Porcine reproductive and respiratory syndrome virus expressing E2 of classical swine fever virus protects pigs from a lethal challenge of highly-pathogenic PRRSV and CSFV

Publication date: 31 May 2018
Source:Vaccine, Volume 36, Issue 23
Author(s): Fei Gao, Yifeng Jiang, Guoxin Li, Yanjun Zhou, Lingxue Yu, Liwei Li, Wu Tong, Hao Zheng, Yujiao Zhang, Hai Yu, Tongling Shan, Shen Yang, Huan Liu, Kuan Zhao, Guangzhi Tong
Porcine reproductive and respiratory syndrome (PRRS) and classical swine fever (CSF) are economically significant diseases that affect the swine industry worldwide. However, the current vaccination strategy, which uses two single live attenuated vaccines, can result in interference for each other. In addition, the universally used CSFV vaccine C-strain does not allow for differentiation of infected and vaccinated animals. In this study, rPRRSV-E2, PRRS virus (PRRSV) expressing CSF virus (CSFV) E2, was constructed by reverse genetics. The E2 gene of CSFV was inserted between ORF1b and ORF2 in the genome of the PRRS vaccine virus, HuN4-F112. A copy of transcriptional regulatory sequence 6 was inserted at the 3′ terminal of the exogenous gene to produce CSFV E2 as a unique subgenomic mRNA transcript. The rPRRSV-E2 was stable for at least 25 serial cell passages. Single-shot intramuscular immunization of rPRRSV-E2 into pigs induced PRRSV-specific and CSFV-specific antibodies and fully protected pigs from lethal challenge with highly-pathogenic PRRSV and CSFV. These results demonstrate that a novel strategy for recombinant PRRSV production is effective, and suggest that rPRRSV-E2 is a promising live, virus-vectored vaccine against PRRS and a marker vaccine against CSF.



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