding ELISA assay was conducted to detect the interaction of recombinant human TNFRSF11A and recombinant human TRAF5. Briefly, TNFRSF11A were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100µL were then transferred to TRAF5-coated microtiter wells and incubated for 2h at 37°C. Wells were washed with PBST and incubated for 1h with anti-TNFRSF11A 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 TNFRSF11A and TRAF5 was shown in Figure 1, and this effect was in a dose dependent manner.