title: Immunization with a low-dose replicon DNA vaccine encoding Phl p 5 effectively prevents allergic sensitization.
abstract: BACKGROUND
  Replicase-based DNA vaccines stimulate T(H)1-biased immune responses at ultralow doses and induce self-removal of transfected cells through apoptosis. Both aspects are important requirements for efficient and safe DNA-based immunotherapy of type I allergies.
  
  
  OBJECTIVE
  A Sindbis virus replicon-based DNA vaccine encoding the major timothy grass pollen allergen Phl p 5 was evaluated for its antiallergic potential compared with a conventional DNA vaccine in a BALB/c mouse model of allergy.
  
  
  METHODS
  Mice were intradermally prevaccinated with plasmid DNA, followed by sensitization and intranasal allergen provocation with recombinant Phl p 5. In vitro proliferation and cytokine secretion was measured in splenocyte cultures. Distribution of IgG1, IgG2a, and IgE antibody subclasses was determined by means of ELISA. IgE-mediated degranulation was measured with the basophil release assay. Bronchoalveolar lavage fluid was analyzed for eosinophils, IL-4, IL-5, IL-13, and IFN-gamma. Mucus production, inflammatory infiltrates, and epithelial damage were determined in lung sections.
  
  
  RESULTS
  Both vaccines induced T(H)1-biased immune responses, resulting in suppression of functional IgE, reduction of eosinophilia in bronchoalveolar lavage fluid, and alleviation of lung pathology. However, immunization with the replicon DNA vaccine elicited these effects at a 100-fold lower dose compared with the conventional DNA vaccine.
  
  
  CONCLUSIONS
  The increased immunogenicity of replicon-based DNA vaccines allows for application of extremely low doses, thereby eliminating the concerns associated with conventional DNA vaccines, which have to be administered at milligram amounts to induce immune reactions in human subjects.
  
  
  CONCLUSIONS
  Their high safety profile makes replicon-based DNA vaccines promising candidates for treatment of type I allergies in the clinic.
authors.affiliation: Christian Doppler Laboratory for Allergy Diagnostic and Therapy, Department of Molecular Biology, University of Salzburg, Austria.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Gabler
authors.forename: Sandra
authors.initials: S
authors.lastname: Scheiblhofer
authors.forename: Kerstin
authors.initials: K
authors.lastname: Kern
authors.forename: Wolfgang W
authors.initials: WW
authors.lastname: Leitner
authors.forename: Angelika
authors.initials: A
authors.lastname: Stoecklinger
authors.forename: Cornelia
authors.initials: C
authors.lastname: Hauser-Kronberger
authors.forename: Beate
authors.initials: B
authors.lastname: Alinger
authors.forename: Berta
authors.initials: B
authors.lastname: Lechner
authors.forename: Monika
authors.initials: M
authors.lastname: Prinz
authors.forename: Susanne
authors.initials: S
authors.lastname: Vrtala
authors.forename: Rudolf
authors.initials: R
authors.lastname: Valenta
authors.forename: Josef
authors.initials: J
authors.lastname: Thalhamer
authors.forename: Richard
authors.initials: R
authors.lastname: Weiss
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D007271:Injections, Intradermal; D051379:Mice; D008807:Mice, Inbred BALB C; D010940:Plant Proteins / Q000008:administration & dosage / Q000235:genetics* / Q000276:immunology*; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics / Q000276:immunology; D012093:Replicon / Q000276:immunology*; D012130:Respiratory Hypersensitivity / Q000276:immunology* / Q000517:prevention & control*; D012845:Sindbis Virus / Q000201:enzymology / Q000235:genetics / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology*; D014765:Viral Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology
chemical_list: C076049:Phl p V protein, Phleum pratense; D010940:Plant Proteins; D019444:Vaccines, DNA; D014765:Viral Vaccines; D012324:RNA-Dependent RNA Polymerase