In an FMDV-based IFN biological assay, IFN production was significantly higher in the IFNAR-KO cells than in the WT cells at 3–5 days post baculovirus inoculation, and the highest units/mL of IFN was obtained in the IFNAR-KO cells at 4 days post infection (p < 0.05, Figure 4D). The gene discussed is IFNA1; the disease is infection.