Department of Virology II, National Institute of Infectious Diseases, 1-23-1, Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
Department of Life Science and Medical Bioscience, Waseda University, 2-2, Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
Sci Rep. 2016 Jun 27;6:28688. doi: 10.1038/srep28688.
Directly acting antivirals recently have become available for the treatment of hepatitis C virus (HCV) infection, but there is no prophylactic vaccine for HCV. In the present study, we took advantage of the properties of Japanese encephalitis virus (JEV) to develop antigens for use in a HCV vaccine. Notably, the surface-exposed JEV envelope protein is tolerant of inserted foreign epitopes, permitting display of novel antigens. We identified 3 positions that permitted insertion of the HCV E2 neutralization epitope recognized by HCV1 antibody. JEV subviral particles (SVP) containing HCV-neutralization epitope (SVP-E2) were purified from culture supernatant by gel chromatography. Sera from mice immunized with SVP-E2 inhibited infection by JEV and by trans-complemented HCV particles (HCVtcp) derived from multi-genotypic viruses, whereas sera from mice immunized with synthetic E2 peptides did not show any neutralizing activity. Furthermore, sera from mice immunized with SVP-E2 neutralized HCVtcp with N415K escape mutation in E2. As with the SVP-E2 epitope-displaying particles, JEV SVPs with HCV E1 epitope also elicited neutralizing antibodies against HCV. Thus, this novel platform harboring foreign epitopes on the surface of the particle may facilitate the development of a bivalent vaccine against JEV and other pathogens.
直接作用抗病毒药物最近已可用于治疗丙型肝炎病毒 (HCV) 感染，但目前尚无 HCV 预防性疫苗。在本研究中，我们利用日本脑炎病毒 (JEV) 的特性开发了 HCV 疫苗抗原。值得注意的是，表面暴露的 JEV 包膜蛋白可耐受插入的外来表位，从而允许展示新的抗原。我们确定了 3 个位置，可插入 HCV1 抗体识别的 HCV E2 中和表位。通过凝胶色谱法从培养上清液中纯化了含有 HCV 中和表位的 JEV 亚病毒颗粒 (SVP-E2)。用 SVP-E2 免疫的小鼠血清可抑制 JEV 和源自多基因型病毒的转互补 HCV 颗粒 (HCVtcp) 的感染，而用合成 E2 肽免疫的小鼠血清则没有显示任何中和活性。此外，用 SVP-E2 免疫的小鼠血清可中和含有 E2 N415K 逃逸突变的 HCVtcp。与展示 SVP-E2 表位的颗粒一样，具有 HCV E1 表位的 JEV SVPs 也可诱导针对 HCV 的中和抗体。因此，这种表面带有外来表位的新型平台可能有助于开发针对 JEV 和其他病原体的二价疫苗。
