EVALUATION OF SWINEPOX VIRUS AS A VACCINE VECTOR IN PIGS USING AN AUJESZKYS-DISEASE (PSEUDORABIES) VIRUS GENE INSERT CODING FOR GLYCOPROTEINS GP50 AND GP63

Pigs were vaccinated by scarification or intramuscular injection with a swinepox virus-Aujeszky's disease (pseudorabies) recombinant (rSPV-A D) constructed by inserting the linked Aujeszky's disease virus genes coding for glycoproteins gp50 and gp63, attached to a vaccinia virus p 7.5 promoter, into the thymidine kinase gene of swinepox virus. By 21 days after vaccination, 90 and 100 per cent of the animals vaccinated by scarification or intramuscular injection, respectively, had develop ed serum neutralising antibodies to Aujeszky's disease virus. Upon cha llenge with virulent virus, significantly fewer vaccinated pigs develo ped clinical Aujeszky's disease, nasal shedding of challenge virus was markedly reduced, and the vaccinated groups of pigs maintained or gai ned weight during the week after challenge whereas the unvaccinated co ntrol group lost weight. No transmission of rSPV-AD to in-contact cont rols was detected during the three weeks before challenge. In a second experiment, serum neutralising antibodies to Aujeszky's disease virus persisted for 150 days after the pigs were vaccinated with rSPV-AD by scarification or intramuscular injection and all the pigs showed an a namnestic response when they were revaccinated.