Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine that has been characterized as a molecule capable of stimulating proliferation and differentiation of granulocyte/macrophage progenitor cells as well as modulating the functional activity of mature granulocytes and macrophages. In combination with erythropoietin, it supports the development of erythroid progenitors in vitro. The biological activities of GM-CSF substantially overlap with the effects of Interleukin 3. The reason for the redundancy of these pleiotropic cytokines may at least in part be explained by their competition for binding to common receptors. GM-CSF is produced by a number of different cell types such as activated T-cells, B-cells, macrophages, mast cells, endothelial cells, fibroblasts, synoviocytes and various tumor cells in response to various stimuli. Mouse GM-CSF as well as its receptors have been cloned. The encoded glycoprotein consists of 141 amino acid residues and has a molecular weight of about 23 kDa. The murine protein binds to a high affinity receptor complex consisting of two membrane glycoproteins, the GM-CSF receptor alpha subunit with notable homology to the human receptor and the beta subunit which also forms part of the receptors for IL-3 and IL-5. Elevated levels of GM-CSF are found in mice after endotoxin injection.

Synonyms: Molgramostin, Sargramostim