Construction of ORF5 gene vaccine against PRRSV and detection of its safety and immunogenicity

ORF5 cDNA cloning and sequencing analysis of porcine reproductive and respiratory syndromevirus (PRRSV) SC2 strain showed that the strain belonged to PRRSV American type. The constructed ORF5 gene vaccinewas transferred into Marc-145 cell line. Intense fluorescence could be observed at 26th hour post-transfection(PT) in the Marc-145 cells and the amount of fluorescence peaked at 56th hour PT. The ORF5 gene could be detected by PCR from tissues and organs of mice and pigs immunized with the ORF5 gene vaccineby intramuscular injection. The ORF5 gene was not integrated into the chromosomes of the animal. Humoral and cellular immuneresponses were obtained in pigs by intramuscular injectionand gene gun transferroutes and persisted for more than 135 days. The results indicated that the ORF5 gene vaccineis immunogenicand safety.