Granulocyte-macrophage
colony-stimulating factor （GM-CSF）, also known as colony-stimulating factor 2
（CSF2）, is a monomeric glycoprotein secreted by macrophages, T cells, mast
cells, natural killer cells, endothelial cells and fibroblasts that functions
as a cytokine. GM-CSF was first described as a growth factor that induces the
differentiation and proliferation of myeloid progenitors in the bone marrow,
which also has an important cytokine effect in chronic inflammatory diseases by
stimulating the activation and migration of myeloid cells to inflammation
sites, promoting survival of target cells and stimulating the renewal of
effector granulocytes and macrophages. GM-CSF receptor is composed of one α
chain and one β chain with low and high-affinity binding to GM-CSF,
respectively, and the β chain is shared with IL-3 and IL-5 receptor. GM-CSF
signals via signal transducer and activator of transcription, STAT5. In
macrophages, it has also been shown to signal via STAT3. The cytokine activates
macrophages to inhibit fungal survival.