CHARACTERIZATION OF MONOCLONAL-ANTIBODIES SPECIFIC TO HUMAN TARTRATE-RESISTANT ACID-PHOSPHATASE

A major product of osteoclasts, tartrate-resistant acid phosphatase (T RAP) is an essential but insufficient enzyme for bone resorption, TRAP is an excellent cell marker for osteoclasts and macrophages and is be ing investigated as a serum marker for osteoclast activity in diseases of bone destruction, For decades, TRAP has also been used as a marker for hairy cell leukemia, Immunoassays for TRAP are sought to increase the sensitivity and specificity of the TRAP test for bone and hairy c ells, Our laboratory recently developed a monoclonal antibody to TRAP (9C5) useful for immunohistochemical identification of TRAP-positive c ells in paraffin sections, Herein, we characterize 9C5 in greater deta il and report production of another anti-TRAP monoclonal antibody (14G 6) reactive with native, active enzyme antigen, Enzyme immunoassay, im munoprecipitation, western blot, and immunohistochemical analyses reve aled the contrasting properties of 9C5 and 14G6, Antibody 9C5 reacts w ith a heat-denatured epitope and is suitable for denaturing western bl ot analysis and for immunohistochemistry. Antibody 14G6 reacts with a conformational determinant destroyed by heat and is suitable for immun oprecipitation of active TRAP, although 20% to 30% of activity is inhi bited in the immune complexes, Having characterized several properties of these anti-TRAP antibodies, 9C5 and 14G6 may be useful for develop ment of TRAP-specific immunoassays in bone pathology and hematology, T hey will certainly be of use for the study of biosynthesis, regulation , expression, and function of TRAP.