Involvement of the N-Terminus of Der p 2 in IgE and Monoclonal Antibody Binding

Abstract

The major house dust mite allergen Der p 2 was expressed as a recombinant fusion protein in Escherichia coli either with glutathione-S-transferase as fusion partner or with a poly-histidine tag. Both recombinant fusion proteins failed to react with 3/14 Der p 2-specific monoclonal antibodies (mAbs). When Der p 2 was expressed in yeast with one alanine linked N-terminally to the allergen, no reactivity was observed. When expressed without any fusion partner, all 14 mAbs showed reactivity. The addition of a single N-terminal alanine also disrupted an important epitope for IgE. In RAST inhibitions, an average decrease in inhibitory potency of 72±32% was observed (n = 16) with a maximum decrease of 91%. These observations suggest that the N-terminus of Der p 2 is involved in an important epitope for IgE that is disrupted by the addition of one single aminoacid. Recombinant Der p 2 molecules should therefore preferably lack any fusion peptide.