title: In search of a vaccine for mouse allergy: significant reduction of Mus m 1 allergenicity by structure-guided single-point mutations.
abstract: BACKGROUND
  Mouse urinary proteins are relevant allergens from mice urine. We used the recombinant protein Mus m 1 as an allergen model to identify if, by altering Mus m 1 architecture via single-point mutations, we could effectively modify its allergenicity.
  
  
  METHODS
  Based on structural considerations, we synthesized two single-point mutants, Mus m 1-Y120A and Mus m 1-Y120F, which were expected to harbor large structural alterations. Circular dichroism and fluorescence analysis showed significant conformational rearrangements of the aromatic side chains in the internal cavity of Mus m 1-Y120A when compared to Mus m 1-Y120F and Mus m 1. Evaluation of the allergenic potential of the recombinant molecules was performed in vitro with both immunochemical approaches and assays based on the measurement of basophil degranulation. Moreover, to assess the integrity of the T cell epitopes and as an in vitro measure of immunogenicity, we tested the reactivity of T lymphocytes from subjects allergic to mouse urine against proteins and synthetic peptides encompassing the immunodominant linear epitope containing the mutation.
  
  
  RESULTS
  We found that the selected point mutation was able to modulate the protein allergenicity, and to severely impair the recognition of Mus m 1 by IgE, while T cell reactivity was fully maintained.
  
  
  CONCLUSIONS
  In silico predicted, minimum selected structural modifications allowed to design one protein with reduced allergenicity and preserved immunogenicity. Structurally guided mutations can direct the design of proteins with reduced allergenicity which can be used as vaccines for a safer and more effective immunotherapy of allergic disorders.
authors: Department of Experimental Medicine, University of Parma, Parma, Italy.
authors: Elena
authors: E
authors: Ferrari
authors: Daniela
authors: D
authors: Breda
authors: Renato
authors: R
authors: Longhi
authors: Luca
authors: L
authors: Vangelista
authors: Clóvis R
authors: CR
authors: Nakaie
authors: Lisa
authors: L
authors: Elviri
authors: Emanuela
authors: E
authors: Casali
authors: Thelma A
authors: TA
authors: Pertinhez
authors: Alberto
authors: A
authors: Spisni
authors: Samuele E
authors: SE
authors: Burastero
mesh_terms: D000328:Adult; D000485:Allergens / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D000818:Animals; D015549:Basophil Degranulation Test; D015153:Blotting, Western; D002942:Circular Dichroism; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D006801:Humans; D006967:Hypersensitivity / Q000175:diagnosis / Q000276:immunology*; D007073:Immunoglobulin E / Q000276:immunology*; D007167:Immunotherapy; D051379:Mice; D016297:Mutagenesis, Site-Directed; D017354:Point Mutation; D017433:Protein Structure, Secondary; D013050:Spectrometry, Fluorescence; D013601:T-Lymphocytes / Q000276:immunology*; D014614:Vaccines, Synthetic
chemical_list: D000485:Allergens; D018984:Epitopes, T-Lymphocyte; C518791:Mus m 1 allergen, Mus musculus; D014614:Vaccines, Synthetic; D007073:Immunoglobulin E