Degree Type

Dissertation

Date of Award

1996

Degree Name

Doctor of Philosophy

Department

Veterinary Microbiology and Preventive Medicine

First Advisor

William L. Mengeling

Second Advisor

Michael J. Wannemuehler

Abstract

This study evaluated vaccinia-vectored vaccines expressing glycoproteins gB, gC, or gD of pseudorabies virus (PRV) in pigs. The vaccines are based on an attenuated vaccinia virus strain, NYVAC, which has reduced virulence and replicative capacity for certain species, including swine. The recombinant vaccinia vaccines were unable to prevent replication of virulent pseudorabies virus or latency but they were able to decrease the amount of virus shed after challenge and decrease clinical signs. In particular, pigs vaccinated with the recombinants expressing either gB or gD were protected at a level comparable to an inactivated PRV virus that was given for comparison. No lesions or clinical signs were seen following vaccination in these studies and no seronegative pigs in contact with vaccinia-vaccinated pigs ever seroconverted. No significant increase in protection occurred by giving recombinants expressing multiple glycoproteins and there was no virus neutralizing antibody response or protection induced when the recombinant vaccines were given orally or intranasally. The response to the recombinants is dose dependent but there was no indication that prior immunity to the vaccinia parent virus had any inhibitory effect on subsequent vaccination with these recombinants. The gB recombinant, but not the gD recombinant, was able to stimulate an active immune response in piglets with passive immunity from PRV or NYVAC/gD vaccinated dams. The NYVAC/PRV recombinant vaccines were compatible with differential serologic tests currently on the market. We could not demonstrate significant cell-mediated immune responses after vaccination with the recombinant vaccines but they may prime this type of response. In summary, the NYVAC/PRV recombinant vaccines afforded protection comparable with that of PRV vaccines currently on the market, were safe, and offer some advantages over currently available vaccines such as elimination of attenuated PRV viral strains, better induction of immunity in the presence of passive immunity, and more sensitive differential testing capabilities.

DOI

https://doi.org/10.31274/rtd-180813-10542

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Susan Lisa Brockmeier

Language

en

Proquest ID

AAI9712545

File Format

application/pdf

File Size

153 pages

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