Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a protein secreted by macrophages, T cells, mast cells, NK cells, endothelial cells and fibroblasts. GM-CSF stimulates stem cells to produce granulocytes (neutrophils, eosinophils, and basophils) and monocytes. Granulocyte macrophage–colony stimulating factor (GM-CSF) is secreted in response to inflammatory stimuli such as LPS, IL-1, and TNF-α by a variety of different cells, including endothelium, fibroblasts, muscle cells, and macrophages, and by activated T cells. GM-CSF is glycosylated in its mature form.

The biological activity of recombinant mouse GM-CSF was measured in a cell proliferation assay using the mouse FDC-P1 cell line. The ED50 for this effect is typically 0.0015  - 0.0023ng/mL.

Alternate Names - CSF2, GMCSF, colony stimulating factor 2, CSF