Jiang Yifeng, Gao Fei, Li Liwei, Zhou Yanjun, Tong Wu, Yu Lingxue, Zhang Yujiao, Zhao Kuan, Zhu Haojie, Liu Changlong, Li Guoxin, Tong Guangzhi
Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.
Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonosis, Yangzhou University, Yangzhou, China.
Front Vet Sci. 2023 Mar 7;10:1128863. doi: 10.3389/fvets.2023.1128863. eCollection 2023.
Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) and Classical Swine Fever Virus (CSFV) are two important pathogens, which cause serious impact on swine industry worldwide. In our previous research, rPRRSV-E2, the recombinant PRRSV expressing CSFV E2 protein, could provide sufficient protection against the lethal challenge of highly pathogenic PRRSV and CSFV, and could maintained genetically stable . Here, to evaluate the virulence reversion potential risk, rPRRSV-E2 had been continuously passaged , the stability of E2 expression and virulence of the passage viruses were analyzed. The results showed that no clinical symptoms or pathological changes could be found in the inoculated groups, and there were no significant differences of viraemia among the test groups. Sequencing and IFA analysis showed that the coding gene of exogenous CSFV E2 protein existed in the passaged viruses without any sequence mutations, deletions or insertions, and could expressed steadily. It could be concluded that the foreign CSFV E2 gene in the genome of rPRRSV-E2 could be maintained genetically stable , and rPRRSV-E2 strain had relatively low level of potential risk for virulence reversion.
猪繁殖与呼吸综合征病毒（PRRSV）和猪瘟病毒（CSFV）是两种重要的病原体，它们对全球养猪业造成严重影响。在我们之前的研究中，表达CSFV E2蛋白的重组PRRSV rPRRSV-E2能够为抵抗高致病性PRRSV和CSFV的致死性攻击提供充分保护，并且能够保持遗传稳定性。在此，为评估毒力返强的潜在风险，对rPRRSV-E2进行连续传代，并分析传代病毒的E2表达稳定性和毒力。结果显示，接种组未发现临床症状或病理变化，各试验组之间的病毒血症无显著差异。测序和免疫荧光分析表明，传代病毒中存在外源CSFV E2蛋白的编码基因，且无任何序列突变、缺失或插入，能够稳定表达。可以得出结论，rPRRSV-E2基因组中的外源CSFV E2基因能够保持遗传稳定，rPRRSV-E2毒株的毒力返强潜在风险相对较低。
