Wheat allergy is a potentiallylife-threatening disease that affects millions of people around the world. Food processing has been shown to influence the allergenicity of wheat and other major foods. However, a comprehensive review evaluating whether or not food processing can be used to develop hypo-/nonallergenic wheat products is unavailable. There were three objectives for this study: (1) to critically evaluate the evidence on the effect of fermentation, thermal processing, and enzyme or acid hydrolysis on wheat allergenicity so as to identify the potential for and challenges of using these methods to produce hypo-/nonallergenic wheat products; (2) to identify the molecular effects of food processing needed to create such products; and (3) to map the concept questions for future research and development to produce hypo-/nonallergenic wheat products. We performed literature research using PubMed and Google Scholar databases with various combinations of keywords to generate the data to accomplish these objectives. We found that: (1) food processing significantly modulates wheat allergenicity; while some methods can reduce or even abolish the allergenicity, others can create mega allergens; and (2) fermentation and enzymatic hydrolysis hold the most potential to create novel hypo-/nonallergenic wheat products; however, preclinical validation and human clinical trials are currently lacking. We also identify five specific research concepts to advance the research to enable the creation of hypo-/nonallergenic wheat products for application in food, medical, and cosmetic industries.

Wheat is a major food allergen per the regulatory bodies of various nations. Hypersensitivity reactions to wheat have been steadily increasing for reasons that are not completely understood. Wheat-allergy models typically use adjuvants to induce sensitization to wheat proteins followed by an intraperitoneal challenge to elicit anaphylaxis. Although these models are very useful, they lack the ability to reveal the intrinsic allergenicity potential of wheat. To improve the mouse model of wheat allergy, we tested the hypothesis that repeated skin application of salt-soluble protein extract (SSPE) from durum wheat will clinically sensitize the mice to oral anaphylaxis to SSPE. Balb/c mice were bred and maintained on a plant-protein-free diet and used in the experiments. Adult female mice were exposed to SSPE once a week for 9 weeks via a solution on intact skin. Sensitization was measured by SSPE-specific IgE (sIgE) antibody and total IgE (tIgE) levels. Oral anaphylaxis was quantified by hypothermic shock response (HSR), and mucosal mast cell response (MMCR) was quantified by measuring MMCP-1 after oral challenge. Using single mouse data, correlation analyses were performed to determine the relationship among the allergenicity readouts. Spleen cytokines were quantified using a protein microarray method. Our results show that (i) repeated skin exposures to SSPE elicited robust increases in the sIgE and tIgE levels; (ii) skin exposure to SSPE was sufficient to sensitize mice for oral anaphylaxis and MMCR; (iii) both HSR and MMCR showed a strong correlation with each other, as well as with sIgE, and a modest correlation with tIgE levels; (iv) selected Th2/Th17/Th1 cytokines were elevated in skin-sensitized mice; and (v) oral allergen-challenged mice showed selective elevation of IL-6 and a panel of chemokines compared to saline-challenged mice. Together, we report the development and characterization of a novel adjuvant-free wheat-allergy mouse model that uses skin sensitization without tape-stripping followed by oral elicitation of anaphylaxis. Furthermore, validation of quantifiable wheat allergenicity readouts makes this model particularly suitable as a pre-clinical testing tool to assess the intrinsic sensitization/oral-anaphylaxis elicitation potential of novel wheat proteins (e.g., processed wheat) and to develop hypo/non-allergenic wheat products.

Wheat allergies are potentially life-threatening because of the high risk of anaphylaxis. Wheats belong to four genotypes represented in thousands of lines and varieties. Monitoring changes to wheat allergens is critical to prevent inadvertent ntroduction of hyper-allergenic varieties via breeding. However, validated methods for this purpose are unavailable at present. As a proof-of-concept study, we tested the hypothesis that salt-soluble wheat allergens in our mouse model will be identical to those reported for humans. Groups of Balb/cJ mice were rendered allergic to durum wheat salt-soluble protein extract (SSPE). Using blood from allergic mice, a mini hyper-IgE plasma bank was created and used in optimizing an IgE Western blotting (IEWB) to identify IgE binding allergens. The LC-MS/MS was used to sequence the allergenic bands. An ancient Aegilops tauschii wheat was grown in our greenhouse and extracted SSPE. Using the optimized IEWB method followed by sequencing, the cross-reacting allergens in A. tauschii wheat were identified. Database analysis showed all but 2 of the durum wheat allergens and all A. tauschii wheat allergens identified in this model had been reported as human allergens. Thus, this model may be used to identify and monitor potential changes to salt-soluble wheat allergens caused by breeding.

Hypersensitivity reactions to wheat have reached significant levels of global public health concern for reasons that are incompletely understood. Einkorn wheat (Triticum monococcum, genome AA) is commercially available but is rarely consumed, whereas durum wheat (Triticum durum, genome AABB) is commonly used for pasta making. At present, most mouse models of wheat allergy are adjuvant-based, which fail to reveal the intrinsic allergenic potential of different wheat products. Here we compared einkorn and durum wheats in terms of their sensitizing and disease-eliciting capacities in an adjuvant-free mouse model of anaphylaxis induced by salt-soluble protein extract (SSPE). Balb/cJ female mice were sensitized transdermally with SSPE or saline for nine weeks. Later, systemic or oral anaphylactic reactions were elicited in these mice using SSPE via intraperitoneal or oral route, respectively. We did not observe major differences in sensitizing capacity as suggested by antibody responses (i.e., sIgE and tIgE levels) in SSPE-sensitized mice. However, SSPE from durum appears to be more potent than that from einkorn in eliciting systemic but not oral anaphylaxis as shown by hypothermic shock responses as well as mucosal mast cell degranulation. This is the first report on comparing the intrinsic allergenicity between tetraploid and diploid wheats in an adjuvant-free mouse model. This research was funded by: the United States Department of Agriculture (USDA)/National Institute of Food and Agriculture (NIFA); Hatch project MICL02486 (Accession Number: 1012322), Hatch project MICL01699; Agricultural and Food Research Initiative Competitive Program, grant number: 2018-67017-27876; and Project GREEEN (Michigan State University); R.J., was supported by the John Harvey Kellogg Graduate Assistantship and the Academic Achievement Graduate Assistantship from the Michigan State University.

Wheat is a major allergenic food capable of eliciting life-threatening anaphylaxis. Food allergies including wheat allergy are growing globally, and therefore warrant further investigation. While animal studies are being conducted to advance our understanding of wheat allergy, it is unknown whether female versus male mice differ in their allergic responses to wheat gluten. Here we tested the hypothesis that alcohol-soluble wheat gluten (ASWG) when applied over the skin will sensitize both female and male mice for oral hypothermia shock response in an adjuvant-free mouse model. Balb/cJ mice were produced and kept on a plant protein-free diet during this study. Groups of adult mice (n = 8–10) were exposed to durum wheat ASWG via the skin (once a week for nine weeks), without an adjuvant using our previously reported transdermal exposure (TDE) method. In females, TDE with the ASWG elicited a significant ASWG-specific IgE antibody response. However, in males, TDE with the ASWG did not elicit a significant ASWG-specific IgE antibody response. Oral challenge of ASWG, but not vehicle, elicited significant hypothermia shock response in ASWG skin-sensitized female mice. In contrast, no significant hypothermia shock response was observed in males upon oral challenge with ASWG or vehicle. These data demonstrate that female mice are more susceptible than males to develop an allergic response and oral anaphylaxis to ASWG in this model.