IFNB1 and viral infectious disease: To study if the Us3 deletion virus infections induced further production of type I IFNs, the IFN-α and IFN-β mRNA expression levels were studied with quantitative real-time PCR at 5 h and 24 h p.i. The d120 infection significantly increased the IFN-β mRNA expression when compared to its parental virus HSV-1 (KOS)-infected cells at 5 h and 24 h p.i. (5 moi, P = 0.017 and 5 moi, P = 0.024, respectively) (Figure 4A).