Animal Biotechnology Center of Sichuan Agricultural University, Ya'an, Sichuan, 625014, PR China.
Virol J. 2011 Jun 16;8:307. doi: 10.1186/1743-422X-8-307.
Porcine parvovirus (PPV) VP2 gene has been successfully expressed in many expression systems resulting in self-assembly of virus-like particles (VLPs) with similar morphology to the native capsid. Here, a pseudorabies virus (PRV) system was adopted to express the PPV VP2 gene.
A recombinant PRV SA215/VP2 was obtained by homologous recombination between the vector PRV viral DNA and a transfer plasmid. Then recombinant virus was purified with plaque purification, and its identity confirmed by PCR amplification, Western blot and indirect immunofluorescence (IFA) analyses. Electronic microscopy of PRV SA215/VP2 confirmed self-assembly of both pseudorabies virus and VLPs from VP2 protein.
Immunization of piglets with recombinant virus elicited PRV-specific and PPV-specific humoral immune responses and provided complete protection against a lethal dose of PRV challenges. Gilts immunized with recombinant viruses induced PPV-specific antibodies, and significantly reduced the mortality rate of (1 of 28) following virulent PPV challenge compared with the control (7 of 31). Furthermore, PPV virus DNA was not detected in the fetuses of recombinant virus immunized gilts.
In this study, a recombinant PRV SA215/VP2 virus expressing PPV VP2 protein was constructed using PRV SA215 vector. The safety, immunogenicity, and protective efficacy of the recombinant virus were demonstrated in piglets and primiparous gilts. This recombinant PRV SA215/VP2 represents a suitable candidate for the development of a bivalent vaccine against both PRV and PPV infection.
猪细小病毒（PPV）VP2 基因已在许多表达系统中成功表达，导致病毒样颗粒（VLPs）自组装，其形态与天然衣壳相似。在此，采用伪狂犬病病毒（PRV）系统表达 PPV VP2 基因。
通过载体 PRV 病毒 DNA 与转移质粒之间的同源重组，获得重组 PRV SA215/VP2。然后通过噬斑纯化法对重组病毒进行纯化，并通过 PCR 扩增、Western blot 和间接免疫荧光（IFA）分析确认其身份。PRV SA215/VP2 的电子显微镜证实了伪狂犬病病毒和 VP2 蛋白自组装的 VLPs。
用重组病毒免疫仔猪可引起 PRV 和 PPV 的体液免疫反应，并对致死剂量的 PRV 攻击提供完全保护。用重组病毒免疫的母猪诱导产生了 PPV 特异性抗体，与对照组（7/31）相比，在强毒 PPV 攻毒后，死亡率显著降低（28 头中的 1 头）。此外，在重组病毒免疫的母猪的胎儿中未检测到 PPV 病毒 DNA。
本研究使用 PRV SA215 载体构建了表达 PPV VP2 蛋白的重组 PRV SA215/VP2 病毒。在仔猪和初产母猪中证明了重组病毒的安全性、免疫原性和保护效力。该重组 PRV SA215/VP2 代表了开发针对 PRV 和 PPV 感染的二价疫苗的合适候选物。
