The macrophage colony-stimulating factor (MCSF), also designated CSF-1, was originally discovered in serum, urine and other biological fluids as a factor that can stimulate the formation of macrophage colonies from bone marrow hematopoietic progenitor cells. MCSF is a glycoprotein required for the proliferation and differentiation of mononuclear phagocytes, including osteoclasts. MCSF has also been identified as an important mediator of the inflammatory response and can regulate the release of proinflammatory cytokines from macrophages.
