G-CSF (granulocyte-colony stimulating factor) is a secreted glycoprotein that regulates the proliferation, differentiation, and activation of neutrophilic granulocyte lineage cells. It also enhances M-CSF induced monocyte differentiation and the proliferation of Th2-inducing dendritic cells. G-CSF promotes the development of T cell immune tolerance as well as tissue recovery following myocardial infarction and cerebral ischemia. It signals through G-CSF R/CD114 on monocytes, neutrophils, megakaryocytes, platelets, myeloid progenitors, trophoblasts and placenta, endothelial cells, and various tumor cell types. Mutations in G-CSF R are associated with congenital neutropenia.