Orii K, Tanaka E, Rokuhara A, Maruyama A, Ichijo T, Yoshizawa K, Kiyosawa K
Second Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
Intervirology. 2000;43(3):139-45. doi: 10.1159/000025039.
Changes in the deduced amino acid sequence of the envelope 2 (E2) region of the GB virus C/hepatitis G virus (GBV-C/HGV) were analyzed to investigate whether or not the region contributes to persistent infection with the virus.
Eight patients with acute hepatitis C and 1 patient with acute hepatitis of unknown etiology were included in the study. GBV-C/HGV RNA was detected in 6 patients, including the patient with hepatitis of unknown origin. The nucleotide sequence of the E2 region of hepatitis C virus (HCV) and GBV-C/HGV was determined by direct sequencing of polymerase chain reaction products in 5 patients with HCV infection and in 6 patients with GBV-C/HGV infection twice during the period of early infection and several months or years later in each patient.
The mean substitution rate of the deduced amino acid sequence in the E2 region was over 100 times lower (p < 0.001) in GBV-C/HGV (0.01 +/- 0.04/month/100 sites) than in HCV (2.4 +/- 1.7/month/100 sites). The amino acid sequence of the loop domain of GBV-C/HGV-E2 did not change in any of the 6 patients. On the other hand, the sequence of the hypervariable region of HCV-E2 changed remarkably (5.9 +/- 4.3/month/100 sites). No amino acid substitution in the loop domain was observed in 7 additional patients who showed persistent GBV-C/HGV viremia for more than 2 years.
These results indicate that changes in the amino acid sequence of the E2 region are not involved in the mechanism of persistent GBV-C/HGV infection.
分析GB病毒C/庚型肝炎病毒（GBV-C/HGV）包膜2（E2）区推导的氨基酸序列变化，以研究该区域是否与病毒的持续感染有关。
本研究纳入8例急性丙型肝炎患者和1例病因不明的急性肝炎患者。6例患者检测到GBV-C/HGV RNA，包括病因不明的肝炎患者。通过对5例丙型肝炎病毒（HCV）感染患者和6例GBV-C/HGV感染患者的聚合酶链反应产物进行直接测序，在早期感染期间及之后的数月或数年，分别对每位患者的HCV和GBV-C/HGV的E2区核苷酸序列进行测定。
GBV-C/HGV的E2区推导氨基酸序列的平均替换率（0.01±0.04/月/100个位点）比HCV（2.4±1.7/月/100个位点）低100倍以上（p<0.001）。6例患者中GBV-C/HGV-E2环结构域的氨基酸序列均未发生变化。另一方面，HCV-E2高变区的序列变化显著（5.9±4.3/月/100个位点）。另外7例GBV-C/HGV病毒血症持续超过2年的患者，其环结构域未观察到氨基酸替换。
这些结果表明，E2区氨基酸序列的变化与GBV-C/HGV持续感染的机制无关。
