Clonal Analysis of Proliferation and Differentiation of Paired Daughter Cells: Action of Granulocyte-macrophage Colony-stimulating Factor on Granulocyte-macrophage Precursors

Mouse granulocyte-macrophage progenitor cells were stimulated to divide by the granulocyte-macrophage colony-stimulating factor (GM-CSF). The two daughter cells were separated; one daughter was transferred to medium containing a high concentration of GM-CSF, the other to medium containing a low concentration. Daughter cell-derived clones in the presence of 2500 units of GM-CSF had average cell cycle times 3.5 +/- 2.5 (SEM) hr shorter than clones derived from the paired daughter cell stimulated by 50 units of GM-CSF. Final colony size achieved after stimulation by 50 units of GM-CSF was always smaller than that of colonies stimulated by 2500 units of GM-CSF. In 8 of 41 instances, colonies stimulated by 50 units of GM-CSF developed, or were composed only of, macrophage populations in contrast to the granulocytic composition of colonies derived from the paired daughter cell growing in the presence of 2500 units of GM-CSF. The regulator GM-CSF appears able to directly influence cell cycle times and the pathway of differentiation entered by many bipotential granulocyte-macrophage precursor cells.