The role of colony stimulating factor in the regulation of granulopoiesis.

: It is now clear that a variety of colony stimulating factors may be responsible for growth and maturation of progenitor cells in the marrow. Four of these CSFs have been purified to homogeneity with the distinct possibility of large-scale production of these factors by molecular cloning techniques. Studies of the binding and interaction of these factors with marrow cells are now under way. In vivo experiments with diffusion chamber techniques have shown the relevance of CSF in stimulating granulopoiesis when the progenitor cells are separated from their microenvironment but only limited effects in normal mice. This suggests that extensive microenvironmental influences may be involved in CSF-mediated granulopoiesis.