DNA vaccination is based on in vivo delivery of plasmids encoding an antigen, leading to antigen synthesis and specific immunity. This technology is still in its infancy but has advantages over conventional vaccination, such as the stimulation of all arms of the immune response, i.e., humoral immunity, T-helper (17h) cells and cytotoxic T lymphocytes (CTLs). We studied DNA vaccination against human carcinoembryonic antigen (CEA) in mice. Our hypothesis was that codelivery of cytokine- and CEA-encoding plasmids could regulate responses, and allow polarization of Th responses to either type 1 (Th1) or type 2 (Th2). We found that intramuscular injection of the CEA plasmid alone induced antibodies, Th1 cells and CTLs reactive to CEA. These mice had increased immunity against transplanted syngeneic CEA+ stably transfected tumor cell lines, but always developed lethal tumors. Coinjection of the CEA plasmid with a vector encoding either IL-12 or interferon gamma (IFNgamma) markedly enhanced IgG2a production (IFNgamma-dependent), IFNgamma secretion by spleen cells (a Th1 cytokine) and CTL-mediated tumor cell lysis, in a CEA-specific way. Moreover, resistance to a tumor challenge was greatly improved, such that up to 80% of mice survived tumor free. In contrast, coinjection of CEA and IL-4 genes increased CEA-specific IgG1 levels (IL-4-dependent) and IL-4 secretion by lymphocytes (a Th2 cytokine), but decreased both CTL activity and tumor resistance. Thus, we could readily enhance or polarize immunity. The IL-12 cDNA had the strongest adjuvant effect, which was only observed when it was injected at the same site as the CEA gene. To analyze effector components, we studied IL-12-plasmid-enhanced DNA vaccination in gene knockout mice, lacking either CD3, CD4, CD8. IFNgamma, perforin or Fas ligand (FasL). Only mice expressing all of CD3, CD4, IFNgamma, CD8 and perforin, and inoculated with both the CEA and IL-12 genes, could fully resist a tumor challenge. The Fas/FasL lytic
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.36837 |
| Date | January 2000 |
| Creators | Song, Keli, 1955- |
| Contributors | Prud'homme, Gerald J. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Biochemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001770800, proquestno: NQ69935, Theses scanned by UMI/ProQuest. |
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