To construct the bi-valent genetic engineering vaccine against pseudorabies virus（PRV）and porcine reproductive and respiratory syndrome virus（PRRSV）,the modified PRRSV ORF5 gene（ORF5M） and the VP22 gene of bovine herpesvirus 1（BHV-1）,which encodes VP22 protein and has been demonstrated to exhibit the unusual protein transduction property,were inserted into a PRV universal transfer vector pIECMV by turns.A recombinant virus transfer vector pIECMV-VP22ORF5M possessing VP22-ORF5M fusion gene was generated.The recombinant virus transfer vector pIECMV-VP22ORF5M co-transfected the IBRS-2 cells with PRV TK-/gE-/LacZ+ genomic DNA digested by EcoRⅠusing liposome method.Based on homologous recombination,the recombinant virus was generated and then purified by the plaque assay and PCR amplification.After three rounds of plaque purification,the recombinant virus was further confirmed by PCR,Southern blot and Western blot.A recombinant PRV（rPRV）TK-/gE-/VP22GP5+ expressing VP22-GP5 fusion protein was constructed.The results of TCID50 tests showed that the insertion of the foreign genes had no influence on the propagation of rPRV in IBRS-2 or PK-15 cells.The construction of rPRV TK-/gE-/VP22GP5+ provides a basis for further study of bi-valent genetic engineering vaccines against PRRSV and PRV,and that this strategy may also be useful to develop more efficient genetic engineering vaccines against other pathogens.
PCV1 was isolated from IBRS-2 cells line,and its complete genomic sequence was cloned by PCR.Sequence analysis indicated that this PCV1 strain shares >98% nucleotide identity with the other PCV1 strains in GenBank.Then double copy molecule clone(pSK2PCV1) was constructed and used to transfect PK-15 cell line.The results of indirect immunofluorescence(IIF) and RT-PCR suggested that pSK2PCV1 could form infectious virus after being transfected into PK-15 cells.
