Effect of HCV NS5A expression in HeLa cells on interferon sensitive virus VSV replication

    LIAO Jiª²Pei, XUE Xiaoª²Ping, YIN Wen, LEI Yingª²Feng, L¦a Xin, YANG Jing, XU Zhiª²Kai

    Department of Microbiology, School of Basic Medicine, Fourth Military Medical University, Xi¬ðan 710033£¬China

    ¡¾Abstract¡¿ AIM: To demonstrate the effect of HCV NS5A expression on vesicular stomatitis virus (VSV) replication. METHODS: Stably transfected cells were cultured per well in a 6ª²well tissue culture plate and cultured for 24 h. Human recombinant IFNª²¦Á2a was then added at various concentrations for 24 h to induce the IFN antiviral state. Infection with VSV was then performed and supernatants were harvested at various time points after infection. Changes in infectious virus yields were measured by a standard virus plaque assay in Vero cells. RESULTS: When the IFN concentration was 1¡Á105 U/L, HeLaª²NS5A cells infected with VSV had more obvious cytopathic effect compared with that of HeLaª²NS5Aª²¦¤ISDR cells. In the various concentration treatments of IFN, the virus titers in the supernatant of HeLaª²NS5A cells were about 2 to 5 times those of HeLaª²NS5Aª²¦¤ISDR cells (P<0.05). CONCLUSION: NS5A expression rescues VSV replication during IFN treatment and this effect is dependent on the putative interferonª²sensitivity determining region (ISDR). This effect will be helpful to demonstrate that HCV can naturally evade the IFNª²induced antiviral response in persistently infected patients. ......