MONOCLONAL-ANTIBODY WGM1 DIRECTED AGAINST PROTEINASE-3 - AN IMMUNOHISTOCHEMICAL MARKER FOR NAPHTHOL ASD CHLOROACETATE

Enzyme histochemistry for naphthol ASD chloroacetate (NASDCA, Leder's stain') is used to identify the granulocyte lineage ranging from promy elocytes to mature neutrophils and is an additional tool for the chara cterization of leukemias. We demonstrated for the first time that NASD CA activity can be detected by routine immunohistochemistry and immuno cytochemistry using the monoclonal antibody WGM1 directed against prot einase 3 (PR3; synonyms: Wegener's autoantigen, myeloblastin). Immunoh isto- and immunocytochemical staining with WGM1 against PR3 and enzyme histochemistry for NASDCA produced identical staining patterns in nor mal myelomonocytic cells and cells of myeloid leukemia. This was addit ionally proven by double immunostainings. We have also shown that PR3 is one of the specific proteinases responsible for hydrolysis of NASDC A.