G-CSF: function and modes of action (Review).

Since the observations in the 1960s that granulocyte-colony stimulating factor (G-CSF) stimulated the proliferation of granulocytic cells in semisolid cultures of bone marrow cells, G-CSF has established itself as a useful clinical agent for increasing levels of neutrophilic granulocytes. However, these early findings did not firmly establish whether G-CSF is a genuine regulator of granulocyte formation under normal physiological conditions or rather acts as an emergency regulator, playing an important role only under stress conditions. The advent of <gene-knockout technology> has allowed us to evaluate these questions in a physiological setting through analysis of mice with a targeted mutation of G-CSF or its receptor, while the development of relevant cell models has enabled us to dissect the molecular basis of G-CSF action. This review discusses our current state of knowledge regarding the role of G-CSF in granulopoiesis.