The production of hypoallergenic wheat flour and the analysis of its allergy suppressive effects

A Narrative Mini Review on Current Status of Hypoallergenic Wheat Development for IgE-Mediated Wheat Allergy, Wheat-Dependent Exercise-Induced Anaphylaxis

Immunoglobulin E (IgE)-mediated food allergies to wheat that develop after school age typically shows a type of wheat-dependent exercise-induced anaphylaxis (WDEIA). At present, avoidance of wheat products or postprandial rest after ingesting wheat is recommended for patients with WDEIA, depending on the severity of the allergy symptoms. ω5-Gliadin has been identified as the major allergen in WDEIA. In addition, α/β-, γ-, and ω1,2-gliadins, high and low molecular weight-glutenins, and a few water-soluble wheat proteins have been identified as IgE-binding allergens in a small proportion of patients with IgE-mediated wheat allergies. A variety of approaches have been manufactured to develop hypoallergenic wheat products that can be consumed by patients with IgE-mediated wheat allergies. In order to analyze such approaches, and to contribute to the further improvement, this study outlined the current status of these hypoallergenic wheat productions, including wheat lines with a reduced allergenicity that are mostly constructed for the patients sensitized to ω5-gliadin, hypoallergenic wheat by enzymic degradation/ion exchanger deamidation, and hypoallergenic wheat by thioredoxin treatment. The wheat products obtained by these approaches significantly reduced the reactivity of Serum IgE in wheat-allergic patients. However, either these were not effective on some populations of the patients, or low-level IgE-reactivity to some allergens of the products was observed in the patients. These results highlight some of the difficulties faced in creating hypoallergenic wheat products or hypoallergenic wheat lines through either traditional breeding or biotechnology approaches in developing hypoallergenic wheat completely safe for all the patients allergic to wheat.

Safety Evaluation of Hypoallergenic Wheat Flour by Using a DNA Microarray

The effect of the consumption of hypoallergenic wheat flour (HWF) on the expression of a wide spectrum of genes was analyzed by using a DNA microarray. Gene expression profiles in the liver and intestines of rats fed on a diet composed mainly of HWF were compared with those of rats fed on a normal flour-based diet. Among the eight thousand transcripts represented on the GeneChip microarray, no more than 30 genes exhibited up- or down-regulation of two-fold or more after one week or two months of HWF consumption. No adverse effects were apparent. Up-regulation of some of the genes known to respond to the interferon-gamma signal was apparent in the one-week experiment, which may be related to possible oral immunotolerance resulting from HWF feeding. This DNA microarray technology presents an efficient method for evaluating the safety of foods.

In search of a tolerance-induction strategy for cow's milk allergies: significant reduction of beta-lactoglobulin allergenicity via transglutaminase/cysteine polymerization

OBJECTIVE

To explore the use of β-lactoglobulin polymerized using microbial transglutaminase and heating to identify whether protein polymerization could reduce in vivo allergenicity and maintain in vitro and ex vivo immunoreactivity for use in tolerance-induction protocols.

METHODS

Based on previous protocols applied in mice and children, we performed in vivo challenges (using a skin prick test) with native and polymerized β-lactoglobulin in adult patients with an IgE-mediated allergy to plactoglobulin. In vitro humoral immunoreactivity was analyzed using immunoblotting. Cell-mediated immunoreactivity was analyzed using ex vivo challenges with native and polymerized β-lactoglobulin and monitored by leukocyte adherence inhibition tests.

RESULTS

The skin tests demonstrated that there was a significant reduction in immediate cutaneous reactivity after polymerization. Polymerization did not decrease the immunoblotting detection of s-IgE specific to β-lactoglobulin. Cell-mediated immunoreactivity, as assessed by ex vivo challenges and leukocyte adherence inhibition tests, did not exhibit significant differences between leukocytes challenged with native versus polymerized β-lactoglobulin.

CONCLUSIONS

The polymerization of β-lactoglobulin decreased in vivo allergenicity and did not decrease in vitro humoral or ex vivo cell-mediated immunoreactivity. Therefore, we conclude that inducing polymerization using transglutaminase represents a promising technique to produce suitable molecules for the purpose of designing oral/ sublingual tolerance induction protocols for the treatment of allergies.

Identification of wheat gliadins as an allergen family related to baker's asthma

BACKGROUND

Flour is still one of the most common causes of occupational asthma worldwide. Thus far, little is known about the relevant allergens causing baker's asthma. Therefore the reliability of current diagnostic procedures is insufficient. Only few of the suspected causative wheat allergens have been hitherto characterized on the molecular level.

OBJECTIVE

The aim was to identify and characterize unknown wheat allergens related to baker's asthma to improve the reliability of diagnostic procedures.

METHODS

A wheat pJuFo cDNA phage display library was created and screened for IgE binding to wheat proteins with pooled sera from patients with baker's asthma. After identifying an alphabeta-gliadin, the frequency of sensitization was investigated by means of ELISA screening of 153 bakers' sera with the recombinant alphabeta-gliadin. Furthermore, the allergenicity of native total gliadin (alphabeta, gamma, omega) was analyzed by means of ImmunoCAP.

RESULTS

One cDNA clone was identified as an alphabeta-gliadin. Serum IgE antibodies to the recombinant allergen were found in 12% of bakers with occupational asthma. Of the asthmatic bakers, 33% showed sensitization to native total gliadin; 4% of them had negative results on routine IgE testing with wheat extract.

CONCLUSIONS

Gliadins represent a newly discovered family of inhalable allergens in baker's asthma. This finding demonstrates that water-insoluble proteins might also represent causative allergens.