title: The 2S albumin allergens of Arachis hypogaea, Ara h 2 and Ara h 6, are the major elicitors of anaphylaxis and can effectively desensitize peanut-allergic mice.
abstract: BACKGROUND
  Ara h 2 and Ara h 6, co-purified together in a 13-25 kD fraction (Ara h 2/6; 20 kD fraction) on gel filtration chromatography, account for the majority of effector activity in a crude peanut extract (CPE) when assayed with RBL SX-38 cells sensitized with IgE from human peanut allergic sera.
  
  
  OBJECTIVE
  To determine if Ara h 2/6 are the primary peanut allergens responsible for allergic reactions in vivo and to determine if Ara h 2/6 would be sufficient to prevent allergic reactions to a complete CPE.
  
  
  METHODS
  An oral sensitization mouse model of peanut allergy was used to assess the activity of Ara h 2/6 (20 kD) and CPE without the 20 kD fraction (CPE w/o 20 kD) for allergic provocation challenge and immunotherapy. The activity of these preparations was also tested in an assay of histamine release from human basophils in whole blood.
  
  
  RESULTS
  Compared with mice challenged with control CPE, mice challenged with CPE w/o 20 kD experienced reduced symptoms (P < 0.05) and a smaller decrease in body temperature (P < 0.01). Results with the basophil histamine release assay corroborated these findings (P < 0.01). The mouse model was also used to administer Ara h 2/6 (20 kD) in an immunotherapy protocol, in which peanut-allergic mice treated with the 20 kD fraction experienced significantly reduced symptoms, changes in body temperature, and mast cell protease (MMCP-1) release compared with placebo (P < 0.01 for all parameters). Importantly, immunotherapy with the 20 kD fraction was just as effective as treatment with CPE, whereas CPE w/o 20 kD was significantly less effective for higher dose peanut challenges.
  
  
  CONCLUSIONS
  Ara h 2/6 are the most potent peanut allergens in vivo and can be used to desensitize peanut-allergic mice. These results have potential implications for clinical research in the areas of diagnosis and immunotherapy for peanut allergy.
authors.affiliation: Department of Pediatric Allergy and Immunology, Duke University Medical Center, Durham, NC, USA.
authors.forename: M
authors.initials: M
authors.lastname: Kulis
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.forename: J
authors.initials: J
authors.lastname: Lew
authors.forename: Q
authors.initials: Q
authors.lastname: Wang
authors.forename: O P
authors.initials: OP
authors.lastname: Patel
authors.forename: Y
authors.initials: Y
authors.lastname: Zhuang
authors.forename: K S
authors.initials: KS
authors.lastname: Murray
authors.forename: M W
authors.initials: MW
authors.lastname: Duncan
authors.forename: H S
authors.initials: HS
authors.lastname: Porterfield
authors.forename: A
authors.initials: A
authors.lastname: W Burks
authors.forename: S C
authors.initials: SC
authors.lastname: Dreskin
mesh_terms: D055516:2S Albumins, Plant / Q000276:immunology / Q000494:pharmacology; D000707:Anaphylaxis / Q000276:immunology / Q000628:therapy*; D000818:Animals; D052179:Antigens, Plant / Q000276:immunology / Q000494:pharmacology; D010367:Arachis / Q000009:adverse effects* / Q000276:immunology; D001491:Basophils / Q000276:immunology; D003888:Desensitization, Immunologic; D004195:Disease Models, Animal; D005260:Female; D006023:Glycoproteins / Q000276:immunology / Q000494:pharmacology; D006632:Histamine / Q000276:immunology; D006801:Humans; D008297:Male; D051379:Mice; D021183:Peanut Hypersensitivity / Q000276:immunology / Q000628:therapy*; D053802:Tryptases / Q000276:immunology
chemical_list: D055516:2S Albumins, Plant; D052179:Antigens, Plant; C492737:Ara h 6 allergen, Arachis hypogaea; C078642:Ara h II protein, Arachis hypogaea; D006023:Glycoproteins; D006632:Histamine; D053802:Tryptases