Figure 9.

Entamoeba histolytica does not induce Reactive Oxygen Species (ROS) formation. (A) Human neutrophils (PMN) were previously incubated with the ROS-sensitive fluorescent compound DCFDA (15 μM), and were not stimulated (—), or were stimulated with 20 nM phorbol 12-myristate 13-acetate (PMA), or with 200 μM tert-butyl hydrogen peroxide (TBHP), or with E. histolytica trophozoites. Fluorescence was read in a plate-reader for 2 h at 36°C. Data are mean ± SEM of relative fluoresce units (RFU) from three experiments. (B) Neutrophils (PMN) or E. histolytica trophozoites were treated with solvent alone (black symbols) or with the NADPH-oxidase inhibitor diphenyleneiodonium (DPI) (10 μM) (white symbols). Cell viability was estimated by Trypan Blue exclusion every 15 min.