Recombinant human sRANK receptor is a 19.3 kDa polypeptide. It was electrophoresed on a 10% polyacrylamide gel and transferred to nitrocellulose membrane. On incubation with generated mAb, a band was detected between 15 and 20 kDa, after the chemiluminescent detection of anti-RANK IgG (Fig. 4) .