IDENTIFICATION OF AN IMMUNODOMINANT IGE EPITOPE OF THE PARIETARIA-JUDAICA MAJOR ALLERGEN

Par j 1.0101 is one of the two major allergens of the Parietaria judai ca (Pj) pollen, and its three-dimensional structure was built by three -dimensional structural homology modeling, The resultant model was use d to identify putative IgE binding regions, Western blot analysis of g ene fragmentation products showed that the 1 to 30 region was capable of binding specific IgE from a pool of sera (n = 30) of patients aller gic to Pj pollen, Using the structural model as a guide, deletion and site directed mutagenesis of the 1 to 30 region was performed, and the amino acids involved in IgE binding were identified, In addition, a s ynthetic peptide covering the 1 to 30 region was capable of binding hu man IgE without triggering histamine release from basophils of Pj alle rgic patients (n = 6) and thus represents a haptenic molecule with pot ential use as an immunotolerant agent, This epitope is also present on the Par j 2.0101 major allergen representing a common IgE epitope, It is an immunodominant epitope, since it was capable of inhibiting 30% of all specific IgE against the Pj major allergens, and therefore, it might be a candidate for the future development of immunotherapeutics.