In vitro and in vivo evaluation of two DNA vaccine candidates

Zlei, Mihaela (2002) In vitro and in vivo evaluation of two DNA vaccine candidates. MSc(R) thesis, University of Glasgow.

Abstract

DNA vaccinology, although still in its infancy, has raised a great wave of interest among researchers, due to its wide applicability and the potential advantages it appears to offer over traditional methods of vaccination. In this study two independent bacterially derived antigens were evaluated as DNA vaccine candidates. The main thrust being to determine the potential of these vaccines to express antigen in vitro and stimulate immune responses in vivo. In addition, the route of immunisation on the magnitude and orientation of the immune response to the encoded antigens was also considered, with mice immunized either intramuscularly or intradermally using a Gene Gun. One of the candidates, a DNA vaccine encoding a Mycobacterium bovis antigen (MPB-70) expressed very effectively in vitro when transfected into COS-7 cells. However, it failed to stimulate an immune responses in mice, regardless the route of immunisation used. In contrast, a second bacterial antigen. Fragment C of tetanus toxin produced by Clostridium tetani, expressed poorly in eukaryotic cells but elicited a specific immune response in vaccinated mice. Although, the magnitude of these responses did not appear to differ when mice were immunized using intramuscular or intradermal immunisation using the Gene-Gun, the quality of the immune response generated varied considerably. These results demonstrated that vaccination of pcDNA3/tetC by intramuscular route was associated with a specific anti-Fragment C humoral and cellular response associated with Th1 CD4 cells, whilst immunisation using the Gene-Gun appeared to bias the response toward a CD4 associated Th2 profile. Moreover, both methods were able to prime a specific immune response with a magnitude that could be improved when the mice were boosted using the purified Fragment C antigen. Boosting these animals in such a manner resulted in an improvement in the magnitude of the immune response generated, however, the orientation of this response remained faithful to that originally initiated by the original route of DNA vaccination. Interestingly, the Gene- Gun mediated immunisation appeared to be far more efficient at stimulating immune responses as the magnitude of the immune response to the antigen was unaffected despite only a fiftieth of the amount of DNA used for each immunisation. This work highlights the potential impact of immunisation route on the quality and magnitude of an immune response to Fragment C when delivered as a DNA vaccine.

• Item Type: Thesis (MSc(R))
• Qualification Level: Masters
• Additional Information: Adviser: Gill Douce
• Keywords: Pharmacology
• Date of Award: 2002
• Depositing User: Enlighten Team
• Unique ID: glathesis:2002-72825
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 11 Jun 2019 11:06
• Last Modified: 11 Jun 2019 11:06
• URI: https://theses.gla.ac.uk/id/eprint/72825