Figure 5

Endogenous shRNA in transgenic cell lines conferred natural resistance to serotype O FMDV infection. Eight cell lines and control cells were challenged with 20 TCID₅₀ of FMDV O/HKN/2002. Culture supernatants were collected at 24, 48 and 72 hpc, and virus yields were measured by TCID₅₀ (A). Three of the cell lines with an obvious antiviral ability were further challenged with a higher dose of 50 TCID₅₀ of serotype O virus. Supernatant virus titers (B) and the relative titer reduction (C) were measured. The data represent the means ± SEM of three separate experiments. Asterisks indicate the samples that are different from normal IBRS-2 cells at the same time interval as determined by two-way ANOVA with Bonferroni post-test, *P < 0.05, ***P < 0.001.