Cationic Lipsomes Promote in Vivo Transfection, Innate Immunity Activation and Antigen-Specific CD8+ T-Cell Activation Following Vaccination with Piggybac DNA Plasmids
Year: 2015
Type: article
Abstract: INTRODUCTION: DNA vaccination with plasmid has conventionally involved vectors designed for transient expression of antigen in injected tissues. Next generation plasmids are being developed for site-directed integration of transgenes into safe sites in host genomes and may provide an innovative approach for stable and sustained expression of antigens for vaccination. In our previous study, we have demonstrated the improved efficacy of site-directed integration using hyperactive piggyBac transposase-based integrating vectors (pmhyGENIE-3) over non-integrating plasmids. Adjuvant technologies such as AdjuplexTM may further improve vaccine efficacy by producing a strong immunostimulatory effect to elicit more potent immune responses via both cell-mediated and antibody-mediated mechanisms. STUDY DESIGN: The goal of this study was to evaluate in vivo antigen expression and the generation of cell mediated immunity in mice injected with plasmids and various adjuvants. The efficacy of AdjuplexTM to promote antigen expression and CD8+ T cell activation after vaccination with pmhyGENIE-3 was compared with the efficacy of two other adjuvants: liposomes, jetPEIU. Groups of mice injected with pmhyGENIE-3 expressing luciferase (pmhyGENIE-GL3) and adjuvants were used to compare antigen expression. In another experiment, mice injected with pmhyGENIE-3 plasmids expressing eGFP (pmhyGENIE-3-eGFP) with different adjuvants were used to compare eGFP-specific T cell activation. RESULTS: When luciferase activity was measured using IVIS imaging, mice vaccinated with pmhyGENIE-3-GL3 and AdjuplexTM showed the strongest antigen expression at 28 days after subcutaneous injection. Flow cytometry analysis of blood cells, using antigen-specific pentamers, demonstrated that vaccination with pmhyGENIE-3-eGFP and Adjuplex TM generate higher numbers of CD8+ T cells when compared with liposomes and jetPEIU. Analyses of eGFP peptide-pulsed spleen cells from vaccinated mice using ELISPOT and intracellular cytokine staining confirmed higher antigen-specific, interferon-γ-producing CD8+ T-cell responses after vaccination using AdjuplexTM. CONCLUSIONS: Overall, these findings suggest that plasmids designed to direct integration of transgenes into the host genome used in conjunction with AdjuplexTM provide a promising approach for DNA vaccines. Robust cell mediated CD8+ T cell responses generated using this vaccine/adjuvant combination may provide effective, sustained immune responses against intracellular pathogen or tumor antigens.
Source: PubMed Central
Language: English
Subfield: Immunology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2462270683