title: Improvement of DNA vaccine immunogenicity by a dual antigen expression system.
abstract: This study examined whether increased antigen expression resulted in enhanced antigen-specific immune responses in the context of DNA vaccines. To increase antigen expression, two copies of antigen expression cassettes were arranged in a plasmid pDX. BALB/c mice were intramuscularly immunized with various constructs that express influenza antigens and analysed for DNA-raised immunity. The plasmid pDX that expresses two copies of the antigen gene induced stronger antigen-specific immune responses than the plasmid pGA which expresses single antigen gene. To explore the in vivo transgene expression by pDX and pGA, luciferase activity was measured in the muscles transduced with luciferase expression plasmids. The pDX expressing two copies of luciferase induced the highest luciferase activity, which corresponded to the results from vaccination. We concluded that increasing the number of antigen expression cassettes in a vaccine construct improved antigen expression in the transduced tissue, which induced stronger DNA-raised immune responses.
authors.affiliation: Department of Bioregulation, Leprosy Research Center, National Institute of Infectious Diseases, 4-2-1 Aoba-cho, Higashimurayama, Tokyo 189-0002, Japan. ssasaki@nih.go.jp
authors.forename: Shin
authors.initials: S
authors.lastname: Sasaki
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Takeshita
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Oikawa
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Kojima
authors.forename: Ke-Qin
authors.initials: KQ
authors.lastname: Xin
authors.forename: Kenji
authors.initials: K
authors.lastname: Okuda
authors.forename: Norihisa
authors.initials: N
authors.lastname: Ishii
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D000956:Antigens, Viral / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D005260:Female; D015870:Gene Expression; D017930:Genes, Reporter / Q000235:genetics; D005822:Genetic Vectors; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics / Q000276:immunology; D007273:Injections, Intramuscular; D007371:Interferon-gamma / Q000276:immunology; D015847:Interleukin-4 / Q000276:immunology; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009698:Nucleoproteins / Q000235:genetics / Q000276:immunology; D009975:Orthomyxoviridae / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic; D014161:Transduction, Genetic; D019076:Transgenes / Q000235:genetics; D014611:Vaccination; D019444:Vaccines, DNA / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D009698:Nucleoproteins; D019444:Vaccines, DNA; D015847:Interleukin-4; D007371:Interferon-gamma; D008156:Luciferases