Activity of C. jejuni GGT on AGS cells apoptosis. (A) 1 - Selection of the population of interest (P1) depending on the size (FSC-A) and cell density (SSC-A). The population was chosen as large as possible in order to properly select the apoptotic cells that may have varied cytological features. Fluorescence emitted at cyanine 5 wavelength (PE-Cy-5) was analyzed based on the number of events in the selected population: diploid cells are separated from hypodiploid cells (apoptotic cells). The proportion of epithelial cells in apoptosis was determined by the ratio between hypodiploid cells and the number of events in the P1 population. Typical cytometry results are shown for 2- control AGS cells, 3- AGS cells with C. jejuni GGT (10 ng/mL) and 4- AGS cells with C. jejuni GGT (10 ng/mL) preincubated with acivicin (10 μM). (B) AGS cells were cultured for 24 h with C. jejuni GGT (10 ng/mL) and preincubated or not with acivicin (10 μM). A significant difference was observed between control cells and the cells with C. jejuni GGT. However, preincubation for 2 h at 37°C with acivicin or heat inactivation (70°C, 20 min) of C. jejuni GGT had no effect. Staurosporine (10 μM) was used as the positive control. These data presented in A and B, are consistent with the results obtained during the same manipulation carried out in triplicate, representative of the results for three independent manipulations. (**indicates a significant difference, p <0.05 versus cells in PBS alone; ns for a non-significant difference, p > 0.05).