Research On Bivalent Genetic Engineering Vaccine Against Foot-and-mouth Disease And Pseudorabies,and Trivalent Vaccine Against Foot-and-mouth Disease,Porcine Parvovirus Disease And Pseudorabies

Pseudorabies (PR), foot-and-mouth disease (FMD), and porcine parvovirus disease are three important infectious diseases in swine worldwide. The gene-deleted pseudorabies virus (PRV) has been used as the vaccine for eradication program of PR and a live-viral vector to develop bivalent or multivalent genetic engineering vaccine. In this study, A recombinant plasmid pEPl-2A-3C was constructed by inserting the P1-2A structural protein precursor gene and proteinase 3C gene of FMDV into PRV expression vector pIECMV. The genomic DNA of PRV TK/gE/LacZ+ strain and pEEPl-2A-3C were co-transfected into PK-15 cell with lipofection, and purified recombinant virus PRV TK'/gE7Pl-2A-3C was screened out with PCR method by examining P1-2A-3C gene. The recombinant virus was confirmed by PCR and Western blot assay, and the test of virus titers showed that insertion of P1-2A-3C gene did not influence proliferation of recombinant virus. Its virulence was reduced considerably and equaled with that of parent strain PRV TK7gE7LacZ+, and PRV TK7gE7Pl-2A-3C is genetically stable for at least 20 passages. Compared with other controlling groups, mice injected by PRV TK7gE7Pl-2A-3C were induced higher anti-FMDV antibody titer. The recombinant virus should be useful for the further research of bivalent genetic engineering vaccine against FMD and pseudorabies.Gene fragment of capsid proteins precursor P1-2A of FMD virus and VP2 gene of porcine parvovirus were chosen as the target antigen genes. Based on homologous recombination, a recombinant PRV co-expressing protein precursor P1-2A of FMDV and VP2 protein of PPV had been constructed using PRV TK7gE7LacZ+ mutant as the vector virus. By plaque purification and PCR detection, recombinant virus PRV TK7gE7P1-2A-VP2 was acquired. To evaluate its immunogenicity, BALB/c mice were vaccinated with the recombinant PRV, and the humoral response was measured by indirect ELISA and a serum neutralization test (SNT). After booster inoculation, mice sera showed high titers of antibodies against PRV, FMDV and PPV both in ELISA and SNT. Safety of the recombinant PRV and its protection against PRV were confirmed in a mouse model. The results indicate that the recombinant PRV would be a suitable candidate vaccine strain to develop a novel trivalent vaccine against PRV, FMDV and PPV in the pig industry.