Document Type

Thesis - Open Access

Award Date

2016

Degree Name

Master of Science (MS)

Department / School

Veterinary and Biomedical Sciences

First Advisor

Diego G. Diel

Keywords

Orf, parapoxvirus, PEDV, vaccine, vector, virus

Abstract

Orf virus (ORFV), the type member of the genus Parapoxvirus of the family Poxviridae, causes orf or cutaneous pustular dermatitis in sheep and goats. ORFV is a ubiquitous virus capable of re-infecting its hosts multiple times over time. ORFV causes a non-systemic, self-limiting disease which is usually restricted to the skin surrounding the virus entry sites. ORFV has evolved several immunomodulatory proteins (IMPs) that evade and/or modulate host immune responses to infection and contribute to virus virulence and disease pathogenesis. Given biological properties and unique immunomodula tor y properties, ORFV has gained significant attention in recent years for its potential as a vaccine delivery vector for use in veterinary medicine. Here we explored the potential of ORFV as a vaccine delivery vector for use in swine. The spike (S) protein of porcine epidemic diarrhea virus (PEDV) was used as our model antigen and the immunogenicity and protective efficacy of a recombinant ORFV expressing the full length S protein of PEDV (ORFV-PEDV-S) was assessed in pigs. The ORFV-PEDV-S virus was generated by homologous recombination and the DNA sequences of PEDV S were inserted into the ORFV121 gene locus, an immunomodulatory protein (IMP) encoded by ORFV that contributes to the virus virulence. The resultant recombinant virus was characterized in vitro and its immunogenicity and protective efficacy evaluated in vivo. Results of our study show that intramuscular (IM) immunization of swine with the ORF-PEDV-S recombinant virus elicited robust humoral immune responses and protected animals from clinica l disease. Additionally, IM immunization with the ORFV-PEDV-S led to reduced virus shedding in feces. The results of this study provide important information on the feasibility of ORFV as a vaccine delivery vector for use in swine.

Library of Congress Subject Headings

Recombinant viruses.
Poxviruses.
Diarrhea in swine.
Swine -- Diseases.
Vaccines.
Virus-vector relationships.

Description

INcludes bibliographical references (pages 49-62)

Format

application/pdf

Number of Pages

77

Publisher

South Dakota State University

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Rights Statement

In Copyright