Divergent activities of interferon-alpha subtypes against intracellular hepatitis C virus replication

Backgrounds: Interferon (IFN)-alpha is represented by several structurally related subtypes that show different antiviral and anti-tumor effects. Here, we analyzed differential effects of IFN-alpha subtypes on intracellular hepatitis C virus (HCV) replication using HCV subgenomic replicon system as a model.Methods: Huh7 and HeLa cells supporting expression of HCV replicon were treated with various concentrations of five recombinant human IFN-alpha subtypes 1, 2, 5, 8, and 10, and with IFN-alpha con I. The effects of IFNs on various cell-signaling pathways were assayed by using ISRE-, GAS-, AP1-, NF-kappa B-, CRE-, and SRE-luciferase reporter plasmids.Results: Each IFN-alpha subtype suppressed HCV replication in a dose-dependent manner. Among them, IFN-alpha8 was the most effective, while IFN-alpha1 was the least effective with 50% inhibitory concentrations of 0.123 IU/ml versus 0.375 IU/ml, respectively. These differential effects against HCV replication did not correlate with levels of the IFN-responsive ISRE or GAS reporter activities, nor they did activate the other reporters, AP1, NF-kappa B, CRE and SRE.Conclusion: There were divergent effects of IFN-alpha subtypes against HCV replication that may be through JAK-STAT-independent pathways. Exploring further mechanisms of action may elucidate IFN-mediated cellular antiviral mechanisms. (c) 2005 Elsevier Ireland Ltd. All rights reserved.

背景：干扰素（IFN）-α由几种结构相关的亚型组成，它们表现出不同的抗病毒和抗肿瘤效应。在此，我们以丙型肝炎病毒（HCV）亚基因组复制子系统为模型，分析了IFN-α亚型对细胞内HCV复制的不同作用。 方法：用不同浓度的5种重组人IFN-α亚型（1、2、5、8和10）以及IFN-α con I处理支持HCV复制子表达的Huh7细胞和HeLa细胞。通过使用ISRE -、GAS -、AP1 -、NF -κB -、CRE -和SRE -荧光素酶报告质粒来检测干扰素对各种细胞信号通路的影响。 结果：每种IFN -α亚型都以剂量依赖的方式抑制HCV复制。其中，IFN -α8最有效，而IFN -α1效果最差，其50%抑制浓度分别为0.123 IU/ml和0.375 IU/ml。这些针对HCV复制的不同效应与干扰素应答性的ISRE或GAS报告基因活性水平无关，也未激活其他报告基因（AP1、NF -κB、CRE和SRE）。 结论：IFN -α亚型对HCV复制有不同的作用，可能是通过JAK - STAT非依赖途径。进一步探索作用机制可能阐明干扰素介导的细胞抗病毒机制。（c）2005 Elsevier Ireland Ltd.保留所有权利。