Fig. 8. Dose effect of Lbpro on MDA5-dependent IFN-β induction.

HEK293 cells (1 × 10⁶) were co-transfected with 50 ng of pIFN-β-FL, 25 ng of pRL-TK, and 10 ng of DDK-MDA5 or DDK-MDA5TM and increasing amounts of LbWT plasmid (0.2, 2 and 20 ng). Cells were also co-transfected with an EV or LbWT plasmid (20 ng) as controls. After 24 h, cells were mock-treated or stimulated with FMDV IRES RNA transcripts. Cells were harvested 24 h later and IFN-β induction was measured by dual-luciferase assay detecting expression of firefly luciferase under the human IFN-β promoter normalized to renilla activity. Data are average of duplicates of two independent assays ± SD. Significant differences using the Student´s t test are indicated with comparisons made to RNA-treated MDA5 or MDA5TM cells (LbWT-) (*p < 0.05; **p < 0.01).