Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a hematopoietic growth factor produced by endothelial cells, monocytes, fibroblasts, and T cells.  GM-CSF stimulates the production of neutrophilic granulocytes, macrophages, and mixed granulocyte-macrophage colonies from bone marrow cells.  GM-CSF promotes immune system development and regulates neutrophil function during infection. 

Ships ambient. Store frozen at -20 to -10C.