Applications and performance of monoclonal antibodies to human tartrate resistant acid phosphatase.

Background: Tartrate-resistant acid phosphatase (TRACP) is an enzyme common to cells of the mononuclear phagocyte system and a clinically relevant biomarker for osteoclasts and inflammatory macrophages. The purpose was to assess applications and performance of six anti-TRACP monoclonal antibodies.

Methods: Mab9C5, 14G6, 162, 203, 220, and 89 were used as capture and detection antibodies in quantitative immunoassay, and for western blot (WB), immunoprecipitation, and immunohistochemistry of paraffin sections containing chronic inflammatory infiltrates. The clinical performance of mab14G6 for immunoassay of serum TRACP5b activity was compared to two commercial kit methods.

Results: Mab9C5 is useful for WB and immunohistochemistry methods only. Mab14G6, 162, and 203 are useful for quantitative immunoassay and immunoprecipitation, however, mab203 causes inactivation of enzymatic activity. Mab220 and 89 are specific for TRACP5a and useful in all applications. Mab14G6 has similar clinical sensitivity and specificity as two commercial methods.

Conclusions: TRACP is an important marker in osteoimmunology. Specific antibodies with unique specificity for TRACP isoforms and defined applications will be valuable for clinical evaluation of bone metabolic, inflammatory and autoimmune diseases and will aid in basic research of TRACP biochemistry and biology.