Histoenzymatic activity of leucine aminopeptidase in normal bone marrow cells

Human, monkey, cat and rat bone marrow cells were studied for the histochemical localization of leucine aminopeptidase activity. The granulocytes have a weak enzymic activity in the immature cells and a very strong one in the differentiated cells. The lymphopoiesis is characterized by a strong reaction in the lymphoblasts and different degrees of the enzyme activity in the lymphocytes. In the erythropoiesis, the undifferentiated cells are strongly positive, while the erythrocytes are negative. The immature and mature cells of the megakariocytic line show a weak leucine aminopeptidase activity.