The results showed (Figure 5A–D) that at the late stage of Marc-145 infection with PRRSV, the PRRSV-infected group down-regulated the expression of RIG-I, MAVS, TBK1, and IRF3 mRNA levels compared with the cells of the uninfected group, and the different concentrations of naringenin-treated groups all up-regulated the expression of their mRNAs to a certain extent. This evidence concerns the gene TBK1 and infection.