Research of genetic analysis. of hepatitis C virus clones and immune response in reinfection experiment using chimpanzees.

为了研究基因相同的丙型肝炎病毒（HCV）是否可以两次再感染同一只黑猩猩，我们分析了黑猩猩模型中i - icv高变区1 （HVR1）的氨基酸序列和免疫反应。黑猩猩#63和#65接种了三次含有HCV- f株衍生的HCV的血清。每次接种后，两只黑猩猩都患上了急性丙型肝炎病毒血症，然后随着丙型肝炎病毒RNA的消失而恢复。与初次接种相关的HCV RNA消失后，两次接种之间的间隔至少为一年。克隆每次接种以及每次接种后的黑猩猩急性期血清，进行序列和氨基酸分析。检测HCV非结构区、核心区和HVR1区的抗体滴度。第一次接种的无性系可分为主要型（83%）和次要型（17%）。然而，从第二次和第三次接种以及所有接种后急性期血清中克隆的黑猩猩与主要类型基本相同。在第二次和第三次接种以及两种黑猩猩的所有急性期血清中均未检测到与第一次接种相同的少量克隆类型。在两种黑猩猩中，针对非结构区的抗体滴度在第二次接种后持续升高，而针对核心区的抗体滴度在第二次和第三次接种后持续升高。另一方面，两种黑猩猩接种前和接种后血清中抗hvr1抗体的滴度均较低。结果表明，具有相同氨基酸序列的同一株HCV克隆可以两次再感染同一只黑猩猩。即使是同一株丙型肝炎病毒，反复再感染的黑猩猩也未能产生足够的抗hvr1抗体反应，这表明丙型肝炎病毒感染免疫的复杂性。

To investigate whether the genetically same hepatitis C virus (HCV) could twice reinfect the same chimpanzee or not, we analyzed amino acid sequences of hypervariable region 1 (HVR1) of I-IC V and immune response in a chimpanzee model. Chimpanzees #63 and #65 were inoculated, three times, with sera containing HCV derived from HCV-F strain. After each inoculation, both chimpanzees 4eveloped acute hepatitis C with viremia, then recovered, with the disappearance of HCV RNA. The interval between subsequent inoculations was at least one year after the disappearance of HCV RNA associated with the initial inoculation. Cloning using each inocula as well as each post inoculation acute phase sera of the chimpanzees, sequence and amino acid analysis were performed. Antibody titers against HCV non-structure, core and HVR1 regions were measured. Clones from the first inocula could be divided into major (83%) and minor (17%) types. Whereas, clones from the second and the third inocula as well as all post inoculation acute phase sera from both chimpanzees were mostly identical to the major type. Minor types of clone as same as in the first inocula were not detected in the second and the third inocula as well as all acute phase sera from both chimpanzees. In both chimpanzees, titers of antibody against the non-structure region were elevated post-2nd inoculation and were continuous, and those against the core region were elevated post-2nd and 3rd inoculations. On the other hand, titers of anti-HVR1 antibody showed a low titer in pre-and post-inoculation sera from both chimpanzees. The results showed that clones of the same strain of HCV with identical amino acid sequence could twice reinfect the same chimpanzee. The failure in developing an adequate anti-HVR1 antibody response in the chimpanzees with repeatedly reinfection even with the same strain of HCV indicated the complexity of HCV infection immunity.