The effect of tunicamycin and monensin on the association of Trypanosoma cruzi with resident macrophages.

The effect of incubation of parasites (epimastigote and trypomastigote forms of Trypanosoma cruzi) or macrophages in the presence of tunicamycin (TM) or monensin (M) on the parasite-macrophage association was analysed. Treatment of the parasites with TM, a drug which interferes with the process of N-glycosylation of proteins, increased by about 70% and decreased by about 27% the infection of epimastigote and trypomastigote forms, respectively. Treatment of the macrophages with TM increased by about 65% and reduced by about 45% the ingestion of epimastigote and trypomastigote forms, respectively. Treatment of the parasites or the macrophages with monensin, a drug which interferes with the sorting of membrane proteins, significantly reduced the ingestion of epimastigote and trypomastigote forms by the macrophages. The effects of both drugs were reversible. Treatment of the macrophages with trypsin followed by their incubation in fresh medium containing tunicamycin or monensin was used to analyse further the effects of these two drugs on the macrophages. The effects of the drugs on macrophages and parasites were controlled by electron microscopy. The results obtained suggest that the N-glycosylated proteins exposed on the surface of both cells are involved in the process of parasite-macrophage interaction and that interference in the process of sorting of membrane components alters the interaction.