title: Effect of roasting on the allergenicity of major peanut allergens Ara h 1 and Ara h 2/6: the necessity of degranulation assays.
abstract: BACKGROUND
  Peanuts are often consumed after roasting, a process that alters the three-dimensional structure of allergens and leads to Maillard modification. Such changes are likely to affect their allergenicity.
  
  
  OBJECTIVE
  We aimed to establish the effect of thermal treatment mimicking the roasting process on the allergenicity of Ara h 1 and a mix of 2S albumins from peanut (Ara h 2/6).
  
  
  METHODS
  Ara h 1 and Ara h 2/6 were purified from raw peanuts and heated in a dry form for 20 min at 145°C in the presence (R+g) or absence (R-g) of glucose, and soluble proteins were then extracted. Sera obtained from 12 well-characterized peanut-allergic patients were used to assess the IgE binding and degranulation capacities of the allergens.
  
  
  RESULTS
  Extensive heating at low moisture resulted in the hydrolysis of both Ara h 1 and Ara h 2/6. However, in contrast to Ara h 2/6, soluble R+g Ara h 1 formed large aggregates. Although the IgE-binding capacity of R+g and R-g Ara h 1 was decreased 9000- and 3.6-fold, respectively, compared with native Ara h 1, their capacity to elicit mediator release was increased. Conversely, both the IgE-binding capacity and the degranulation capacity of R-g Ara h 2/6 were 600-700-fold lower compared with the native form, although the presence of glucose during heating significantly moderated these losses.
  
  
  CONCLUSIONS
  Extensive heating reduced the degranulation capacity of Ara h 2/6 but significantly increased the degranulation capacity of Ara h 1. This observation can have important ramifications for component-resolved approaches for diagnosis and demonstrates the importance of investigating the degranulation capacity in addition to IgE reactivity when assessing the effects of food processing on the allergenicity of proteins.
authors.affiliation: Cell Biology and Immunology Group, Wageningen University and Research Centre, Wageningen, The Netherlands. Yvonne.Vissers@gmail.com
authors.forename: Y M
authors.initials: YM
authors.lastname: Vissers
authors.forename: M
authors.initials: M
authors.lastname: Iwan
authors.forename: K
authors.initials: K
authors.lastname: Adel-Patient
authors.forename: P
authors.initials: P
authors.lastname: Stahl Skov
authors.forename: N M
authors.initials: NM
authors.lastname: Rigby
authors.forename: P E
authors.initials: PE
authors.lastname: Johnson
authors.forename: P
authors.initials: P
authors.lastname: Mandrup Müller
authors.forename: L
authors.initials: L
authors.lastname: Przybylski-Nicaise
authors.forename: M
authors.initials: M
authors.lastname: Schaap
authors.forename: J
authors.initials: J
authors.lastname: Ruinemans-Koerts
authors.forename: A P H
authors.initials: AP
authors.lastname: Jansen
authors.forename: E N C
authors.initials: EN
authors.lastname: Mills
authors.forename: H F J
authors.initials: HF
authors.lastname: Savelkoul
authors.forename: H J
authors.initials: HJ
authors.lastname: Wichers
mesh_terms: D055516:2S Albumins, Plant / Q000737:chemistry / Q000276:immunology*; D000293:Adolescent; D000328:Adult; D000818:Animals; D052179:Antigens, Plant / Q000737:chemistry / Q000276:immunology*; D015549:Basophil Degranulation Test; D001491:Basophils / Q000276:immunology; D005260:Female; D006023:Glycoproteins / Q000737:chemistry / Q000276:immunology*; D006636:Histamine Release / Q000276:immunology; D006358:Hot Temperature; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D021183:Peanut Hypersensitivity / Q000276:immunology* / Q000517:prevention & control; D010940:Plant Proteins / Q000737:chemistry / Q000276:immunology*; D011489:Protein Denaturation / Q000528:radiation effects; D051381:Rats; D055815:Young Adult
chemical_list: D055516:2S Albumins, Plant; D052179:Antigens, Plant; C500889:Ara h 1 protein, Arachis hypogaea; C500890:Ara h 2 allergen, Arachis hypogaea; C492737:Ara h 6 allergen, Arachis hypogaea; D006023:Glycoproteins; D008565:Membrane Proteins; D010940:Plant Proteins; D007073:Immunoglobulin E