Induction of multiple cytotoxic T lymphocyte responses in mice by a multiepitope DNA vaccine against dengue virus serotype 1

Dengue virus (DENV) is still a major threat to human health in most tropical and subtropical countries and regions. In the present study, a multi-epitope DNA vaccine that encodes 15 immunogenic and conserved HLA-A*0201-, HLA-A*1101-, HLA-A*2402-restricted CTL epitopes from DENV serotype 1 (DENV-1) was constructed based on the eukaryotic expressing plasmid pcDNA (TM) 3.1/myc-His(-) A. Immunization of HLA-A*0201, HLA-A*1101 and HLA-A*2402 transgenic mice with the recombinant plasmid pcDNA (TM) 3.1/myc-His(-) A-DENV-1-Meg resulted in significantly greater IFN-gamma-secreting T-cell responses against most (14/15) CTL epitopes than occurred in mice immunized with the empty plasmid pcDNA (TM) 3.1/myc-His(-) A. Additionally, the epitope-specific T cells directed to some epitopes secreted not only IFN-gamma but also IL-6 and/or TNF-alpha. Finally, the induced epitope-specific T cells also efficiently lysed epitope-pulsed splenocytes and DENV-1-infected splenic monocytes. The present study confirms the immunogenicity of multi-epitope DENV vaccine, suggesting that it may contribute to the development of a universal DENV vaccine.