Two Monoclonal Antiplatelet Antibodies as Markers of Human Megakaryocyte Maturation: Immunofluorescent Staining and Platelet Peroxidase Detection in Megakaryocyte Colonies and in In Vivo Cells From Normal and Leukemic Patients

Two monoclonal anti-human platelet antibodies have been used in an immunofluorescent assay to study megakaryoCyte maturation. The two antibodies were specific for platelets and megakaryocytes. AN 51 recognizes an antigen on platelet glycoprotein Ib; the antigen detected by J 1 5 is on the glycoprotein llb/Illa complex. since it does not bind to platelets from patients with Glanzmann’s thrombasthenia. AN 51 did not stain small cells of normal bone marrow. but it labeled most of the megakaryocytes and all of the platelets. In megakaryocyte colonies, megakaryocytes that had reached full maturity (at day 1 2 of culture) were stained specifically. AN 51 also labeled micromegakaryocytes (small mature megakaryocytes) in fetal or neonatal cultures and in leukemias. but could not be applied to identification of most leukemic promegakaryoblasts. In contrast, J 1 5 labeled all megakaryocytes in bone