title: Characterization of a Par j 1/Par j 2 mutant hybrid with reduced allergenicity for immunotherapy of Parietaria allergy.
abstract: BACKGROUND
  Parietaria pollen is one of the major cause of pollinosis in the southern Europe. Specific immunotherapy is the only treatment able to modify the natural outcome of the disease restoring a normal immunity against allergens.
  
  
  METHODS
  We designed a recombinant molecule (PjEDloop1) comprised of genetic-engineered variants of the major allergens of the Parietaria pollen (Par j 2/Par j 1). Purity and chemical-physical properties of the derivative were analysed by RP-HPLC chromatography and Photon Correlation Spectroscopy. Immunological activity was evaluated by means of Western blotting, ELISA inhibition and PBMC proliferation assay in 10 Parietaria allergic patients. Basophil activation was studied in six subjects. The immunogenicity of the hybrid was studied looking at the immune responses induced in a mouse model of sensitization.
  
  
  RESULTS
  The PjEDloop1 hybrid was produced as a purified recombinant protein with high stability in solution. Western blot, ELISA inhibition and basophil activation test showed that the PjEDloop1 displays a remarkable reduced IgE binding and anaphylactic activity. CD3 reactivity was conserved in all patients. Mice immunization with the rPjEDloop1 induced antibodies and T cell responses comparable to that obtained by the wild type allergens. Such antibodies shared the specificities to rPar j 1 and rPar j 2 with human IgE antibodies.
  
  
  CONCLUSIONS
  Our results demonstrated that a mutant hybrid expressing genetically engineered forms of the major P. judaica allergens displayed reduced allergenicity and retained T cell reactivity for the induction of protective antibodies in vaccination approaches for the treatment of Parietaria pollinosis.
authors.affiliation: Istituto di Biomedicina ed Immunologia Molecolare, Palermo, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Bonura
authors.forename: R
authors.initials: R
authors.lastname: Passantino
authors.forename: M A
authors.initials: MA
authors.lastname: Costa
authors.forename: G
authors.initials: G
authors.lastname: Montana
authors.forename: M
authors.initials: M
authors.lastname: Melis
authors.forename: M Luisa
authors.initials: ML
authors.lastname: Bondì
authors.forename: C
authors.initials: C
authors.lastname: Butteroni
authors.forename: B
authors.initials: B
authors.lastname: Barletta
authors.forename: S
authors.initials: S
authors.lastname: Corinti
authors.forename: G
authors.initials: G
authors.lastname: Di Felice
authors.forename: P
authors.initials: P
authors.lastname: Colombo
mesh_terms: D000485:Allergens / Q000276:immunology*; D000818:Animals; D052179:Antigens, Plant; D015153:Blotting, Western; D002851:Chromatography, High Pressure Liquid; D003888:Desensitization, Immunologic / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D005818:Genetic Engineering / Q000379:methods; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D016297:Mutagenesis, Site-Directed; D032403:Parietaria / Q000276:immunology*; D010940:Plant Proteins / Q000276:immunology*; D011994:Recombinant Proteins / Q000138:chemical synthesis / Q000276:immunology; D006255:Rhinitis, Allergic, Seasonal / Q000628:therapy
chemical_list: D000485:Allergens; D052179:Antigens, Plant; C105336:PMAI protein, Parietaria judaica; C103299:Par j 2.0101; D010940:Plant Proteins; D011994:Recombinant Proteins