Interferon regulatory factors IRF-3 and IRF-7 are central to the
establishment of the innate antiviral response. This study examines HSV-1
pathogenesis in IRF-3−/−,
IRF-7−/− and double-deleted
IRF3/7−/− (DKO) mice. Bioluminescence imaging of
infection revealed that DKO mice developed visceral infection following corneal
inoculation, along with increased viral burdens in all tissues relative to
single knockout mice. While all DKO mice synchronously reached endpoint criteria
5 days post infection, the IRF-7−/− mice survived
longer, indicating that although IRF-7 is dominant, IRF-3 also plays a role in
controlling disease. Higher levels of systemic proinflammatory cytokines were
found in IRF7−/− and DKO mice relative to wild-type
and IRF-3−/− mice, and IL-6 and G-CSF, indicative of
sepsis, were increased in the DKO mice relative to wild-type or single-knockout
mice. In addition to controlling viral replication, IRF-3 and −7
therefore play coordinating roles in modulation of inflammation during HSV
infection.