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United States Department of Agriculture

Agricultural Research Service

Title: Comparison of the Protective Response Induced by Nyvac Vaccinia Recombinants Expressing Either Gp50 Or Gii and Gp50 of Pseudorabies Virus

Authors
item BROCKMEIER, SUSAN
item Mengeling, William

Submitted to: Canadian Journal of Veterinary Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 15, 1996
Publication Date: N/A

Interpretive Summary: Pseudorabies is a disease of significant importance to the swine industry to warrant an eradication program. Currently, the recommendation in many eradication programs is to use gene deleted "marker" pseudorabies virus vaccines which allow the differentiation of vaccinated from naturally infected animals. An emerging vaccination strategy is the use of poxviruses that act as a carrier or vector of genes from other viruses. Vectored vaccines could have certain advantages in such an eradication program because they eliminate use of the disease causing virus and they have great potential for differential testing because only genes that elicit a good immune response are included. In this study, there did not appear to be a large difference in protection afforded by multiple pseudorabies virus glycoproteins (gII and gp50) delivered by a vaccinia (a poxvirus) vector over the protection elicited when just gp50 was expressed by the vaccinia vector alone. This may be significant in differential testing for the pseudorabies eradication program. Currently, killed or modified-live marker vaccines used in differential testing are limited to deletions of nonessential glycoprotein genes; but with a vaccinia vectored subunit vaccine, a differential test for an essential gene such as gII is possible. Also, the live viral vector maintains the advantages of modified-live vaccines over killed virus or subunit vaccines. Since gII is an essential gene and the most abundant glycoprotein of the pseudorabies virus genome, it should be an excellent choice for differential testing.

Technical Abstract: A vaccinia vector containing genes for pseudorabies virus glycoproteins gII and gp50 was administered to pigs to determine if they would have a greater protective effect than a vector containing the gene for gp50 alone. Both constructs protected pigs similarly from virulent pseudorabies virus challenge. This may be significant in differential testing for the pseudorabies eradication program. Currently, killed or modified-live marker vaccines used in differential testing are limited to deletions of nonessential glycoprotein genes, but with a vaccinia vectored subunit vaccine a differential test for an essential gene such as gII is possible. Also, the live viral vector maintains the advantages of modified-live vaccines over killed virus or subunit vaccines. Since gII is an essential gene and the most abundant glycoprotein of the pseudorabies virus genome it should be an excellent choice for differential testing.

Last Modified: 9/10/2014
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