Figure 6. Effect of rapamycin treatment on apoptosis during murine cytomegalovirus infection. Retinal pigment epithelial (RPE) cells were infected with murine cytomegalovirus (MCMV) at low multiplicity of infection (MOI) = 1 in normal medium (A) or in medium containing rapamycin (10⁻⁶ M; C) for 2 and 3 days. B and D: Expression of cleaved caspase 3 was monitored and quantified. E: Collected cells were diluted to 1:1 using a 0.4% trypan blue solution. The stained cells and unstained cells were counted under a microscope. The calculated percentage of unstained cells represents the percentage of viable cells. Rapa: rapamycin; 2d: 2 days postinfection; 3d: 3 days postinfection. **p<0.01, ***p<0.001, ANOVA. Data are shown as mean±SEM (n=3).