IFNG and infection: The transcription level of IFN-γ secreted by local infected tissue, a critical immune regulator that exerts antiviral effects, was five times higher in tissues from HVEM−/− mice than in those from C57BL/6 mice 48 h after infection, and the transcription level of IFN-α, a key indicator of innate immunity activation, was three times higher in HVEM−/− mice than in C57BL/6 mice and stayed at a higher level in HVEM−/− mice for a period of time (Figure 3A).