Notably, our results showed that without IFN-γ treatment, the IE1 mRNA expression and viral titer in HFF cells were not significantly different between HCMV-Towne and HCMV-Towne-ΔUL23 (Figure 4C,D), which may be due to the low expression levels of these three proteins in the host during HCMV infection, which cannot effectively suppress the replication of HCMV. This evidence concerns the gene IFNG and cytomegalovirus infection.