Induction of Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) and Granulocyte Colony-Stimulating Factor (G-CSF) Expression in Bone Marrow and Fractionated Marrow Cell Populations by Interleukin 3 (IL-3): IL-3-Mediated Positive Feedback Mechanisms of Granulopoiesis

Abstract

Interleukin 3 (IL-3) induces proliferation and differentiation of mast cell progenitors in vitro, whereas it induces granulocytosis in vivo. In this paper, a positive feedback mechanism of granulopoiesis was studied in order to elucidate the granulocytosis induced by IL-3 in mouse. IL-3 induced expression of granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) in total bone marrow cells and a marrow adherent cell population. In fractionated marrow cell populations, a different expression pattern of induction by IL-3 stimulation was observed; GM-CSF was expressed in macrophages and fraction 1 (P<1.061) and 2(1.061