Cutaneous Transfection and Immune Responses to Intradermal Nucleic Acid Vaccination Are Significantly Enhanced by in Vivo Electropermeabilization

Abstract

Naked DNA injection with electropermeabilization (EP) is a promising method for nucleic acid vaccination (NAV) and in vivo gene therapy. Skin is an ideal target for NAV due to ease of administration and the accessibility of large numbers of antigen-presenting cells within the tissue. This study demonstrates that in vivo skin EP may be used to increase transgene expression up to an average of 83-fold relative to naked DNA injection (50 microg DNA per dose, P < 0.005). Transfected cells were principally located in dermis and included adipocytes, fibroblasts, endothelial cells, and numerous mononuclear cells with dendritic processes in a porcine model. Transfected cells were also observed in lymph nodes draining electropermeabilized sites. A HBV sAg-coding plasmid was used to test skin EP-mediated NAV in a murine model. Analysis of humoral immune responses including immunoglobulin subclass profiles revealed strong enhancement of EP-mediated NAV relative to naked DNA injection, with a Th1-dominant, mixed-response pattern compared to immunization with HBV sAg protein that was exclusively Th2 (P = 0.02). Applications for these findings include NAV-based modulation of immune responses to pathogens, allergens, and tumor-associated antigens and the modification of tolerance.

Electroporative transfection with KGF-1 DNA improves wound healing in a diabetic mouse model

“…10 In the present study, we utilized electroporation to improve transfection efficiency so that a single dosing regimen could be utilized and a much smaller application of DNA would be required. Drabick et al 16 demonstrated that electroporation enhances gene uptake into various cells in the cutaneous layer in mouse and pig. We utilized the skin specific electroporation parameters that we identified in our earlier work.…”

“…It is believed that if the applied electrical field is of sufficient strength and intensity the dielectric index of the cell membrane is exceeded, causing transient pores to open in the lipid bilayer thereby increasing the permeability of the cells to large molecules. 16 We have demonstrated that by optimization of the electroporation parameters transfection efficiency can be improved in murine cutaneous wounds. 17 For the current study, we used the diabetic mouse BKS.Cg-m homozygous (Lepr db /Lepr db ) as a wound-healing model.…”

“…In this study all mice (32) were injected with DNA although only half 16 were electroporated. From Figure 5, it can be noted that at the early stages of the experiment (day 5) the wound sizes were not significantly different, however, at days 10 and 12 the wound areas of the electroporated group were more than 50% smaller than the nonelectroporated group indicating a positive healing effect in the presence of electroporation.…”

“…Electroporation has been shown to improve cellular uptake of DNA by more than 10-fold over injection alone, and has exhibited none of the safety concerns associated with viral gene delivery. 16 Electroporation is the application of an electrical field across a tissue or cell. It is believed that if the applied electrical field is of sufficient strength and intensity the dielectric index of the cell membrane is exceeded, causing transient pores to open in the lipid bilayer thereby increasing the permeability of the cells to large molecules.…”

Electro-gene therapy of collagen-induced arthritis by using an expression plasmid for the soluble p75 tumor necrosis factor receptor-Fc fusion protein

“…The studies on the application of electroporation-mediated gene transfer to larger animals are ongoing. 39,40 Recently, it has been reported that local gene transfer could result in a systemic therapeutic effect without systemic elevation of the therapeutic protein. 19,41 Further investigation on the mechanism responsible for these phenomena may help to develop the clinically relevant protocol for electroporation-based gene delivery strategy for the treatment of human RA.…”