Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Veterinary Microbiology and Preventive Medicine

First Advisor

Prem S. Paul


The hypothesis tested in this dissertation is that a poxvirus vector system containing influenza virus immunogens protects pigs against swine influenza virus (SIV)-associated disease. The host range-restricted, highly attenuated, and safety-tested modified vaccinia virus Ankara (MVA) strain was used as a vector for influenza virus hemagglutinin (HA) and nucleoprotein (NP) genes from the H1N1 A/PR/8/34 (PR8) human isolate. This recombinant virus has previously been shown to protect mice against lethal challenge with PR8. First, the ability of the MVA/PR8 recombinant to protect pigs against SIV was examined. Second, a new recombinant, designated MVA/SIV, was constructed containing the HA and NP genes from a field isolate of SIV submitted to the Iowa State University Veterinary Diagnostic Laboratory. The MVA/SIV recombinant was evaluated for immunogenicity in vaccinated pigs subsequently challenged with SIV. Third, the possibility of inhibition of immune response in secondary vaccination, following sequential use of two MVA recombinants, was explored using the MVA/PR8 and MVA/SIV constructs. The first study demonstrated that protection afforded by MVA/PR8 against SIV was less than complete, that infection, clinical signs of illness, and viral shedding still occurred, albeit to a lesser degree than in nonvaccinated controls. The second study indicated the marked improvement in protection against SIV when pigs were vaccinated with the MVA/SIV construct. The third study provided evidence that sequential use of such MVA recombinants containing inserts from two strains of influenza virus, given two months apart, still generated appropriate immune responses to the different inserts.



Digital Repository @ Iowa State University,

Copyright Owner

Patricia Louise White Foley



Proquest ID


File Format


File Size

148 pages