Expressed sequence tags analysis of major allergens producing dust mites and molecular characterization of their allergens

Abstract

Understanding of the underlying genes expressed in allergen producing dust mite, Dermatophagoides farinae was carried out via Expressed Sequence Tagging (EST) approach, and the findings were compared to a parallel study of a tropical mite, Blomia tropicalis. House keeping genes and structural proteins are abundantly identified in the EST collections. 4-6% of the ESTs encode for >20 distinct allergen homologues identified from various sources. 20 allergen homologues including isoforms were expressed in Escherichia coli and immuno-assayed with 97 allergic sera. Group 2-3, 5-7, 10, 13 and Mag 1 allergens either binds IgE frequently or strongly or both. The rest of the proteins were sometimes unique to an individual serum and those newly identified in mite species could be potential pan allergens. Deletion studies and molecular modeling suggest the presence of immuno-dominant epitope(s) among group 13 allergens. Characterizations of the allergenic components in mites are essential for effective allergy diagnosis and immunotherapy.