Liu Zehui, Liu Yangkun, Zhang Yuanyuan, Yang Yajuan, Ren Jingjing, Zhang Xiaoying, Du Enqi
College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
Vet Res. 2017 May 12;48(1):29. doi: 10.1186/s13567-017-0434-5.
Baculovirus-mediated gene transfer has been developed as a vaccine design strategy against a number of diseases without apparent viral replication. However, it has been hampered by complement-dependent inactivation, thus hindering the in vivo application of baculovirus. A variety of approaches have been exploited to bypass the complement system in the serum. In this study, we constructed and screened a series of baculovirus vectors displaying complement interfering factors, of which a baculovirus vector displaying swine IgG1 Fc (pFc) showed the highest complement antagonism (75.6%). Flow cytometry analysis of transduced cells demonstrated that the baculovirus display of pFc had a significant increase in transduction efficiency and transgene expression of reporter genes. On this basis, a VSV-G-pseudotyped with swine IgG1 Fc surface displayed baculovirus vector was developed to express the classical swine fever virus (CSFV) E2 gene. The translational enhancers Syn21 and P10UTR were incorporated to improve the antigen expression. The E2 gene was efficiently expressed in both insect and mammalian cells. Pigs immunized with this recombinant baculovirus developed high levels of E2-specific antibody, CSFV-specific neutralizing antibody and IFN-γ-secreting cellular immune responses. These results demonstrate that the strategy of surface-displaying swine IgG1 Fc has a great potential to improve the efficiency of baculovirus-vectored vaccine for CSFV and other swine pathogens.
杆状病毒介导的基因转移已被开发为一种针对多种疾病的疫苗设计策略，且无明显病毒复制。然而，它受到补体依赖性失活的阻碍，从而妨碍了杆状病毒在体内的应用。人们已采用多种方法来绕过血清中的补体系统。在本研究中，我们构建并筛选了一系列展示补体干扰因子的杆状病毒载体，其中展示猪IgG1 Fc的杆状病毒载体（pFc）表现出最高的补体拮抗作用（75.6%）。对转导细胞的流式细胞术分析表明，pFc的杆状病毒展示使报告基因的转导效率和转基因表达显著增加。在此基础上，开发了一种表面展示猪IgG1 Fc的VSV-G假型化杆状病毒载体，以表达经典猪瘟病毒（CSFV）E2基因。引入翻译增强子Syn21和P10UTR以提高抗原表达。E2基因在昆虫和哺乳动物细胞中均能有效表达。用这种重组杆状病毒免疫的猪产生了高水平的E2特异性抗体、CSFV特异性中和抗体和分泌IFN-γ的细胞免疫反应。这些结果表明，表面展示猪IgG1 Fc的策略在提高杆状病毒载体疫苗针对CSFV和其他猪病原体的效率方面具有巨大潜力。
