title: In vivo electroporation enhances the immunogenicity of hepatitis C virus nonstructural 3/4A DNA by increased local DNA uptake, protein expression, inflammation, and infiltration of CD3+ T cells.
abstract: The mechanisms by which in vivo electroporation (EP) improves the potency of i.m. DNA vaccination were characterized by using the hepatitis C virus nonstructural (NS) 3/4A gene. Following a standard i.m. injection of DNA with or without in vivo EP, plasmid levels peaked immediately at the site of injection and decreased by 4 logs the first week. In vivo EP did not promote plasmid persistence and, depending on the dose, the plasmid was cleared or almost cleared after 60 days. In vivo imaging and immunohistochemistry revealed that protein expression was restricted to the injection site despite the detection of significant levels of plasmid in adjacent muscle groups. In vivo EP increased and prolonged NS3/4A protein expression levels as well as an increased infiltration of CD3+ T cells at the injection site. These factors most likely additively contributed to the enhanced and broadened priming of NS3/4A-specific Abs, CD4+ T cells, CD8+ T cells, and gamma-IFN production. The primed CD8+ responses were functional in vivo, resulting in elimination of hepatitis C virus NS3/4A-expressing liver cells in transiently transgenic mice. Collectively, the enhanced protein expression and inflammation at the injection site following in vivo EP contributed to the priming of in vivo functional immune responses. These localized effects most likely help to insure that the strength and duration of the responses are maintained when the vaccine is tested in larger animals, including rabbits and humans. Thus, the combined effects mediated by in vivo EP serves as a potent adjuvant for the NS3/4A-based DNA vaccine.
authors: Division of Clinical Microbiology, F68, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden.
authors: Gustaf
authors: G
authors: Ahlén
authors: Jonas
authors: J
authors: Söderholm
authors: Torunn
authors: T
authors: Tjelle
authors: Rune
authors: R
authors: Kjeken
authors: Lars
authors: L
authors: Frelin
authors: Urban
authors: U
authors: Höglund
authors: Pontus
authors: P
authors: Blomberg
authors: Michael
authors: M
authors: Fons
authors: Iacob
authors: I
authors: Mathiesen
authors: Matti
authors: M
authors: Sällberg
mesh_terms: D000818:Animals; D017252:CD3 Complex / Q000378:metabolism*; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism*; D018274:Electroporation; D005260:Female; D015967:Gene Expression Regulation, Viral; D016174:Hepacivirus / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D007249:Inflammation / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D007371:Interferon-gamma / Q000096:biosynthesis; D008099:Liver / Q000276:immunology / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010957:Plasmids / Q000235:genetics; D011817:Rabbits; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D018675:Toxicity Tests; D014611:Vaccination; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014761:Viral Hepatitis Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D017361:Viral Nonstructural Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology / Q000378:metabolism
chemical_list: D017252:CD3 Complex; D004279:DNA, Viral; D019444:Vaccines, DNA; D014761:Viral Hepatitis Vaccines; D017361:Viral Nonstructural Proteins; D007371:Interferon-gamma