Endogenous shRNA in transgenic cell lines provided an inhibitory effect to serotype Asia 1 FMDV infection. Three cell lines, IB-3D2B-2, IB-3D2B-3, and IB-3D2B-6, were challenged with 20 TCID50 of FMDV Asia 1/Jiangsu/2005. Supernatant virus titers (A) and the relative titer reduction (B) 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.