GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR (GM-CSF) REDUCES TOXOPLASMASTATIC ACTIVITY OF HUMAN MONOCYTES VIA INDUCTION OF PROSTAGLANDIN E(2) (PGE(2))

In this study we investigated the effect of human GM-CSF on the toxopl asmastatic activity and release of H2O2 and PGE(2) by human monocytes. Incubation of monocytes from healthy controls with GM-CSF resulted in a dose-dependent reduction of toxoplasmastatic activity and a decreas e in H2O2 production. Furthermore GM-CSF-treated monocytes released mo re PGE(2) than untreated cells. To investigate the role of PGE(2) in t he reduced toxoplasmastatic activity of GM-CSF-treated monocytes, thes e cells were incubated with indomethacin. This resulted in a reduction of PGE(2) release and restoration of toxoplasmastatic activity of mon ocytes treated with GM-CSF. GM-CSF reduces the toxoplasmastatic activi ty of monocytes via production of PGE(2).