Chen Nanhua, Li Shubin, Li Xinshuai, Ye Mengxue, Xiao Yanzhao, Yan Xilin, Li Xiangdong, Zhu Jianzhong
College of Veterinary Medicine, Yangzhou University, Yangzhou, P.R. China.
State Key Laboratory of Genetically Engineered Veterinary Vaccines, Qindao, P.R. China.
Transbound Emerg Dis. 2020 Sep;67(5):1820-1827. doi: 10.1111/tbed.13575. Epub 2020 Apr 30.
Multiple commercial porcine reproductive and respiratory syndrome (PRRS) modified live vaccines are currently utilized in Chinese swine herds due to the limited cross-protection of vaccines and coexistence of different PRRS viruses. In this study, an infectious cDNA clone of the highly pathogenic PRRS (HP-PRRS) vaccine JXA1-R strain was generated. We successfully rescued the virus from direct in vitro DNA transfection of rJXA1-R clone, which has similar growth kinetics to the parental JXA1-R virus in Marc-145 cells. To further evaluate the potential use of the cloned rJXA1-R virus as a live vector for foreign gene expression, the enhanced green fluorescent protein (EGFP) was inserted between non-structural and structural genes. Our results showed that the dynamic expression of EGFP can be visualized by live cell imaging system during the infection in Marc-145 cells. The availability of our cloned JXA1-R viruses provides a crucial platform to study the fundamental biology of HP-PRRS virus vaccine and also serves as a potential effective vector for developing live vector vaccines against swine pathogens.
由于疫苗交叉保护有限以及不同猪繁殖与呼吸综合征（PRRS）病毒共存，目前多种商业性PRRS弱毒疫苗在中国猪群中使用。在本研究中，构建了高致病性PRRS（HP-PRRS）疫苗JXA1-R株的感染性cDNA克隆。我们通过rJXA1-R克隆的直接体外DNA转染成功拯救出病毒，该病毒在Marc-145细胞中的生长动力学与亲本JXA1-R病毒相似。为进一步评估克隆的rJXA1-R病毒作为外源基因表达活载体的潜在用途，在非结构基因和结构基因之间插入了增强型绿色荧光蛋白（EGFP）。我们的结果表明，在Marc-145细胞感染期间，通过活细胞成像系统可观察到EGFP的动态表达。我们克隆的JXA1-R病毒的获得为研究HP-PRRS病毒疫苗的基础生物学提供了关键平台，也可作为开发针对猪病原体的活载体疫苗的潜在有效载体。
