Assessment of the sensitizing potential of processed peanut proteins in Brown Norway rats: roasting does not enhance allergenicity.

Stine Kroghsbo,Louise J Salt,Philip E Johnson,Neil M Rigby,Charlotte B Madsen,E N Clare Mills,Katrine L Bøgh,Karine Adel-Patient,Kottarappat N Dileepan

doi:10.1371/journal.pone.0096475

Stine Kroghsbo, Louise J Salt + Show 7 more

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https://doi.org/10.1371/journal.pone.0096475

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Abstract

BackgroundIgE-binding of process-modified foods or proteins is the most common method for examination of how food processing affects allergenicity of food allergens. How processing affects sensitization capacity is generally studied by administration of purified food proteins or food extracts and not allergens present in their natural food matrix.ObjectivesThe aim was to investigate if thermal processing increases sensitization potential of whole peanuts via the oral route. In parallel, the effect of heating on sensitization potential of the major peanut allergen Ara h 1 was assessed via the intraperitoneal route.MethodsSensitization potential of processed peanut products and Ara h 1 was examined in Brown Norway (BN) rats by oral administration of blanched or oil-roasted peanuts or peanut butter or by intraperitoneal immunization of purified native (N-), heated (H-) or heat glycated (G-)Ara h 1. Levels of specific IgG and IgE were determined by ELISA and IgE functionality was examined by rat basophilic leukemia (RBL) cell assay.ResultsIn rats dosed orally, roasted peanuts induced significant higher levels of specific IgE to NAra h 1 and 2 than blanched peanuts or peanut butter but with the lowest level of RBL degranulation. However, extract from roasted peanuts was found to be a superior elicitor of RBL degranulation. Process-modified Ara h 1 had similar sensitizing capacity as NAra h 1 but specific IgE reacted more readily with process-modified Ara h 1 than with native.ConclusionsPeanut products induce functional specific IgE when dosed orally to BN rats. Roasted peanuts do not have a higher sensitizing capacity than blanched peanuts. In spite of this, extract from roasted peanuts is a superior elicitor of RBL cell degranulation irrespectively of the peanut product used for sensitization. The results also suggest that new epitopes are formed or disclosed by heating Ara h 1 without glucose.

Highlights

Food allergy is an adverse reaction to an otherwise harmless food or food component that involves an abnormal response of the immune system to specific proteins in foods
Extract from roasted peanuts is a superior elicitor of rat basophilic leukemia (RBL) cell degranulation irrespectively of the peanut product used for sensitization
The results suggest that new epitopes are formed or disclosed by heating Ara h 1 without glucose

Summary

Introduction

Food allergy is an adverse reaction to an otherwise harmless food or food component that involves an abnormal response of the immune system to specific proteins in foods It is an allergenspecific immunologic response mediated by IgE. One of the major unanswered questions in food allergy research is what makes some foods and food proteins more allergenic than others Seeking such answer is difficult since the proteins involved in sensitizing or eliciting allergic reactions may have undergone extensive modifications during food processing or be presented within complex food matrices. Both food processing and structure of the food matrix may impact allergenicity of food allergens [1,2,3,4]. How processing affects sensitization capacity is generally studied by administration of purified food proteins or food extracts and not allergens present in their natural food matrix

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