Oligoadenylate Synthetase/Protein Kinase R Pathways and αβ TCR+ T Cells Are Required for Adenovirus Vector: IFN-γ Inhibition of Herpes Simplex Virus-1 in Cornea

Abstract

An adenoviral (Ad) vector containing the murine IFN-γ transgene (Ad:IFN-γ) was evaluated for its capacity to inhibit HSV-1. To measure effectiveness, viral titers were analyzed in cornea and trigeminal ganglia (TG) during acute ocular HSV-1 infection. Ad:IFN-γ potently suppressed HSV-1 replication in a dose-dependent fashion, requiring IFN-γ receptor. Moreover, Ad:IFN-γ was effective when delivered −72 and −24 h before infection as well as 24 h postinfection. Associated with antiviral opposition, TG from Ad:IFN-γ-transduced mice harbored fewer T cells. Also related to T cell involvement, Ad:IFN-γ was effective but attenuated in TG from αβ TCR-deficient mice. In corneas, αβ TCR+ T cells were obligatory for protection against viral multiplication. Type I IFN involvement amid antiviral efficacy of Ad:IFN-γ was further investigated because types I and II IFN pathways have synergistic anti-HSV-1 activity. Ad:IFN-γ inhibited viral reproduction in corneas and TG from αβ IFNR-deficient (CD118−/−) mice, although viral titers were 2- to 3-fold higher in cornea and TG compared with wild-type mice. The absence of IFN-stimulated antiviral proteins, 2′-5′ oligoadenylate synthetase/RNase L, and dsRNA-dependent protein kinase R completely eliminated the antiviral effectiveness of Ad:IFN-γ. Collectively, the results demonstrate the following: 1) nonexistence of type I IFN receptor does not abolish defense of Ad:IFN-γ against HSV-1; 2) antiviral pathways oligoadenylate synthetase-RNase L and protein kinase R are mandatory; and 3) αβ TCR+ T cells are compulsory for Ad:IFN-γ effectiveness against HSV-1 in cornea but not in TG.