Date of Award

2009

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biology

Abstract

Objectives . In the process of designing vaccines, the inclusion of adjuvants becomes increasingly important, especially tumor-associated plasmid DNA and its expressing peptide idiotypic (Id) regions of immunoglobulin, which have relatively weak immunogenicity. Here, we report on the CpG1826 and Phytol-based adjuvant PHIS-01, and their efficacies on DNA and recombinant protein vaccines against lymphoma models 2C3 and A20. Our objective of this study is to test and evaluate the efficacy in augmenting the immune responses and protecting the mice against the tumor growth. Methods . We explored two main immunization routes, intra-splenic and intra-peritoneal for 2C3 and A20 model respectively. We constructed plasmid encoding 2C3 idiotype conjugated with tetanus toxin T helper epitope, chose CpG 1826 as an additional vaccine adjuvant. We also purified A20 idiotype conjugated with mycobacteria heat shock protein (mycHSP) recombinant proteins and chose phytol derivate PHIS-01 as an additional vaccine adjuvant. Results . The addition of stimulatory CpG ODN1826 to the 2C3 tumor system enhances the immunogenicity of a DNA vaccine construct, Id-Th. The Id-Th DNA plasmid plus CpG provides better protection (53.8% survival rate) than Id-Th alone. In the A20 model, addition of PHIS-01 to A20 Id recombinant protein vaccines makes them more efficacious than vaccines without it. A20 Id primed mice splenocytes show significantly higher levels of proliferative responses after re-stimulation with the recombinant idiotypic protein A20 in vitro . Re-stimulation with live and killed A20 cells yields similar results. Recombinant protein A20 or A20HSP and PHIS-01 primed mice also show higher NO release when re-stimulated with the live A20 cells in vitro . Following vaccination with recombinant protein A20 or A20HSP and PHIS-01, 10-20% mice experience long term protection against 5X10 5 A20 tumor challenge. Conclusion . Adjuvants significantly improve idiotypic immunogenicity in both vaccine designs when used in the right formulation and appropriate routes of immunization.

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