title: A plant protein signal sequence improved humoral immune response to HPV prophylactic and therapeutic DNA vaccines.
abstract: Signal sequences (ss) play a critical role in the sorting of nascent secretory and membrane proteins. This function has been conserved from bacteria through eukaryotes, although ss appear diverse in length and amino acid composition. Sorting of proteins is also critical to instruct antigens for a proper immunological response. Thus, a plant ss was used to drive Human Papillomavirus (HPV) model antigens into the human secretory pathway: the HPV16 E7 oncoprotein, its chimera with the coat protein (CP) of the Potato Virus X (PVX), the first 200 amino acids of the HPV16 minor capsid protein L2 (known to harbour cross-reacting epitopes) and its chimera with E7 gene. These genes were used to transfect HEK-293 cells and to immunize C57BL/6 mice. The ss-provided genes were expressed, and proteins detected by immunofluorescence and immunoblotting. Mouse immunization with DNA constructs carrying the ss elicited a strong humoral response against both E7 and L2 and a weak cell-mediated immunity. To our knowledge this is the first demonstration that a signal sequence derived from a plant can modulate the sorting of a heterologous protein in mammalian cells. This activity in mammalian cells may be responsible for the observed increased humoral response to DNA-based vaccines that are generally weak inducers of IgG response. This might open new perspectives in the design of DNA vaccines, especially to counteract infections where a strong humoral response is needed.
authors.affiliation: a ENEA - Italian National Agency for New Technologies, Energy and the Environment , Department of Sustainability, Laboratory of Biotechnologies , Rome , Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Massa
authors.affiliation: b Regina Elena National Cancer Institute HPV-UNIT , RIDAIT Dept , Rome , Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Paolini
authors.affiliation: b Regina Elena National Cancer Institute HPV-UNIT , RIDAIT Dept , Rome , Italy.
authors.forename: Gianfranca
authors.initials: G
authors.lastname: Curzio
authors.affiliation: c Department of Genetics , Federal University of Pernambuco, LEMTE , Pernambuco , Brazil.
authors.forename: Marcelo Nazario
authors.initials: MN
authors.lastname: Cordeiro
authors.affiliation: d University of Milan , Department of Pharmacological and Biomolecular Sciences , Milan , Italy.|e Laboratory of Biomedical Technologies , Rome , Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Illiano
authors.affiliation: a ENEA - Italian National Agency for New Technologies, Energy and the Environment , Department of Sustainability, Laboratory of Biotechnologies , Rome , Italy.
authors.forename: Olivia Costantina
authors.initials: OC
authors.lastname: Demurtas
authors.affiliation: e Laboratory of Biomedical Technologies , Rome , Italy.
authors.forename: Rosella
authors.initials: R
authors.lastname: Franconi
authors.affiliation: b Regina Elena National Cancer Institute HPV-UNIT , RIDAIT Dept , Rome , Italy.
authors.forename: Aldo
authors.initials: A
authors.lastname: Venuti
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D036022:Capsid Proteins / Q000235:genetics; D005260:Female; D007111:Immunity, Cellular; D056724:Immunity, Humoral; D008810:Mice, Inbred C57BL; D009856:Oncogene Proteins, Viral / Q000235:genetics; D050725:Papillomavirus E7 Proteins / Q000235:genetics; D030361:Papillomavirus Infections / Q000517:prevention & control*; D053918:Papillomavirus Vaccines / Q000235:genetics / Q000276:immunology*; D010940:Plant Proteins / Q000235:genetics*; D017863:Potexvirus / Q000235:genetics; D021382:Protein Sorting Signals; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D016896:Treatment Outcome; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology
chemical_list: D000914:Antibodies, Viral; D036022:Capsid Proteins; C063316:L2 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D053918:Papillomavirus Vaccines; D010940:Plant Proteins; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; D019444:Vaccines, DNA; D014614:Vaccines, Synthetic; C059731:oncogene protein E7, Human papillomavirus type 16
keywords: HPV; humoral immune response; infectious diseases; plant signal sequences; vaccines