IDENTIFICATION OF THE MAJOR WATER SALT INSOLUBLE WHEAT PROTEINS INVOLVED IN CEREAL HYPERSENSITIVITY/

Background Several studies have investigated water/salt soluble protei ns which comprise 50% of the proteins in wheat. The remaining 50% of w heat proteins, are water/salt insoluble proteins of which there is lim ited information on their role in cereal hypersensitivity. Objectives To investigate the allergenicity of the water/salt insoluble gliadin a nd glutenin proteins (prolamins). Methods RAST, electrophoresis and We stern blotting were used to identify water/salt insoluble wheat allerg ens. Competitive RAST inhibition was conducted to investigate crossrea ctivity between prolamins and water/salt soluble wheat proteins. Resul ts Specific IgE to alpha-gliadin and to total glutenins were detected in all sera. IgE to beta-, gamma-, fast omega-, and slow omega-gliadin were present in lower numbers of sera. Prolamin allergens of 90-11 kD a were identified by immunoblotting. Water/salt soluble proteins cross reacted with alpha-gliadin and total glutenins. Conclusions Individual s who are hypersensitive to water/salt soluble wheat proteins produce specific IgE to water/salt insoluble wheat proteins. Western blotting has shown that gliadins, glutenins and proteins with similar molecular weights as the endogenous water/salt soluble wheat enzyme inhibitors are important allergens. Alpha and fast omega- are the most allergenic gliadins. The water/salt insoluble proteins share cross-reacting epit opes with water/salt soluble proteins. These data show that the number s of proteins involved in the development of cereal hypersensitivity i s greater than previously believed and that the development of specifi c IgE to alpha-gliadin may in part depend on the presence of crossreac ting antibodies to water/salt soluble flour allergens.