| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 2511136 | Antiviral Research | 2008 | 8 Pages |
Background/AimInterferon-gamma (IFN-γ) produced by activated T-cells is the principle mediator of non-cytolytic Hepatitis B virus (HBV) inactivation; however the intracellular pathways responsible are poorly defined. We investigated the role of IFN-γ–inducible nitric oxide synthase (iNOS) and APOBEC3 (A3) enzyme family in the inhibition of HBV replication by IFN-γ.MethodsHepatoma-cell lines transfected with HBV DNA were treated with IFN-γ. Viral replication, iNOS and A3 mRNAs were quantitated by TaqMan®PCR and the direct nitric oxide (NO) effect on HBV replication was investigated using an NO-donor. A3G antiviral activity was verified by co-transfection with its inhibitor, human immunodeficiency virus (HIV)-associated virion infectivity factor (Vif).ResultsIFN-γ caused a dose-dependent reduction (>50%) of HBV DNA in the absence of cytotoxicity. Although iNOS mRNA increased 45-fold in IFN-γ treated cells, NO2− was not detectable in supernatants and the use of an NO-donor did not inhibit HBV replication. A3 enzyme mRNAs varied between cells and were >10-fold higher in lymphocytes than in liver tissue. IFN-γ up-regulated A3G mRNA by three-fold, associated with significant HBV DNA decrease. However, A3G degradation by Vif did not abolish the antiviral effect of IFN-γ against HBV.ConclusionsIFN-γ inhibits HBV replication and up-regulates both iNOS and A3G. However, other pathways appear to have a greater role in IFN-γ-induced HBV inactivation in the liver.
