Sarrazin C, Bruckner M, Herrmann E, Rüster B, Bruch K, Roth W K, Zeuzem S
Medizinische Klinik II, J.W. Goethe-Universität, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
Virology. 2001 Oct 10;289(1):150-63. doi: 10.1006/viro.2001.1092.
Two regions within the HCV genome, hypervariable region 1 (HVR1) within the envelope (E)2 region and the PKR-binding domain (PKRbD) comprising the interferon sensitivity determining region (ISDR) within the nonstructural (NS)5A protein, have been reported to correlate with the outcome of antiviral treatment. Recently, a PKR/eIF2alpha phosphorylation homology domain (PePHD) within the E2 protein of HCV-1 isolates was described to inhibit PKR in vitro. PePHD deleted HCV-1 mutants remain capable of binding PKR to some extent while inhibition of PKR was found to be abolished by carboxy-terminal truncated E2 protein. The importance of mutations and quasispecies heterogeneity within the carboxy-terminal part of the E2 protein comprising the PePHD of HCV-1b is unknown. Therefore, the carboxy-terminal part of the HCV E2 gene (codons 618-746) including the PePHD was analyzed by sequencing of PCR products and individual clones of 41 HCV-1b-infected patients with sustained (SR, n = 12), end-of-treatment (ETR, n = 10), or no virological (NR, n = 19) response to antiviral therapy. Two highly conserved regions (codons 658-673 comprising the PePHD and codons 675-704) and one variable region (codons 705-720) were detected within the carboxy-terminal part of E2. No significant correlation of specific mutations or number of mutations with treatment response was observed for the PePHD and the carboxy-terminal part of the E2 protein. Phylogenetic and conformational analyses showed no specific clusters related to treatment outcome. Calculation of genetic complexity and diversity based on nucleotide sequence analyses of 20 individual clones per patient showed no differences between matched SR, ETR, and NR patients. However, calculation of genetic complexity and diversity on the basis of amino acid sequences showed significantly lower normalized Shannon entropy as well as mean Hamming distances for SR patients than in ETR and NR patients (P = 0.029 and P = 0.027, respectively). This indicates that patients achieving a sustained virological response to interferon-alpha-based antiviral therapy may elicit more effective immunological pressure, resulting in continuous clearing of individual variants of HCV quasispecies.
据报道，丙型肝炎病毒（HCV）基因组内的两个区域，即包膜（E）2区域内的高变区1（HVR1）和非结构（NS）5A蛋白内包含干扰素敏感性决定区（ISDR）的PKR结合域（PKRbD），与抗病毒治疗的结果相关。最近，有人描述了HCV-1分离株E2蛋白内的一个PKR/eIF2α磷酸化同源域（PePHD）在体外可抑制PKR。缺失PePHD的HCV-1突变体在一定程度上仍能与PKR结合，而羧基末端截短的E2蛋白可消除对PKR的抑制作用。HCV-1b包含PePHD的E2蛋白羧基末端部分内的突变和准种异质性的重要性尚不清楚。因此，通过对41例接受抗病毒治疗后获得持续（SR，n = 12）、治疗结束时（ETR，n = 10）或无病毒学（NR，n = 19）应答的HCV-1b感染患者的PCR产物和单个克隆进行测序，分析了HCV E2基因的羧基末端部分（密码子618 - 746），包括PePHD。在E2的羧基末端部分检测到两个高度保守区域（包含PePHD的密码子658 - 673和密码子675 - 704）和一个可变区域（密码子7C5 - 720）。未观察到PePHD和E2蛋白羧基末端部分的特定突变或突变数量与治疗应答之间存在显著相关性。系统发育和构象分析显示，没有与治疗结果相关的特定聚类。基于每位患者20个单个克隆的核苷酸序列分析计算遗传复杂性和多样性，结果显示匹配的SR、ETR和NR患者之间没有差异。然而，基于氨基酸序列计算遗传复杂性和多样性时，SR患者的标准化香农熵以及平均汉明距离显著低于ETR和NR患者（分别为P = 0.029和P = 0.027）。这表明，对基于α干扰素的抗病毒治疗获得持续病毒学应答的患者可能引发更有效的免疫压力，从而持续清除HCV准种的各个变体。
