Immunogenicity of a recombinant pseudorabies virus coexpressing ORF2 gene of PCV2 and porcine IL-18 gene in mice

Abstract:

[Objective] To develop a bivalent vaccine against pseudorabies virus(PRV) and porcine circovirus(PCV2), IL-18 was used as immunologic adjuvant.[Methods] Porcine IL-18 gene was inserted into vector pGO. The obtained recombinant transfer plasmid pGO18 was transfected into ST cells with PRV attenuated vaccine HB98 strain. Then plaque selection and purification were performed to obtain purified recombinant virus PGO18. RT-PCR and Western blot were used to demonstrate the expression of PGO18 from transcription and protein levels, respectively. Six-week-old female Kunming mice were immunized with recombinant virus PGO18 and PGO, commercial PCV2 inactivated vaccine, PRV attenuated vaccine HB98 strain, 1640 medium. Mice were vaccinated twice 4 weeks later and then challenged with the virulent PCV2 DF strain and PRV Min/A strain 4 weeks after the second immunization. ELISA, serum neutralization assay, flow cytometry and protect experiment were used to demonstrate the immunity of mice.[Results] The recombinant virus PGO18 was obtained, and it could express on ST cells. Mice vaccinated with PGO18 elicited high levels of humoral and cell immune response, and could also be protected against PCV2 and PRV challenge.[Conclusion] The recombinant virus possessed high safety and good immunogenicity. It may be a candidate vaccine strain against PCV2 and PRV infection.