表达丙型肝炎病毒多个融合抗原的复制型DNA 疫苗在小鼠体内免疫原性的研究

Evaluation of the immunogenicity of recombinant replicative DNA vaccines expressing multiple anti-gens of hepatitis C virus in a mice model

目的：探索新型的基于丙型肝炎病毒（ HCV）多个靶抗原的复制型DNA疫苗的免疫效果。方法本研究构建了两种表达基于HCV中国1b代表株（河北株）多个靶抗原的复制型DNA疫苗：pSCK-CE1E2Y（核心蛋白Core、包膜蛋白E1、E2抗原）和pSCK-H155（Core、E1、E2、非结构蛋白NS3融合抗原），蛋白印迹试验分析靶抗原表达，皮内电转法免疫BALB／c小鼠后评价其免疫应答，采用表达异型（ JFH1，2 a型） HCV多聚蛋白的重组痘苗病毒接种的小鼠攻击替代模型进行保护效果分析。结果蛋白印迹试验表明DNA疫苗中靶抗原体外可有效表达；两种DNA疫苗均可诱导多抗原特异的抗体反应及T细胞免疫应答；未检测到明显的交叉免疫保护。结论两种复制型DNA疫苗均可诱导针对多抗原的体液及细胞免疫应答，但不能诱导有效的交叉保护。本研究为HCV新型疫苗研制提供了一定参考。

Objective To investigate the immunogenicity and cross protective effects of two novel HCV DNA vaccines in a mice model.Methods Two self-replicating alphavirus vector-based HCV DNA vaccines, pSCK CE1E2Y and pSCK H155, were constructed based on the genes encoding the structural pro-teins （Core, E1 and E2） and structural and NS3 fusion proteins （Core, E1 , E2 and NS3） of a HCV strain isolated from a Chinese patient （genotype 1b, Hebei strain）, respectively.Western blot analysis was per-formed to detect the expression of fusion antigens.The BALB/c mice were intradermally immunized with the recombinant DNA vaccines by using electroporation.The immune responses induced in mice and the cross protective effects of the recombinant DNA vaccines were evaluated.Results The DNA vaccines effectively expressed the target antigens in vitro.The antigen-specific antibody responses and specific T cell immune re-sponses were induced in mice by the immunization of replicative DNA vaccines.However, no effective cross protection was provided by either of the DNA vaccines in the surrogate challenge model based on a recombi-nant heterologous HCV （JFH1, 2a） vaccinia virus strain.Conclusion Although no effective cross protec-tion was observed, both of the two replicative DNA vaccines could induce strong humoral and cellular im-mune responses against multi-target antigens of HCV strains.This study has paved the way for further inves-tigation on the development of novel HCV vaccines.