The MaxDiscovery™ Human GM-CSF ELISA Test Kit is designed for quantitative determination of the concentration of human GM-CSF in serum, plasma, and cell culture supernatant. Human granulocyte/monocyte-colony stimulating factor (GM-CSF) is a 14 kDa protein composed of 127 amino acids. It was initially characterized as a growth factor that can support the in vitro colony formation of granulocyte-macrophage progenitors. It is differentially glycosylated factor produced mainly by activated T cells and macrophages. Endothelial cells and fibroblasts can also produce GM-CSF after exposure to TNF-a, IL-1, IL-2 and IFN-?. GM-CSF is found associated with extracellular matrix and in membrane-bound formats too. GM-CSF stimulates proliferation, activation and differentiation of macrophages and granulocytes and their progenitors.