title: A hypoallergenic variant of Der p 1 as a candidate for mite allergy vaccines.
abstract: BACKGROUND
  Recombinant hypoallergens that display reduced allergenicity but retain T-cell reactivity represent promising candidates to improve the safety and efficacy of allergen-specific vaccines or immunotherapy.
  
  
  OBJECTIVE
  The current study reports the immunologic characterization of a hypoallergenic variant of the major mite allergen Der p 1.
  
  
  METHODS
  The recombinant proform of Der p 1 (ProDer p 1) was expressed in Escherichia coli (ProDer p 1 coli), purified and characterized at the level of its secondary structure, and IgE and T-cell reactivities. Moreover, the prophylactic potential of ProDer p 1 coli vaccinations was evaluated in a murine Der p 1 sensitization model.
  
  
  RESULTS
  After purification and refolding, ProDer p 1 coli remained aggregated with a higher beta-sheet content and altered Der p 1 conformational epitopes compared with the correctly folded monomeric ProDer p 1 produced in Chinese hamster ovary cells. Both ProDer p 1 forms were able to retain the Der p 1-specific T-cell reactivity but direct ELISA, competitive inhibition, and rat basophil leukemia assays clearly showed that ProDer p 1 coli displays a very weak IgE reactivity. Mice vaccinations with aggregated ProDer p 1 adjuvanted with alum induced a T(H)1-biased immune response that prevented the subsequent allergic response after Der p 1 sensitization and airway challenge with aerosolized mite extracts. Furthermore, ProDer p 1 coli treatment inhibited the development of airway eosinophilia and airway hyperresponsiveness to inhaled methacholine.
  
  
  CONCLUSIONS
  Aggregated forms of Der p 1 could represent hypoallergens suitable for the prevention of mite allergy.
authors.affiliation: Laboratoire d'Allergologie Expérimentale, Université Libre de Bruxelles, Institut de Biologie et de Médecine Moléculaires, Charleroi, Belgium.
authors.forename: David
authors.initials: D
authors.lastname: Walgraffe
authors.forename: Christel
authors.initials: C
authors.lastname: Mattéotti
authors.forename: Mohamed
authors.initials: M
authors.lastname: El Bakkoury
authors.forename: Lida
authors.initials: L
authors.lastname: Garcia
authors.forename: Céline
authors.initials: C
authors.lastname: Marchand
authors.forename: Dominique
authors.initials: D
authors.lastname: Bullens
authors.forename: Michel
authors.initials: M
authors.lastname: Vandenbranden
authors.forename: Alain
authors.initials: A
authors.lastname: Jacquet
mesh_terms: D000485:Allergens / Q000276:immunology*; D000818:Animals; D039741:Antigens, Dermatophagoides / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology; D060829:Arthropod Proteins; D001491:Basophils / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D016535:Bronchial Hyperreactivity / Q000276:immunology / Q000517:prevention & control; D016085:Bronchoconstrictor Agents / Q000494:pharmacology; D045744:Cell Line, Tumor; D003001:Cloning, Molecular; D003546:Cysteine Endopeptidases; D004195:Disease Models, Animal; D004802:Eosinophilia / Q000276:immunology / Q000517:prevention & control; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology / Q000517:prevention & control*; D007073:Immunoglobulin E / Q000097:blood; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology; D015848:Interleukin-5 / Q000096:biosynthesis / Q000276:immunology; D016210:Methacholine Chloride / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D039981:Pyroglyphidae / Q000276:immunology*; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D014612:Vaccines / Q000276:immunology*
chemical_list: D000485:Allergens; D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; D016085:Bronchoconstrictor Agents; D015848:Interleukin-5; D011994:Recombinant Proteins; D014612:Vaccines; D016210:Methacholine Chloride; D007073:Immunoglobulin E; D007371:Interferon-gamma; D003546:Cysteine Endopeptidases; C451162:Dermatophagoides pteronyssinus antigen p 1