PROTEIN ASSAY METHOD SPECIFIC TO TRACP-5b (TARTRATE RESISTANT ACID PHOSPHATASE 5b)

The purpose of the present invention is to provide a monoclonal antibody that is useful in specifically assaying tartrate resistant acid phosphatase 5b (TRACP-5b). A hybridoma producing a monoclonal antibody against TRACP-5b, said monoclonal antibody showing higher reactivity with TRACP-5b than with tartrate resistant acid phosphatase 5a (TRACP-5a) and, therefore, being specific to TRACP-5b, is obtained by cell fusion using, as an antigen, human recombinant TRACP-5b purified from silkworm silk gland. By using this monoclonal antibody, TRACP-5b in a specimen can be highly sensitively and specifically detected.