Multiple IgE recognition on the major allergen of the Parietaria pollen Par j 2

tThe interaction between IgE antibodies and allergens is a key event in triggering an allergic reaction. Thecharacterization of this region provides information of paramount importance for diagnosis and therapy.Par j 2 Lipid Transfer Protein is one of the most important allergens in southern Europe and a well-established marker of sensitization in Parietaria pollen allergy. The main aim of this study was to map theIgE binding regions of this allergen and to study the pattern of reactivity of individual Parietaria-allergicpatients. By means of gene fragmentation, six overlapping peptides were expressed in Escherichia coli, andtheir IgE binding activity was evaluated by immunoblotting in a cohort of 79 Parietaria-allergic patients.Our results showed that Pj-allergic patients display a heterogeneous pattern of IgE binding to the differentrecombinant fragments, and that patients reacted simultaneously against several protein domains spreadall the over the molecule, even in fragments which do not contain structural features resembling thenative allergen. Our results reveal the presence of a large number of linear and conformational epitopeson the Par j 2 sequence, which probably explains the high allergenic activity of this allergen.