IFNG and cytomegalovirus infection: However, when activated Jurkat cells were co-cultured with HCMV-infected HFFs, IFN-γ production was significantly decreased in Towne-infected HFFs, while restoring IFN-γ secretion in Towne-ΔUL23-infected HFFs, indicating that UL23 mainly caused the inhibitory effect of HCMV on IFN-γ secretion of activated T cells during HCMV infection.