Construction of Recombinant Porcine Reproductive and Respiratory Syndrome Virus Expressing CSFV E2 Glycoprotein

Classical Swine Fever (CSF) and Porcine Reproductive and Respiratory Syndrome (PRRS) are two highly contagious infectious diseases caused by CSF virus (CSFV) and PRRS virus (PRRSV), respectively. Recombinant PRRSV expressing CSFV E2 glycoprotein could be used for the development of bivalent vaccine, antiviral drug or antibody screening assays against PRRSV and CSFV. In this study, a recombinant PRRSV expressing CSFV E2 glycoprotein (p129-CSFV-E2) was constructed. The E2 gene from CSFV C-strain vaccine was cloned and inserted between ORF1b and ORF2 gene of the PRRSV P129 strain. An additional transcriptional regulatory sequence 6 (TRS6) was inserted following the CSFV E2 for driving the transcription of ORF2. The construct efficiently produced progeny viruses and the expressed CSFV E2 protein was detected by immune staining of infected MARC145 cells.The growth ability of the p129-CSFV-E2 virus is comparable to the parental p129 virus. The genetic stability and stable expression of CSFV E2 of P129-CSFV-E2 virus could reach 11 passages in cell culture. The results showed that CSFV E2 glycoprotein could be expressed as a separated subgenomic unit in the PRRSV genome. The recombinant P129-CSFV-E2 virus can be useful for the development of novel vaccines, cell-based high throughput antiviral drug and antibody screening system against PRRSV and CSFV.