Kato T, Mizokami M, Nakano T, Orito E, Ohba K, Kondo Y, Tanaka Y, Ueda R, Mukaide M, Fujita K, Yasuda K, Iino S
Second Department of Medicine, Nagoya City University Medical School, Mizuho, Nagoya, Japan.
J Med Virol. 1998 Jun;55(2):109-17.
GB virus C/hepatitis G virus (GBV-C/HGV) is related distantly to hepatitis C virus (HCV). HCV has a hypervariable region (HVR), and exists as quasispecies in vivo. Although GBV-C/HGV also has replaceable amino acids in the presumed antigenic region, the existence and fluctuation of population of heterogeneous virus have not been evaluated. In this study, the heterogeneity of GBV-C/HGV and HCV was investigated by the single-strand conformation polymorphism (SSCP) analysis in six concomitantly infected patients. Two patients were observed for 4 years without any treatment, and four were treated with interferon-alpha (IFN). By SSCP analysis, amplicons of GBV-C/HGV RNA were separated into 1-5 bands on gels for each patient. The amplicons had different nucleotide but the same amino acid sequences in the presumed antigenic region. The amplicons of HCV RNA, separated into 1-4 bands, had different nucleotide and amino acid sequences in the HVR. In the two patients without treatment, the predominant strain of GBV-C/HGV was unchanged for the 4 years. In the four patients administered IFN, some strains of GBV-C/HGV disappeared after IFN therapy, whereas other strains persisted. The mean genetic distance among GBV-C/HGV strains represented by SSCP analysis was significantly lower than that of HCV (P < 0.05). The data indicate that: 1) GBV-C/HGV can be devoid of antigenic drift unlike HCV; 2) GBV-C/HGV has no HVR as seen in HCV in the presumed antigenic region; and 3) the sensitivity to IFN differs among GBV-C/HGV strains in the same hosts, as with HCV.
庚型肝炎病毒（GBV-C/HGV）与丙型肝炎病毒（HCV）的亲缘关系较远。HCV有一个高变区（HVR），在体内以准种形式存在。虽然GBV-C/HGV在推测的抗原区域也有可替换的氨基酸，但尚未评估异质病毒群体的存在和波动情况。在本研究中，通过单链构象多态性（SSCP）分析，对6例合并感染的患者进行了GBV-C/HGV和HCV异质性研究。2例患者未经治疗观察了4年，4例接受了α干扰素（IFN）治疗。通过SSCP分析，GBV-C/HGV RNA扩增子在凝胶上为每位患者分离出1-5条带。这些扩增子在推测的抗原区域具有不同的核苷酸序列，但氨基酸序列相同。HCV RNA扩增子分离为1-4条带，在HVR中具有不同的核苷酸和氨基酸序列。在2例未经治疗的患者中，GBV-C/HGV的优势毒株在4年中未发生变化。在4例接受IFN治疗的患者中，一些GBV-C/HGV毒株在IFN治疗后消失，而其他毒株持续存在。通过SSCP分析表示的GBV-C/HGV毒株之间的平均遗传距离显著低于HCV（P<0.05）。数据表明：1）与HCV不同，GBV-C/HGV可能不存在抗原漂移；2）GBV-C/HGV在推测的抗原区域没有HCV那样的HVR；3）与HCV一样，同一宿主中GBV-C/HGV毒株对IFN的敏感性也有所不同。
