PEDV infection results in Apparent Apoptosis in Vero, Vero-E6 and MARC145 cells. Mock and infected Vero, Vero-E6 and MARC145 cells were collected and stained with 7-AAD and annexin-V-PE at 48 h post infection, and then analyzed by flow cytometry. (a) PEDV SM98 and CV777 strains both could induce significant apoptosis in Vero-E6, Vero and MARC-145 cells. (b, d, f) Percentages of annexin-V-PE positive cells from SM98 and CV777 infected Vero-E6, Vero and Marc-145 cells. (c, e, g) Percentages of annexin-V-PE positive and 7AAD negative cells from SM98 and CV777 infected Vero-E6, Vero and Marc-145 cells. Results are representative of three independent experiments. Data are represented as mean ± SD, n = 3. (**, p < 0.01; ***, p < 0.001;ns, no significant).