Fine Structural Localization of Acid and Alkaline Phosphatases in Cells of Rabbit Blood and Bone Marrow

In rabbit heterophils, acid phosphatase activity occurs in primary (azurophil) granules which predominate in early cells and persist in mature cells and in tertiary granules which are seen only in mature cells. Alkaline phosphatase activity occurs in secondary granules which appear in intermediate heterophils and later predominate in mature cells. Acid phosphatase activity in heterophil Golgi zones coincides developmentally with the genesis of primary and, later, tertiary granules, whereas alkaline phosphatase in the Golgi complex coincides with secondary granulogenesis. In developing eosinophils, acid phosphatase reaction product occurs in Golgi elements, rims the spherical precursors of angular, mature granules and appears inconsistently within mature granules. Basophil myelocytes show acid phosphatase in Golgi elements but not in specific granules. Additional acid phosphatase reactive structures include: granules of mononuclear cells; phagocytic vacuoles in macrophages; autophagic vacuoles in maturing erythroid cells; small dense granules of platelets; dense bodies in lipocytes; and Golgi elements of mononuclear cells, macrophages, nucleated red cells, megakaryocytes and lipocytes. Localized deposits were absent in control specimens except for enzyme-independent nuclear staining in alkaline phosphatase preparations.