Cells with Fc gamma receptors from normal donors suppress granulocytic macrophage colony formation

Abstract

Abstract We investigated the role of normal human marrow cells with Fc receptors for IgG (Fc gamma+) on autologous granulocyte-macrophage colony (GM- CFC) formation. It was found that Fc gamma+ normal human marrow cells, both with (E+) or without receptors for sheep erythrocytes suppressed GM-CFC at as low a concentration as 0.25 X 10(5) cells/ml of culture. A similar effect was observed with E- Fc gamma+ but not E+ Fc gamma+ peripheral blood cells. Suppression by Fc gamma+ cells did not require mitogen activation and was not inactivated by irradiation (2000 R). This report presents a new in vitro regulatory mechanism for GM-CFC growth in normal donors.