Degree Type

Dissertation

Date of Award

2012

Degree Name

Doctor of Philosophy

Department

Veterinary Microbiology and Preventive Medicine

First Advisor

Randy E. Sacco

Second Advisor

James A. Roth

Abstract

Disease associated with BVDV infection can be devastating ranging to millions of dollars in loss to the cattle industry. As well, infection with BVDV leads to an immune-suppressed host though an unknown mechanism(s). Although there are vaccines available, they are not broadly protective and ineffective in PI cattle. The myeloid lineage cells such as monocytes and MΦ are important in recognizing BVDV as well as initiating an adaptive immune response. There is little information on the effects of BVDV in vivo on the functionality of these cells and a better understanding can lead to potential treatment. Investigating the effects on cytokine production, expression and response of TLRs and functional aspects of phagocytosis are critical. The specific aims in this dissertation studies utilize neonatal calves for in vivo study and 1-year-old cattle for cell donors during in vitro investigation. BVDV-2 strain 1373 was utilized as it is a field strain, which induces severe acute disease and is a highly virulent. BVDV-2 strains RS886 and 28508 are subclinical acute disease inducing strains, which are lower in virulence and typical of field isolates from PI cattle or subclinical infections. BVDV-2 strain 296c is a cytopathic strain whereas BVDV-2 strain 296nc is an isogenic non-cytopathic strain. These isogenic strains were chosen as the only differences between the strains are the NS2/3 coding regions. BVDV-2 strains 1373 and RS886 were utilized for in vivo experimentation whereas BVDV-2 strains 1373, 28508, 296c and 296nc were used for in vitro experiments. Both in vivo and in vitro models were used to characterize viral effects on cytokine expression and secretion, TLR responsiveness, signaling events, and phagocytosis of myeloid cells after exposure to virus.

DOI

https://doi.org/10.31274/etd-180810-1613

Copyright Owner

Robert G. Schaut

Language

en

File Format

application/pdf

File Size

184 pages

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