Effects of granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor on the bactericidal functions of neutrophils.

The hematopoietic growth factors granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) not only regulate the numbers of circulating neutrophils but also modulate the function of mature cells. Additionally, newly developed neutrophils subsequently released from the bone marrow in response to colony-stimulating factors (CSFs) also have enhanced function. A variety of different functions are affected, including changes in adherence, movement, phagocytosis, priming and stimulation of the respiratory burst, secretion, and degranulation. These effects also can cause increased microbicidal capacity in vitro, ex vivo, and in vivo. Both G-CSF and GM-CSF have such effects on neutrophil function, but there are differences that may result in precise modulation of the immune responses and may have implications for choice of agents for immune-based therapy for different conditions.