A chimeric IgE that mimics IgE from patients allergic to acid-hydrolyzed wheat proteins is a novel tool for in vitro allergenicity assessment of functionalized glutens

Abstract

BackgroundAcid-hydrolyzed wheat proteins (acid-HWPs) have been shown to provoke severe allergic reactions in Europe and Japan that are distinct from classical wheat allergies. Acid-HWPs were shown to contain neo-epitopes induced by the deamidation of gluten proteins. However, products with variable rates of deamidation can be found.ObjectivesIn this work, we studied the effect of the extent of wheat proteins deamidation on its allergenicity. A recombinant chimeric IgE was produced and compared to patients’ IgE for its capacity to assess the IgE-mediated triggering potential of acid-HWPs.MethodsSera from acid-HWP allergic patients were analyzed via ELISA and a functional basophil assay for their IgE reactivity to wheat proteins with different deamidation levels. A chimeric mouse/human IgE (chIgE-DG1) specific for the main neo-epitope, QPEEPFPE, involved in allergy to acid-HWPs was characterized with respect to its functionality and its reactivity compared to that of patients’ IgE.ResultsAcid-HWPs with medium (30%) and high (50–60%) deamidation levels displayed a markedly stronger IgE binding and capacity to activate basophils than those of samples with weak (15%) deamidation levels. The monoclonal chIgE-DG1 allowed basophil degranulation in the presence of deamidated wheat proteins. ChIgE-DG1 was found to mimic patients’ IgE reactivity and displayed the same ability to rank acid-HWP products in a degranulation assay.ConclusionIncreasing the deamidation level of products from 15% to 60% resulted in an approximately 2-fold increase in their antigenicity and a 100-fold increase in their eliciting potential. The chimeric ChIgE-DG1 may be a useful tool to evaluate functionalized glutens for their allergenic potential. By mimicking patient sera reactivity, chIgE-DG1 also provided data on the patients' IgE repertoire and on the functionality of certain repeated epitopes in gluten proteins.

Critical structural elements for the antigenicity of wheat allergen LTP1 (Tri a 14) revealed by site-directed mutagenesis

“…This was also the case of mAbs generated to Art v 3, which showed good overlap with patient IgE 41 . This sub-group of anti-Nat-LTP mAbs could enable generation of recombinant monoclonal IgE as substitutes mimicking patients reactivity 49 .…”

Detection of Sensitization Profiles with Cellular In Vitro Tests in Wheat Allergy Dependent on Augmentation Factors (WALDA)

“…HWPs, derived from gluten through chemical or enzymatic partial hydrolysis, exhibit increased solubility, as well as enhanced foaming and emulsifying abilities, making them frequently used in cosmetic products and foods [35]. Their functional properties and molecular composition vary depending on the treatment method [35,36], and hydrolysis may reveal or create new allergenic epitopes or influence allergen absorption [18,37,38]. HWPs in cosmetics are recognized as a potential cause of percutaneous sensitization leading to WALDA [19,37,39].…”

Creating hypo‐/nonallergenic wheat products using processing methods: Fact or fiction?

“…This product contained large sized proteins (40-50 kDa). Unfortunately, this product caused anaphylactic sensitization to wheat in a large number (>1000) of Japanese people (Chinuki & Morita, 2012;Chinuki et al, 2013;Fukutomi et al, 2011;Nakamura et al, 2013;Noguchi et al, 2019;Tranquet et al, 2017;Yokooji et al, 2013). An expert committee that reviewed the allergenicity of HWP and HWG concluded that these products are safe only when they are formulated to minimize peptide lengths greater than 30 amino acids (∼3.3 kDa; Burnett et al, 2018).…”