Western blot analysis of water-soluble wheat flour (Triticum vulgaris) allergens.

Water-soluble wheat flour allergens were analyzed using the western blot technique. The sera of 130 bakers (42 with wheat flour allergy, 88 without allergy) were analyzed for IgE, IgG, and IgG4 binding towards wheat flour allergens. Three major allergens with molecular weights of 47, 17, and 15 kD were identified (Tri v Bd 47, Tri v Bd 17, and Tri v Bd 15; IUIS allergen nomenclature) by their ability to bind IgE from approximately 50% of the allergic sera. The specificity of the IgG was mostly directed against three high molecular weight components (134, 122, and 98 kD). In contrast, IgE and IgG4 was found frequently against the major allergens. 40% of healthy donors versus 12% of the asthmatic bakers had no detectable IgG4 against wheat flour extract. The biological activity of the water-soluble wheat flour components has been shown by their ability to induce histamine release from basophil leukocytes obtained from patients with bakers' asthma. The release of histamine from basophil leukocytes significantly correlated with the presence of IgE antibodies against wheat flour components of 47, 17 and 15 kD. A regulatory role of wheat flour specific IgG4 in allergic diseases could not be evaluated by western blot analysis.