WHEAT-FLOUR PEROXIDASE IS A PROMINENT ALLERGEN ASSOCIATED WITH BAKERSASTHMA

Background Putative wheat allergens with molecular sizes around 35 kDa have been repeatedly detected in immunoblots using sera from patients with baker's asthma. However, none of these allergens had been previo usly isolated. Objective To purify and characterize a major component of the 35 kDa allergenic band which seems to be present in flour from diploid, tetraploid (pasta) and hexaploid (bread) wheats. Methods Gel- filtration chromatography followed by RP-HPLC have allowed the purific ation of a new wheat allergen. Immunodetection with sera from allergic patients and with a specific serum for asparagine-linked complex glyc ans, as well as amino acid sequencing, were used to identify the isola ted protein. Results A 36 kDa allergen has been purified from wheat fl our. Its N-terminal and internal sequences, N-linked glycans, and enzy matic activity indicated that this allergen is a seed-specific peroxid ase. Sera from six out of 10 patients hypersensitive to wheat flour di splayed positive reactions when assayed against the purified dot-blott ed allergen. Conclusion Seed-specific peroxidases from cereals (flours ) seem to be important allergens in hypersensitive diseases associated with the manipulation of these plant materials. A new enzyme has thus been involved in IgE-mediated diseases.