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Clinical & Experimental Allergy

Par j 1 and Par j 2, the major allergens from Parietaria judaica pollen, have similar immunoglobulin E epitopes

Authors


J. A. Asturias, Bial-Arístegui, Research and Development Department, Alameda Urquijo 27, 48008-Bilbao, Spain. E-mail: la.lp@bial.es

Summary

BackgroundParietaria judaica is the main cause of allergy in Mediterranean countries. The major allergens from P. judaica pollen, Par j 1 and Par j 2, have amino acid sequence identity of 45% and contain eight cysteine residues involved in disulphide bonds that compact the structure.

Objective The aim of the study was to identify IgE-binding epitopes on Par j 1 and Par j 2, the major allergens from P. judaica pollen and correlate them with the three-dimensional structure of the proteins.

Methods Overlapping peptides representing the complete length of Par j 1 and Par j 2 were synthesized on a cellulose-derivatized membrane. Sera from 17 P. judaica-allergenic patients were used to identify IgE-binding epitopes. Homology modelling of the three dimensional structure of both allergens was generated using the Swiss-Model software on the basis of previously reported crystal structures.

Results Five and eight IgE-binding epitopes were identified on Par j 1 and Par j 2 allergens, respectively. Both proteins belonged to the non-specific lipid transfer proteins (ns-LTP) family and therefore a three-dimensional model of both allergens was constructed on the basis of the maize ns-LTP crystal structure. Par j 1 and Par j 2 allergens have three similar allergenic epitopes with high homology and identical conformation.

Conclusion Three similar IgE-epitopes of major allergens from P. judaica have been described. They could be good candidates for designing of IgE haptens as therapeutic agents with reduced anaphylactic side-effects or for developing hypoallergenic variants of these major allergens.

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