[Stem cell factor].

Stem cell factor (CSF), also called c-kit ligand (KL) or mast cell growth factor (MGF) is a peptide growth factor/cytokine with broad activities, especially on hematopoiesis. Its physiological role is best understood through the naturally occurring steel and W mutations in the mouse. This cytokine has recently been made available because of molecular cloning and its expression in recombinant form SCF is produced by a variety of cells, especially fibroblast, and interacts with target cells in each of the hematopoietic lineages to stimulate proliferation and differentiation. It has been found that SCF is important for the survival, proliferation and differentiation of mast cells and that it influences all stages of their development. SCF activity is not restricted to hematopoiesis, as it plays an important role in the development of germ cells and melanocytes as well. Preclinical studies show that SCF can protect against lethal irradiation, elicit multilineage responses in peripheral blood and bone marrow cellularity and increase circulating peripheral blood progenitor cells in a dose-dependent manner. Recombinant human SCF has major clinical potential through its synergy with other factors, especially G-CSF, to enhance mobilization of stem cells in peripheral blood.