COMPARISON OF THE PROTECTIVE EFFICACY OF RECOMBINANT PSEUDORABIES VIRUSES AGAINST PSEUDORABIES AND CLASSICAL SWINE FEVER IN PIGS - INFLUENCE OF DIFFERENT PROMOTERS ON GENE-EXPRESSION AND ON PROTECTION

The glycoprotein E (gE) locus in the genome of pseudorabies virus (PRV ) was used as an insertion site for the expression of glycoprotein El of classical swine fever virus (CSFV). Transcription of E1 in the reco mbinants M401, M402 or M403 was regulated by the go promoter of PRV, t he immediate early gene promoter of human cytomegalovirus, or the gE p romoter of PRV, respectively Groups of four pigs were vaccinated once intramuscularly with 10(6) plaque forming units (p.f.u.) Of the recomb inant viruses and challenged intranasally with 100 50% lethal doses of virulent CSFV and with 10(5) p.f.u. of virulent PRV. All pigs vaccina ted with M402 were fully protected against both classical swine fever and pseudorabies.