title: Polyethylenimine-based polyplex delivery of self-replicating RNA vaccines.
abstract: Self-amplifying replicon RNA (RepRNA) are large molecules (12-14 kb); their self-replication amplifies mRNA template numbers, affording several rounds of antigen production, effectively increasing vaccine antigen payloads. Their sensitivity to RNase-sensitivity and inefficient uptake by dendritic cells (DCs) - absolute requirements for vaccine design - were tackled by condensing RepRNA into synthetic, nanoparticulate, polyethylenimine (PEI)-polyplex delivery vehicles. Polyplex-delivery formulations for small RNA molecules cannot be transferred to RepRNA due to its greater size and complexity; the N:P charge ratio and impact of RepRNA folding would influence polyplex condensation, post-delivery decompaction and the cytosolic release essential for RepRNA translation. Polyplex-formulations proved successful for delivery of RepRNA encoding influenza virus hemagglutinin and nucleocapsid to DCs. Cytosolic translocation was facilitated, leading to RepRNA translation. This efficacy was confirmed in vivo, inducing both humoral and cellular immune responses. Accordingly, this paper describes the first PEI-polyplexes providing efficient delivery of the complex and large, self-amplifying RepRNA vaccines.
  
  
  BACKGROUND
  The use of self-amplifying replicon RNA (RepRNA) to increase vaccine antigen payloads can potentially be useful in effective vaccine design. Nonetheless, its use is limited by the degradation during the uptake process. Here, the authors attempted to solve this problem by packaging RepRNA using polyethylenimine (PEI)-polyplex delivery vehicles. The efficacy was confirmed in vivo by the appropriate humoral and cellular immune responses. This novel delivery method may prove to be very useful for future vaccine design.
authors.affiliation: Institute of Virology and Immunology (IVI), Mittelhäusern, Switzerland. Electronic address: thomas.demoulins@ivi.admin.ch.
authors.forename: Thomas
authors.initials: T
authors.lastname: Démoulins
authors.affiliation: Institute of Virology and Immunology (IVI), Mittelhäusern, Switzerland.
authors.forename: Panagiota
authors.initials: P
authors.lastname: Milona
authors.affiliation: Institute of Virology and Immunology (IVI), Mittelhäusern, Switzerland.
authors.forename: Pavlos C
authors.initials: PC
authors.lastname: Englezou
authors.affiliation: Helmholtz Center for Infection Research Braunschweig (HZI), Department of Vaccinology and Applied Microbiology, Braunschweig, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ebensen
authors.affiliation: Helmholtz Center for Infection Research Braunschweig (HZI), Department of Vaccinology and Applied Microbiology, Braunschweig, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Schulze
authors.affiliation: Institute of Virology and Immunology (IVI), Mittelhäusern, Switzerland.
authors.forename: Rolf
authors.initials: R
authors.lastname: Suter
authors.affiliation: Centre de Biophysique Moléculaire, CNRS UPR4301, Inserm and Université d'Orléans, Orléans, France.
authors.forename: Chantal
authors.initials: C
authors.lastname: Pichon
authors.affiliation: Centre de Biophysique Moléculaire, CNRS UPR4301, Inserm and Université d'Orléans, Orléans, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Midoux
authors.affiliation: Helmholtz Center for Infection Research Braunschweig (HZI), Department of Vaccinology and Applied Microbiology, Braunschweig, Germany.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Guzmán
authors.affiliation: Institute of Virology and Immunology (IVI), Mittelhäusern, Switzerland.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Ruggli
authors.affiliation: Institute of Virology and Immunology (IVI), Mittelhäusern, Switzerland.
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: McCullough
mesh_terms: D000818:Animals; D000941:Antigens / Q000235:genetics* / Q000276:immunology; D002460:Cell Line; D003713:Dendritic Cells / Q000276:immunology; D007111:Immunity, Cellular; D056724:Immunity, Humoral; D008807:Mice, Inbred BALB C; D011094:Polyethyleneimine / Q000737:chemistry*; D014176:Protein Biosynthesis; D012313:RNA / Q000008:administration & dosage* / Q000235:genetics* / Q000276:immunology / Q000493:pharmacokinetics; D012093:Replicon; D013552:Swine; D014612:Vaccines / Q000008:administration & dosage* / Q000235:genetics* / Q000276:immunology / Q000493:pharmacokinetics
chemical_list: D000941:Antigens; D014612:Vaccines; D012313:RNA; D011094:Polyethyleneimine
keywords: Adjuvant; Blood dendritic cells; Humoral and cellular immunity; Influenza vaccines; Intracellular delivery; Polyplexes; Replicon-RNA; Self-replicating vaccine