title: Genetic polymorphisms and allergenicity of Blo t 5 in a house dust mite allergic Filipino population.
abstract: BACKGROUND
  Blo t 5, a major allergen from the house dust mite Blomia tropicalis had been identified as an important trigger of allergic diseases. Effects of sequence variations to the IgE binding activity of Blo t 5 remain unclear.
  
  
  OBJECTIVE
  The study determined gene polymorphisms of Blo t 5, expressed the recombinant Blo t 5 allergen in E. coli system and determined its IgE reactivity in house dust mite allergic Filipino patients.
  
  
  METHODS
  Gene polymorphism was determined using Polymerase Chain Reaction and DNA sequencing. Recombinant Blo t 5 was expressed as a GST-fusion protein in E. coli and purified by affinity chromatography. IgE-binding activity of 230 age-and sex-matched allergic and non-allergic subjects was subjected to Enzyme-linked Immunosorbent Assay and Western blot analysis.
  
  
  RESULTS
  Five polymorphic variants of Blo t 5 were identified with 26 DNA base and 12 amino acid substitutions thus implying a high degree of sequence diversity. Of the 115 cases, 68.70% and 59.13% showed reactivity to Blo t extract and rBlo t 5 respectively. Total and specific IgE levels of allergic and non-allergic subjects differ significantly (p< 0.0001).
  
  
  CONCLUSIONS
  Blo t 5 gene exhibits polymorphic variants with predicted amino acid sequences resulting to changes in its IgE epitopes. These polymorphisms may suggest variability of allergenic properties of Blo t 5. The incorporation of the Blo t 5 variants in the panel of diagnostic allergens and immunotherapy is highly recommended.
authors.affiliation: The Graduate School.|Natural Sciences Unit, College of Science.
authors.forename: Loida Recopuerto
authors.initials: LR
authors.lastname: Medina
authors.affiliation: Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Nat
authors.initials: N
authors.lastname: Malainual
authors.affiliation: The Graduate School.|Department of Biological Sciences, College of Science.|Research Center for the Natural and Applied Sciences, University of Santo Tomas, Manila, Philippines.
authors.forename: John Donnie
authors.initials: JD
authors.lastname: Ramos
mesh_terms: D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D000818:Animals; D002648:Child; D000939:Epitopes / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000175:diagnosis / Q000235:genetics*; D007073:Immunoglobulin E / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010679:Philippines; D011110:Polymorphism, Genetic; D011485:Protein Binding; D039981:Pyroglyphidae / Q000276:immunology; D055815:Young Adult
chemical_list: D000485:Allergens; D000939:Epitopes; C094701:allergen Blo t 5; D007073:Immunoglobulin E