RRV latent infection of BJAB cells protects the cells from apoptosis.

<p>A. RRV latent infection of BJAB cells protects the cells against apoptosis and inhibition of autophagy abolishes the protective effect. BJAB cells latently infected with RRV (BJAB-RRV) were either untreated, treated with 3-MA for 3 h prior apoptosis induction by TNF-α and cycloheximide, or treated with ammonium chloride at the same time of the apoptosis induction. The cells were harvested 2 h post-apoptosis induction for Western blotting of PARP-1 cleavage. Similar treatment of uninfected BJAB cells was included as a control. The ratio of top PARP-1 band to low band is shown under the image. B. Detection of vFLIP in RRV-infected BJAB cells by Western blotting with rabbit anti-vFLIP antibody. C. Cell viability assay of BJAB and BJAB-RRV cells 3 h after apoptosis induction. Relative folds in comparison with uninfected BJAB cells at 0 h are shown. Significant differences between BJAB and BJAB-RRV cells after apoptosis induction are denoted by “**", which indicates <i>P</i><0.01. D. Suppression vFLIP expression in RRV-infected BJAB cells by siRNA. BJAB cells latently infected with RRV were transfected with a siRNA against vFLIP. An irrelevant siRNA was included as a control. Real-time RT-PCR was conducted to assess vFLIP transcript level. Relative percentages in comparison with mock-treated control are shown. Significant differences between siRNA-treated and mock-treated BJAB-RRV cells are denoted by “**". E. Suppression of RRV vFLIP gene expression in BJAB-RRV cells leads to loss of the capability against apoptosis. BJAB cells latently infected with RRV were transfected with siRNA against vFLIP 15 h before apoptosis induction. Treatment of uninfected BJAB cells was included as a control. The cells were harvested 2 h after treatment with TNF-α and cycloheximide for Western blotting of PARP-1 cleavage. The ratios of top PARP-1 band to low band are shown under the image.