Peanut oleosins associated with severe peanut allergy-importance of lipophilic allergens for comprehensive allergy diagnostics.
BACKGROUND
Peanut allergy is one of the most common and most severe food allergies in Western countries and its accurate diagnosis to prevent potential life-threatening allergic reactions is crucial. However, aqueous extracts used for routine diagnostic measurements are devoid of lipophilic allergens such as oleosins. We have recently succeeded in the isolation and purification of these unique proteins, and the present study evaluates their allergenic potential and clinical relevance.


OBJECTIVE
We sought to assess allergenicity and sensitization prevalence of oleosins obtained from both raw and in-shell roasted peanuts. In addition, we tested the utilization of natural and recombinant oleosins for allergy diagnostic purposes.


METHODS
Oleosin sensitization, prevalence, and impact of thermal processing were analyzed by immunoblot with sera from 52 peanut-allergic individuals displaying different clinical phenotypes. The application of natural and recombinant oleosins for allergy diagnostics was investigated by basophil activation test (BAT). IgE-binding epitopes were identified by oligopeptide microarray.


RESULTS
Sensitization to oleosins was observed exclusively in peanut-allergic subjects suffering from severe systemic reactions. IgE-binding capacity of oleosins derived from in-shell roasted peanuts was increased as shown by immunoblot analysis and BAT. Both natural and recombinant molecules can be used to identify oleosin-sensitized patients by BAT. A linear epitope of Ara h 15 was determined that displays high similarity to other seed-derived oleosins.


CONCLUSIONS
Oleosins are clinically relevant peanut allergens and most likely associated with severe allergic symptoms. In-shell roasting increases their allergenicity, which is consistent with the observation that most allergic reactions are in connection with roasted peanuts.
Division of Clinical and Molecular Allergology, Research Center Borstel, Priority Research Area Asthma and Allergy, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany.
Christian
C
Schwager
Division of Clinical and Molecular Allergology, Research Center Borstel, Priority Research Area Asthma and Allergy, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany.
Skadi
S
Kull
Core Facility Fluorescence Cytometry, Research Center Borstel, Borstel, Germany.
Jochen
J
Behrends
Division of Mucosal Immunology and Diagnostics, Research Center Borstel, Priority Research Area Asthma and Allergy, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany.
Niels
N
Röckendorf
Division of Clinical and Molecular Allergology, Research Center Borstel, Priority Research Area Asthma and Allergy, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany.
Frauke
F
Schocker
Division of Mucosal Immunology and Diagnostics, Research Center Borstel, Priority Research Area Asthma and Allergy, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany.
Andreas
A
Frey
Division of Clinical and Molecular Allergology, Research Center Borstel, Priority Research Area Asthma and Allergy, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany.
Arne
A
Homann
Division of Clinical and Molecular Allergology, Research Center Borstel, Priority Research Area Asthma and Allergy, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany.
Wolf-Meinhard
WM
Becker
Division of Clinical and Molecular Allergology, Research Center Borstel, Priority Research Area Asthma and Allergy, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany; Interdisciplinary Allergy Outpatient Clinic, Department of Internal Medicine, University of Luebeck, Luebeck, Germany. Electronic address: ujappe@fz-borstel.de.
Uta
U
Jappe
D000293:Adolescent; D000328:Adult; D000368:Aged; D000485:Allergens / Q000276:immunology / Q000378:metabolism*; D052179:Antigens, Plant / Q000276:immunology / Q000378:metabolism*; D010367:Arachis / Q000276:immunology; D002648:Child; D018604:Epitope Mapping; D018985:Epitopes, B-Lymphocyte / Q000378:metabolism; D005260:Female; D005858:Germany; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism; D008074:Lipoproteins / Q000276:immunology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D021183:Peanut Hypersensitivity / Q000453:epidemiology / Q000276:immunology*; D010455:Peptides / Q000378:metabolism*; D015995:Prevalence; D055815:Young Adult
D000485:Allergens; D052179:Antigens, Plant; D018985:Epitopes, B-Lymphocyte; D008074:Lipoproteins; D010455:Peptides; D007073:Immunoglobulin E
Ara h 10; Ara h 11; Ara h 14; Ara h 15; BAT; Peanut allergy; epitope mapping; lipophilic allergens; oleosins; roasting