Bone marrow-derived macrophages grown in GM-CSF or NI-CSF differ in their ability to produce IL-12 and to induce IFN-γ production after stimulation with Trypanosoma cruzi antigens

Trypanosoma cruzi is the etiological agent of Chagas' disease in man. Control of parasitism at the beginning of experimental infection depends on cytokine-activated macrophages that synthesize nitric oxide (NO). We investigated macrophage populations derived in the presence of M-CSF (M-MM) or GM-CSF (GM-M empty set) regarding their ability to control intracellular parasitism by T. cruzi and to synthesize IL-12 and NO. Both macrophage populations supported intracellular multiplication of the parasite; when activated by IFN-gamma, GM-M empty set exerted better control of parasitism. Stimulation of GM-M empty set with T. cruzi or Staphylococcus aureus resulted in IL-12 production and higher levels of NO synthesis in comparison with stimulated M-M empty set. Mice immunized with parasite-Ag-pulsed GM-M empty set but not with pulsed M-MO had increased IFN-gamma and IL-2 production in lymph nodes. However, when immunization was followed by infection with live parasites, transient elevation of IFN-gamma production was observed in both GM-M empty set- and M-M empty set-immunized mice, without reduction of blood parasite levels. (C) 2001 Elsevier Science B.V. All rights reserved.