FIG 2.

MEV infection induced apoptosis in F81 cells. (A) The cell viability of MEV infected cells was compared to control at different time points postinfection. F81 cells were infected with MEVB at 0.5 MOI and harvested at 12, 24, 36, 48, 60, and 72 h. Cell viability was measured by MTT assay. (B) MEV infection led F81 cells to be arrested at G₁ phase. The DNA contents of F81 cells mock infected or infected with MEVB at an MOI of 0.5 were collected at 24, 48, and 72 h postinfection (hpi), and the cell cycle was analyzed by PI staining and flow cytometry. (C) Apoptosis determination. Cells infected with MEVB at an MOI of 0.5 were stained with annexin V-FITC and PI at different time points postinfection and were analyzed by flow cytometry. Annexin V-positive cells were regarded as apoptotic. Data are means ± SEMs from three independent experiments. *, P < 0.05, and **, P < 0.01, compared with control groups.