INVOLVEMENT OF THE N-TERMINUS OF DER-P-2 IN IGE AND MONOCLONAL-ANTIBODY BINDING

The major house dust mite allergen Der p 2 was expressed as a recombin ant fusion protein in Escherichia coli either with glutathione-S-trans ferase as fusion partner or with a poly-histidine tag. Both recombinan t fusion proteins failed to react with 3/14 Der p 2-specific monoclona l antibodies (mAbs). When Der p 2 was expressed in yeast with one alan ine linked N-terminally to the allergen, no reactivity was observed. W hen expressed without any fusion partner, all 14 mAbs showed reactivit y. The addition of a single N-terminal alanine also disrupted an impor tant epitope for IgE. In RAST inhibitions, an average decrease in inhi bitory potency of 72+/-32% was observed (n = 16) with a maximum decrea se of 91%. These observations suggest that the N-terminus of Der p 2 i s involved in an important epitope for IgE that is disrupted by the ad dition of one single aminoacid. Recombinant Der p 2 molecules should t herefore preferably lack any fusion peptide.