Localization of pyroantimonate-precipitable cation and surface coat anionic binding sites in developing erythrocytic cells and macrophages in normal human bone marrow

Summary The surfaces of developing erythrocytic cells and macrophages have been examined in normal human bone marrow by means of the pyroantimonate-osmium, ruthenium red and Thorotrast techniques for inorganic cations, surface glycoprotein-phospholipid complexes and surface anionic binding sites, respectively. No differences in the degree of surface coat reactivity were noted in the erythrocytic cells at different stages of maturation while pyroantimonate binding to the plasmalemma was not evident developmentally until the final stages of erythrocytic development. Rhopheocytotic invaginations proved to be chemically distinct from the remainder of the cell surface since they did not bind Thorotrast or pyroantimonate and gave more staining with ruthenium red. Pyroantimonate does not bind to the surface of macrophages and the binding of Thorotrast by these cells is less. Macrophage-erythrocytic cell contact zones did not stain with Thorotrast but stained with ruthenium red. The significance of these observations is discussed.Supported by Grant No. AM-HE-12084-14 from the National Institutes of Health, Bethesda, Maryland. — Appreciation is expressed to Anita Topson and Marjorie Griffith for their technical assistance and to Dr. Robert Hilberg for performing the bone marrow aspirations.