IDENTIFICATION OF CROSS-REACTING WHEAT, RYE, BARLEY AND SOYA FLOUR ALLERGENS USING SERA FROM INDIVIDUALS WITH WHEAT-INDUCED ASTHMA

We have conducted radio allergosorbent test (PAST), competitive RAST i nhibition, sodium dodecyl sulfate polyacrylamide gel electrophoresis ( SDS-PAGE) and Western blotting using sera from patients with wheat-ind uced asthma to investigate the immunological relationship between whea t, rye, barley and soya, and to identify common proteins between these flours. PAST showed strong associations between the levels of specifi c IgE to wheat flour and those of rye and barley flour. Competitive PA ST inhibition showed that wheat, rye, barley and soya flours contained crossreacting proteins, in decreasing concentrations. Wheat, rye and barley flours had similar protein profiles on gel electrophoresis. Soy a flour contained a number of high molecular weight proteins not prese nt in the other cereals. Western blotting using sera from 21 wheat flo ur hypersensitive individuals identified a large number of allergens i n the different flours. Proteins of 69, 33, 26, 21 and 12 kDa were ide ntified as major wheat flour allergens. Rye flour proteins of 21 and 1 2 kDa, and barley flour proteins of 69, 52 and 10 kDa were the major a llergens identified by serum from wheat hypersensitive individuals. Th e major common protein of soya and wheat flour had a molecular weight of 21 kDa. The majority of crossreacting allergens identified between the different flours have molecular weights similar to those of known flour enzymes or enzyme inhibitors.