IGE ANTIBODIES TO RECOMBINANT POLLEN ALLERGENS (PHL-P-1, PHL-P-2, PHL-P-5, AND BET-V-2) ACCOUNT FOR A HIGH PERCENTAGE OF GRASS POLLEN-SPECIFIC IGE

Background: Pollen from different grass species are some of the most p otent elicitors of Type I allergy worldwide. The characterization of a ntigenic structures and IgE epitopes common to different grass species is relevant to define reagents for diagnosis and specific therapy of grass pollen allergy. Objective: The purpose of this study was to esti mate the percentage of IgE directed to common, cross-reactive, or both types of epitopes shared by recombinant pollen allergens (Phl p 1, Ph l p 2, Phl p 5, and Bet v 2) and natural pollen extracts from nine dif ferent monocots (Anthoxanthum odoratum, Avena sativa, Cynodon dactylon , Lolium perenne, Phragmites australis, Poa pratensis, Secale cereale, Triticum sativum, Zea mays) by using sera from different populations. Methods: Natural pollen extracts from nine different monocot species w ere characterized regarding their allergen contents by using specific antibodies and by IgE immunoblot inhibition with recombinant allergens . The percentage of grass pollen-specific IgE that was preabsorbed wit h a combination of recombinant timothy grass pollen allergens (Phl p 1 , Phl p 2, and Phl p 5) and recombinant birch profilin (Bet v 2) was d etermined by ELISA in sera from 193 European, American, and Asian subj ects. Results: IgE to recombinant pollen allergens accounted for a mea n 59% of grass pollen-specific IgE. A lower inhibition of IgE binding to certain natural extracts (C. dactylon and Z. mays) could be attribu ted to the absence of immunologically detectable group 5 and group 2 a llergens in these species. Conclusion: We define four recombinant poll en allergens that account for a substantial proportion of grass pollen -specific IgE. The recombinant pollen allergens characterized may repr esent candidates not only for diagnosis but also for patient-tailored immunotherapy of grass pollen allergy.