Chang Kyeong-Ok, George David W
Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA.
J Virol. 2007 Nov;81(22):12111-8. doi: 10.1128/JVI.00560-07. Epub 2007 Sep 12.
The development of effective therapies for noroviral gastroenteritis has been hampered by the absence of a cell culture system. Recently, we reported the generation of Norwalk virus (NV) replicon-bearing cells in BHK21 and Huh-7 cells and demonstrated that alpha interferon (IFN-alpha) effectively inhibited the replication of NV in these cells. In continuing studies for screening potential antinoroviral agents, we tested IFN-gamma and ribavirin for their effects on NV replication in the cells. Like IFN-alpha, IFN-gamma inhibited the replication of NV in the replicon-bearing cells, showing the reduction of the NV genome and proteins in a dose-dependent manner. The effective dose for reducing 50% (ED(50)) of the NV genome and protein was calculated to be approximately 40 units/ml. When ribavirin was applied to the cells, it effectively reduced the NV genome and protein with the ED(50) calculated as approximately 40 microM. The combination of IFN-alpha and ribavirin showed additive effects on the inhibition of NV replication. With the addition of guanosine to the ribavirin treatment, moderately reversed antiviral effects were observed, suggesting that the ribavirin effect may be associated with the depletion of GTP in the cells. Sequencing analysis of the conserved polymerase regions of NV in the ribavirin-treated (100 microM) and nontreated groups showed that the mutation rates were similar and indicated that ribavirin did not induce catastrophic mutations. The NV replicon-bearing cells provide an excellent tool for screening potential antinoroviral agents, and our results indicated that IFNs and ribavirin may be good therapeutic options for noroviral gastroenteritis.
由于缺乏细胞培养系统，诺如病毒胃肠炎有效治疗方法的研发受到了阻碍。最近，我们报道了在BHK21细胞和Huh-7细胞中产生携带诺沃克病毒（NV）复制子的细胞，并证明α干扰素（IFN-α）能有效抑制NV在这些细胞中的复制。在继续筛选潜在抗诺如病毒药物的研究中，我们测试了IFN-γ和利巴韦林对细胞中NV复制的影响。与IFN-α一样，IFN-γ抑制了携带复制子细胞中NV的复制，呈剂量依赖性地减少了NV基因组和蛋白质。使NV基因组和蛋白质减少50%的有效剂量（ED50）计算约为40单位/毫升。当将利巴韦林应用于细胞时，它能有效减少NV基因组和蛋白质，ED50计算约为40微摩尔。IFN-α和利巴韦林联合使用对抑制NV复制显示出相加作用。在利巴韦林治疗中添加鸟苷后，观察到抗病毒作用有适度逆转，这表明利巴韦林的作用可能与细胞中GTP的消耗有关。对利巴韦林处理组（100微摩尔）和未处理组中NV保守聚合酶区域的测序分析表明，突变率相似，这表明利巴韦林不会诱导灾难性突变。携带NV复制子的细胞为筛选潜在抗诺如病毒药物提供了一个极好的工具，我们的结果表明，IFN和利巴韦林可能是诺如病毒胃肠炎的良好治疗选择。
