BACKGROUND/AIM Interferon-gamma (IFN-gamma) 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-gamma-inducible nitric oxide synthase (iNOS) and APOBEC3 (A3) enzyme family in the inhibition of HBV replication by IFN-gamma. METHODS Hepatoma-cell lines transfected with HBV DNA were treated with IFN-gamma. Viral replication, iNOS and A3 mRNAs were quantitated by TaqManPCR 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). RESULTS IFN-gamma caused a dose-dependent reduction (>50%) of HBV DNA in the absence of cytotoxicity. Although iNOS mRNA increased 45-fold in IFN-gamma 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-gamma 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-gamma against HBV. CONCLUSIONS IFN-gamma inhibits HBV replication and up-regulates both iNOS and A3G. However, other pathways appear to have a greater role in IFN-gamma-induced HBV inactivation in the liver.

中文翻译：

---

APOBEC 和 iNOS 不是 IFN-γ 介导的乙型肝炎病毒复制失活的主要细胞内效应器。


背景/目的 由活化的 T 细胞产生的干扰素-γ (IFN-γ) 是非溶细胞性乙型肝炎病毒 (HBV) 失活的主要介质；然而，负责的细胞内途径尚不清楚。我们研究了 IFN-γ 诱导型一氧化氮合酶 (iNOS) 和 APOBEC3 (A3) 酶家族在 IFN-γ 抑制 HBV 复制中的作用。方法 用 IFN-γ 处理转染 HBV DNA 的肝癌细胞系。通过 TaqManPCR 定量病毒复制、iNOS 和 A3 mRNA，并使用 NO 供体研究一氧化氮 (NO) 对 HBV 复制的直接影响。 A3G 的抗病毒活性通过与其抑制剂、人类免疫缺陷病毒 (HIV) 相关病毒粒子感染因子 (Vif) 共转染得到验证。结果 IFN-γ 在没有细胞毒性的情况下引起 HBV DNA 剂量依赖性减少 (>50%)。尽管 iNOS mRNA 在 IFN-γ 处理的细胞中增加了 45 倍，但在上清液中未检测到 NO2-，并且使用 NO 供体并不能抑制 HBV 复制。 A3 酶 mRNA 在细胞之间存在差异，淋巴细胞中的 A3 酶 mRNA 比肝组织中高 10 倍以上。 IFN-γ 将 A3G mRNA 上调三倍，与 HBV DNA 显着减少相关。然而，Vif 降解 A3G 并没有消除 IFN-γ 对 HBV 的抗病毒作用。结论 IFN-γ 抑制 HBV 复制并上调 iNOS 和 A3G。然而，其他途径似乎在 IFN-γ 诱导的肝脏 HBV 灭活中发挥着更大的作用。