Description_x000D_ Biochem/physiol Actions_x000D_ Granulocyte-macrophage colony stimulating factor (GM-CSF) is a growth and differentiation factor for cells in the granulocyte, macrophage and eosinophil lineage. GM-CSF stimulates colony formation from pluripotential progenitor cells at extremely low concentrations and is an essential survival and proliferative factor for hematopoietic progenitor cells in all divisions up to maturity. It also stimulates growth in some epithelial cells and osteoclasts. GM-CSF is produced by a variety of cell types (monocytes, endothelial cells, T-cells, fibroblasts, mitogen-stimulated B-cells, and LPS-stimulated macrophages). GM-CSF is secreted as a single chain glycoprotein containing 128 amino acids for human with a conserved disulfide bond. Human and murine GM-CSF share approx. 54% sequence homology and do not cross-react in bioactivity._x000D_ Caution_x000D_ Although human and mouse GM-CSF share 54% amino acid sequence homology, their biological actions are species-specific and exhibit no cross-species reactivity._x000D_ Preparation Note_x000D_ HumanKine GM-CSF is expressed as a 15-36 kDa glycosylated monomer in human HEK 293 cells. Production in human HEK 293 cells offers authentic glycosylation. Glycosylation contributes to stability in cell growth media and other applications. Although human and mouse GM-CSF share 54% amino acid sequence homology, their biological actions are species-specific and exhibit no cross-species reactivity._x000D_ Analysis Note_x000D_ The specific activity was determined by the dose-dependent stimulation of the proliferation of human TF-1 cells (human erythroleukemic indicator cell line)._x000D_ Legal Information_x000D_ HumanKine is a registered trademark of HumanZyme Inc.