For Western blot analysis, RANK receptor (19.3 kDa) was electrophoresed on SDS-PAGE using 10% acrylamide gel and transferred onto nitrocellulose membrane using mini trans-blot apparatus. The membrane was blocked with 5% skim milk in PBS-T for 1 h, washed with PBS-T, cut into strips, and incubated with purified mAb solution for 1 h. After washing, strips were reacted with GAM-HRPO for 1 h, and the binding of mAbs to RANK receptor was detected using enhanced chemiluminescence. For the negative control, the primary antibody was omitted, and the antigen strip incubated with PBS.