title: Targeting human papillomavirus type 16 E7 to the endosomal/lysosomal compartment enhances the antitumor immunity of DNA vaccines against murine human papillomavirus type 16 E7-expressing tumors.
abstract: DNA vaccination is an attractive approach for tumor immunotherapy because of its stability and simplicity of delivery. Advances demonstrate that helper T cell responses play a critical role in initiating immune responses. The aim of the current study is to test whether targeting HPV-16 E7 to the endosomal/lysosomal compartment can enhance the potency of DNA vaccines. We linked the lysosome-associated membrane protein 1 (LAMP-1) to HPV-E7 to construct a chimeric DNA, Sig/E7/LAMP-1 DNA. For in vivo tumor prevention experiments, mice were vaccinated with E7 DNA or Sig/E7/LAMP-1 DNA via gene gun, followed by tumor challenge. For in vivo tumor regression experiments, mice were first challenged with tumor cells and then vaccinated with E7-DNA or Sig/E7/LAMP-1 DNA. Intracellular cytokine staining with flow cytometry analysis, cytotoxic T lymphocyte (CTL) assays, enzyme-linked immunoabsorbent assay (ELISA), and enzyme-linked immunospot (ELISPOT) assays were used for in vitro E7-specific immunological studies. In both tumor prevention and tumor regression assays, Sig/E7/LAMP-1 DNA generated greater antitumor immunity than did wild-type E7 DNA. In addition, mice vaccinated with Sig/E7/LAMP-1 DNA had greater numbers of E7-specific CD4+ helper T cells, higher E7-specific CTL activity, and greater numbers of CD8+ T cell precursors than did mice vaccinated with Sig/E7 or wild-type E7 DNA. Sig/E7 generated a stronger E7-specific antibody response than did Sig/E7/LAMP-1 or wild-type E7 DNA. Our results indicate that linkage of the antigen gene to an endosomal/lysosomal targeting signal may greatly enhance the potency of DNA vaccines.
authors.affiliation: Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA.
authors.forename: H
authors.initials: H
authors.lastname: Ji
authors.forename: T L
authors.initials: TL
authors.lastname: Wang
authors.forename: C H
authors.initials: CH
authors.lastname: Chen
authors.forename: S I
authors.initials: SI
authors.lastname: Pai
authors.forename: C F
authors.initials: CF
authors.lastname: Hung
authors.forename: K Y
authors.initials: KY
authors.lastname: Lin
authors.forename: R J
authors.initials: RJ
authors.lastname: Kurman
authors.forename: D M
authors.initials: DM
authors.lastname: Pardoll
authors.forename: T C
authors.initials: TC
authors.lastname: Wu
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000235:genetics; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology; D011992:Endosomes / Q000276:immunology; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D051907:Lysosomal Membrane Proteins; D008247:Lysosomes / Q000276:immunology; D008562:Membrane Glycoproteins / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D009374:Neoplasms, Experimental / Q000235:genetics / Q000276:immunology / Q000628:therapy* / Q000821:virology; D009856:Oncogene Proteins, Viral / Q000235:genetics* / Q000276:immunology; D050725:Papillomavirus E7 Proteins; D021382:Protein Sorting Signals / Q000235:genetics; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use*
chemical_list: D015703:Antigens, CD; D015395:Histocompatibility Antigens Class I; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D021382:Protein Sorting Signals; D019444:Vaccines, DNA; C059731:oncogene protein E7, Human papillomavirus type 16