Assessment of delivery parameters with the multi-electrode array for development of a DNA vaccine against Bacillus anthracis
ABSTRACT Gene electrotransfer (GET) enhances delivery of DNA vaccines by increasing both gene expression and immune responses. Our lab has developed the multi-electrode array (MEA) for DNA delivery to skin. The MEA was used at constant pulse duration (150ms) and frequency (6.67Hz). In this study, delivery parameters including applied voltage (5-45V), amount of plasmid (100-300μg), and number of treatments (2-3) were evaluated for delivery of a DNA vaccine. Mice were intradermally injected with plasmid expressing Bacillus anthracis protective antigen with or without GET and αPA serum titers measured. Within this experiment no significant differences were noted in antibody levels from varying dose or treatment number. However, significant differences were measured from applied voltages of 25 and 35V. These voltages generated antibody levels between 20,000 and 25,000. Serum from animals vaccinated with these conditions also resulted in toxin neutralization in 40-60% of animals. Visual damage was noted at MEA conditions of 40V. No damage was noted either visually or histologically from conditions of 35V or below. These results reflect the importance of establishing appropriate electrical parameters and the potential for the MEA in non-invasive DNA vaccination against B. anthracis.
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- "The vaccination course consisted of two intradermal injections into the skin of the back near the base of the tail. Immediately after the plasmid or FITC-dextran administration, a conducting gel and an electrode were placed over the injection site and voltage was set up according to previously described protocols (2 pulses, 1125 V/cm 50 í µí¼s, and 8 pulses, 275 V/cm 10 msec) . Electrodes conslehisted of two parallel lamellae at 6–8 mm distance. "
ABSTRACT: Skin represents an attractive target for DNA vaccine delivery because of its natural richness in APCs, whose targeting may potentiate the effect of vaccination. Nevertheless, intramuscular electroporation is the most common delivery method for ECTM vaccination. In this study we assessed whether intradermal administration could deliver the vaccine into different cell types and we analyzed the evolution of tissue infiltrate elicited by the vaccination protocol. Intradermal electroporation (EP) vaccination resulted in transfection of different skin layers, as well as mononuclear cells. Additionally, we observed a marked recruitment of reactive infiltrates mainly 6–24 hours after treatment and inflammatory cells included CD11c+. Moreover, we tested the efficacy of intradermal vaccination against Her2/neu antigen in cellular and humoral response induction and consequent protection from a Her2/neu tumor challenge in Her2/neu nontolerant and tolerant mice. A significant delay in transplantable tumor onset was observed in both BALB/c (𝑝 ≤ 0,0003) and BALB-neuT mice (𝑝 = 0,003). Moreover, BALB-neuT mice displayed slow tumor growth as compared to control group (𝑝 < 0,0016). In addition, while in vivo cytotoxic response was observed only in BALB/c mice, a significant antibody response was achieved in both mouse models. Our results identify intradermal EP vaccination as a promising method for delivering Her2/neu DNA vaccine.Journal of Immunology Research 06/2015; 2015(10):10. DOI:10.1155/2015/159145 · 2.93 Impact Factor
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ABSTRACT: The presence of increased temperature for gene electrotransfer has largely been considered negative. Many reports have published on the lack of heat from electrotransfer conditions to demonstrate that their effects are from the electrical pulses and not from a rise in temperature. Our hypothesis was to use low levels of maintained heat to aid in gene electrotransfer. The goal was to increase gene expression and/or reduce electric field. In our study we evaluated high and low electric field conditions from 90 V to 45 V which had been preheated to 40 °C, 43 °C, or 45 °C. Control groups of non-heated as well as DNA only were included for comparison in all experiments. Luciferase gene expression, viability, and percent cell distribution were measured. Our results indicated a 2–4 fold increase in gene expression that is temperature and field dependent. In addition levels of gene expression can be increased without significant decreases in cell death and in the case of high electric fields no additional cell death. Finally, in all conditions percent cell distribution was increased from the application of heat. From these results, we conclude that various methods may be employed depending on the end users desired goals. Electric field can be reduced 20-30% while maintaining or slightly increasing gene expression and increasing viability or overall gene expression and percent cell distribution can be increased with low viability.Bioelectrochemistry 08/2014; 103. DOI:10.1016/j.bioelechem.2014.08.007 · 3.87 Impact Factor
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ABSTRACT: Plasma-based methods have recently emerged as a technique for augmenting plasmid DNA delivery to skin. This delivery modality relies on the deposition of ionized gas molecules on to targeted cells or tissue to establish an electric field. It is hypothesized that this electric field results in the dielectric breakdown of cell membranes, making cells permeable to exogenous molecules. This in vivo investigation sought to optimize the intradermal delivery of a luciferase expressing plasmid DNA by modulating the total exposure to the plasma source and the plasmid DNA dose. Varying the plasma exposure time from 2, 5, 10, and 20 min allowed the conditions resulting in the highest expression of luciferase to be found. These conditions correlated to the 10 minute exposure time for a plasma derived from either + 8 kV or − 8 kV, when the generator was operated 3 cm from the epidermal tissue surface with a helium flow rate of 15 L/min. Exposing the injected flank skin for 10 min resulted in a rise of 37.3-fold for a plasma created with + 8 kV and 27.1-fold for a plasma created with − 8 kV. When using this treatment time with 50, 100, or 200 μg of a luciferase expressing plasmid, it was found that 100 μg resulted in the highest peak luminescence.Bioelectrochemistry 10/2014; 103. DOI:10.1016/j.bioelechem.2014.09.003 · 3.87 Impact Factor