Evaluation of Allergenicity on a ω-5 Gliadin-Deficient Cultivar in Wheat-Dependent Exercise-Induced Anaphylaxis

Purpose: ω-5 gliadin is the major allergen that causes wheat-dependent exercise-induced anaphylaxis (WDEIA). Recently, a missing mutant wheat cultivar at IB chromosome Glu-B3 and closely linked Gli-B1 loci was bred. This cultivar (ω5D) has a deficiency in ω-5 and γ-gliadins as well as some low-molecular-weight glutenins. We evaluated specific immunoglobulin E (sIgE) reactivity of the ω5D in WDEIA patients compared to wild-type cultivar. Methods: Serum samples from 14 WDEIA and 7 classic wheat allergy patients were used to compare the allergenicity of ω5D and wild-type cultivars using immunoglobulin E immunoblotting, enzyme-linked immunosorbent assay (ELISA), and ImmunoCAP inhibition assays. Results: Immunoblotting revealed that ω5D extracts had less sIgE binding to gliadins and glutenins in WDEIA sera than wild-type extracts. Immunoblot inhibition assay for gliadin sIgE reactivity also showed that ω5D gliadins had less allergenicity than wild-type gliadins. ELISA inhibition assay showed stronger allergenicity of gliadins than glutenins, although they had cross-reactivity. This assay also showed that the 50% inhibitory concentrations (IC50) of ω5D extracts against gliadin- or glutenin-sIgE reactivity were approximately 4-fold higher in WDEIA patients than those of wild-type extracts. The inhibition capacity of ω5D gliadins against recombinant ω-5 gliadin-sIgE reactivity was also lower in WDEIA patients than that of wild-type. Conclusions: The allergenicity of the ω5D cultivar is markedly lower for WDEIA patients in the sIgE inhibition tests. These results suggest that the ω5D cultivar may be a safe alternative for WDEIA patients.