Identifier

etd-10302008-133452

Degree

Doctor of Philosophy (PhD)

Department

Veterinary Medical Sciences - Pathobiological Sciences

Document Type

Dissertation

Abstract

West Nile virus (WNV) was first isolated in 1937 from a febrile Ugandan woman. WNV now has a worldwide distribution from Australia and India in the east to Europe and the United States in the west. The first human cases of WNV in the United States were detected in New York in 1999. The North American isolates were also found to be highly neuroinvasive and neurovirulent and in many cases leading to mortality or permanent CNS sequelae among humans. WNV was first isolated in Louisiana in 2001. The genome of this virus named LSU-AR01was sequenced and a detailed genetic analysis revealed 26 amino acid changes in comparison to the prototypic New York-99 strain. Phylogenetic analysis using Neighbor-joining and the Bayesian approach showed that LSU-AR01 was closely related to a strain isolated from a mosquito in 1999 in Connecticut. This relationship was bolstered by a 58% bootstrap value and a 66% posterior probability by these algorithms respectively. Comparative pathology revealed that the LSU-AR01 was more neurovirulent and neuroinvasive especially at low doses indicating a virus with a competitive edge. Recombinant vesicular stomatitis virus (rVSV) based vaccines cleverly incorporate reverse genetics to recover a recombinant virus expressing a foreign antigen of interest. rVSV vectored vaccines expressing the LSU-AR01 envelope (E) glycoprotein were engineered and administered to mice in a prime-boost approach. The vaccines were able to confer high degree of protection in mice against lethal challenge with highly virulent WNV LSU-AR01. Detailed immunological analyses of immunized mice revealed the production of neutralizing antibody responses. In addition, vaccinated mice generated WNV E glycoprotein specific CD8+CD62Llow IFNã+ T cells response against WNV. Recombinant VSV expressing the Simian Retrovirus-2 (SRV-2) gag and Env gene constructs and the Herpes B virus glycoprotein D gene were constructed and characterized in cell culture experiments. The VSV-SRV-2 gag and env recombinants generated protective immune responses in non-human primates. The VSV Herpes B recombinant vaccine will be tested in non-human primates in the near future. Collectively, these experiments revealed that VSV-vectored vaccines are highly effective in generating humoral and cellular immune responses against viral infections.

Date

2008

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Kousoulas, Konstantin Gus

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