Recombinant Human Granulocyte Macrophage Colony StimulatingFactor (rHu GM-CSF) is produced in response to a number of inflammatorymediators by mesenchymal cells present in the hemopoietic environment and atperipheral sites of inflammation. GM-CSF is able to stimulate the production ofneutrophilic granulocytes, macrophages, and mixed granulocyte-macrophagecolonies from bone marrow cells and can stimulate the formation of eosinophilcolonies from fetal liver progenitor cells. GM-CSF can also stimulate somefunctional activities in mature granulocytes and macrophages. rHu GM-CSFreceptors show significant homologies with other receptors for hematopoieticgrowth factors, including IL2-beta, IL-3, IL-6, IL-7, EPO and the Prolactinreceptors. rHu GM-CSF produced in E. coli is a single, non-glycosylated,polypeptide chain that contains 127 amino acids and has a molecular mass of14.48 kDa. The product is very stable for up to three years from manufacturingdate, when stored lyophilized at -20° C.