title: The House Dust Mite Major Allergen Der p 23 Displays O-Glycan-Independent IgE Reactivities but No Chitin-Binding Activity.
abstract: BACKGROUND
  The in-depth characterization of the recently identified house dust mite (HDM) major allergen Der p 23 requires the production of its recombinant counterpart because the natural allergen is poorly extractable from fecal pellets. This study aimed to provide a detailed physico-chemical characterization of recombinant Der p 23 (rDer p 23) as well as to investigate its IgE reactivity in a cohort of HDM-allergic patients from Thailand.
  
  
  METHODS
  Purified rDer p 23, secreted from recombinant Pichia pastoris, was characterized by mass spectrometry and circular dichroism analyses as well as for its chitin-binding activity. The IgE-binding frequency and allergenicity of Der p 23 were determined by ELISA and RBL-SX38 degranulation assays, respectively.
  
  
  RESULTS
  Purified intact rDer p 23 carried O-mannosylation and mainly adopted a random coil structure. Polyclonal antibodies to rDer p 23 can detect the corresponding natural allergen (nDer p 23) in aqueous fecal pellet extracts, suggesting that both forms of Der p 23 share common B-cell epitopes. Despite its homologies with chitin-binding proteins, both natural Der p 23 and rDer p 23 were unable to interact in vitro with chitin matrices. Of 222 Thai HDM-allergic patients tested, 54% displayed Der p 23-specific IgE responses. Finally, the allergenicity of rDer p 23 was confirmed by the degranulation of rat basophil leukemia cells.
  
  
  CONCLUSIONS
  Our findings highlighted important levels of Der p 23 sensitizations in Thailand. Our study clearly suggested that rDer p 23 is likely more appropriate for HDM allergy component-resolved diagnosis than HDM extracts.
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Medicine and Chula Vaccine Research Center, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Wai Tuck
authors.initials: WT
authors.lastname: Soh
authors.forename: Maxime
authors.initials: M
authors.lastname: Le Mignon
authors.forename: Narissara
authors.initials: N
authors.lastname: Suratannon
authors.forename: Pattraporn
authors.initials: P
authors.lastname: Satitsuksanoa
authors.forename: Pantipa
authors.initials: P
authors.lastname: Chatchatee
authors.forename: Jongkonnee
authors.initials: J
authors.lastname: Wongpiyaboron
authors.forename: Mukda
authors.initials: M
authors.lastname: Vangveravong
authors.forename: Ticha
authors.initials: T
authors.lastname: Rerkpattanapipat
authors.forename: Atik
authors.initials: A
authors.lastname: Sangasapaviliya
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Nony
authors.forename: Surapon
authors.initials: S
authors.lastname: Piboonpocanun
authors.forename: Kiat
authors.initials: K
authors.lastname: Ruxrungtham
authors.forename: Alain
authors.initials: A
authors.lastname: Jacquet
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D039741:Antigens, Dermatophagoides / Q000276:immunology*; D045744:Cell Line, Tumor; D002686:Chitin / Q000378:metabolism*; D002942:Circular Dichroism; D006031:Glycosylation; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology*; D008969:Molecular Sequence Data; D051381:Rats
chemical_list: D039741:Antigens, Dermatophagoides; D002686:Chitin; D007073:Immunoglobulin E