Murine hematopoietic stem cells committed to macrophage/dendritic cell formation: stimulation by Flk2-ligand with enhancement by regulators using the gp130 receptor chain.

The stimulation by Flk2-ligand (FL) of blast colony formation by murine bone marrow cells was selectively potentiated by the addition of regulators sharing in common the gp130 signaling receptor-leukemia inhibitory factor (LIF), oncostatin M, interleukin 11, or interleukin 6. Recloning of blast colony cells indicated that the majority were progenitor cells committed exclusively to macrophage formation and responding selectively to proliferative stimulation by macrophage colony-stimulating factor. Reculture of blast colony cells initiated by FL plus LIF in cultures containing granulocyte/macrophage colony-stimulating factor plus tumor necrosis factor alpha indicated that at least some of the cells were capable of maturation to dendritic cells. The cells forming blast colonies in response to FL plus LIF were unrelated to those forming blast colonies in response to stimulation by stem cell factor and appear to be a distinct subset of mature hematopoietic stem cells.