Mononuclear phagocytes from human bone marrow progenitor cells; morphology, surface phenotype, and functional properties of resting and activated cells.

After 3-4 weeks culture of human bone marrow cells in medium supplemented with IL-3, macrophage- (M-CSF), and granulocyte-macrophage colony-stimulating factor (GM-CSF), the firmly adherent cells exhibited the morphologic features of mononuclear phagocytes and were strongly esterase-positive. Flow cytometric analysis revealed a rather homogeneous cell population with marked autofluorescence; the large majority of the cells expressed CD14, CD11a, b, and c, Fc receptors for IgG, Fc gamma RI, II, and III, and HLA class II molecules. Interferon-gamma (IFN-gamma), bacteria, and bacterial products modulated expression of some of the surface markers, induced and/or enhanced respiratory burst, phagocytic activity, secretion of tumour necrosis factor, and tumouricidal activity; in contrast, these cells were not able to generate reactive nitrogen intermediates.