Granulocyte-macrophage colony-stimulating factor restricts growth of tubercle bacilli in human macrophages

The effect of human recombinant granulocyte-macrophage colony stimulating factor (GM-CSF) on the uptake and intracellular growth of Mycobacterium tuberculosis in human macrophages was investigated. GM-CSF was found to reduce growth of M. tuberculosis in human monocyte-derived macrophages in vitro, as compared to untreated cells. The decrease in intracellular growth of the tubercle bacilli did not depend on generation of reactive oxygen species, inasmuch as treatment with scavengers did not affect the ability of GM-CSF to restrict mycobacterial growth in macrophages.