Study on infection and maturation mechanisms of hepatitis C virus and its host response.

为了研究丙型肝炎病毒（HCV）感染的分子机制，我们在293T和CHO细胞中制备了基于水泡性口炎病毒（HCVpv）的携带未修饰的HCV包膜蛋白的假病毒。293T细胞中产生的HCVpv （HCVpv/293T）对Huh7细胞具有较高的感染性，但对HepG2细胞没有感染性。HCVpv/293T对Huh7细胞的感染被抗hcd81抗体所中和，报道了在293T细胞中产生的基于小鼠白血病病毒（HCVpp）的伪病毒。相反，CHO细胞中生成的HCVpv （HCVpv/CHO）对hcd81阴性的HepG2细胞具有较高的感染性，对Huh7细胞的感染性较弱。这些结果表明，HCVpv/293T和HCVpv/CHO分别表现出hcd81依赖性和非依赖性的感染性。慢性丙型肝炎患者的血清有效地中和了HCVpv/293T感染，正如HCVpp感染所报道的那样，而仅观察到对HCVpv/CHO感染的轻微抑制。在感染窗口期从丙型肝炎患者血清中提取的自然存在的HCV颗粒也显示出与Huh7和HepG2细胞的结合。综上所述，这些结果表明，HCV假病毒的细胞趋向性是由产生的细胞系决定的，并且至少有两种与hcd81依赖性和非依赖性假病毒具有相似特性的HCV颗粒在丙型肝炎患者的血清中循环。

To examine the molecular mechanisms of hepatitis C virus (HCV) infection, we prepared pseudotype viruses bearing unmodified HCV envelope proteins based on vesicular stomatitis virus (HCVpv) in both 293T and CHO cells. HCVpv generated in 293T cells (HCVpv/293T) exhibited a high infectivity to Huh7 cells but not to HepG2 cells. The infection of HCVpv/293T to Huh7 cells was neutralized by anti-hCD81 antibody, as reported for the pseudotype viruses based on murine leukemia virus (HCVpp) generated in 293T cells. In contrast, HCVpv generated in CHO cells (HCVpv/CHO) exhibited a high infectivity to hCD81-negative HepG2 cells and a weak infectivity to Huh7 cells. These results indicate that HCVpv/293T and HCVpv/CHO exhibit hCD81-dependent and -independent infectivity, respectively. Sera taken from chronic hepatitis C patients efficiently neutralized HCVpv/293T infection, as reported for HCVpp infection, whereas only a slight inhibition of HCVpv/CHO infection was observed. Naturally occurring HCV particles in serum taken from a hepatitis C patient during the window period of infection also exhibited binding to both Huh7 and HepG2 cells. In conclusion, these results indicate that the cell tropism of the HCV pseudotype viruses is determined by the producing cell lines, and that at least two types of HCV particles bearing similar properties to the pseudotype viruses exhibiting hCD81-dependent and -independent infection circulate in the serum of hepatitis C patients.