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Human I g E against the major allergen B et v 1 – defining an epitope with limited cross‐reactivity between different PR ‐10 family proteins
Author(s) -
Levin M.,
Davies A. M.,
Liljekvist M.,
Carlsson F.,
Gould H. J.,
Sutton B. J.,
Ohlin M.
Publication year - 2014
Publication title -
clinical and experimental allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 154
eISSN - 1365-2222
pISSN - 0954-7894
DOI - 10.1111/cea.12230
Subject(s) - epitope , allergen , recombinant dna , monoclonal antibody , microbiology and biotechnology , linear epitope , chemistry , biology , antibody , immunology , biochemistry , gene , allergy
Summary Background The interaction between I g E and allergen is a key event at the initiation of an allergic response, and its characteristics have substantial effects on the clinical manifestation. Despite this, the molecular details of the interaction between human I g E and the major birch allergen B et v 1, one of the most potent tree allergens, still remain poorly investigated. Objective To isolate B et v 1‐specific human monoclonal I g E and characterize their interaction with the allergen. Methods Recombinant human I g E were isolated from a combinatorial antibody fragment library and their interaction with B et v 1 assessed using various immunological assays. The structure of one such I g E in the single‐chain fragment variable format was determined using X ‐ray crystallography. Results We present four novel B et v 1‐specific I g E , for one of which we solve the structure, all with their genetic origin in the IGHV 5 germline gene, and demonstrate that they target two non‐overlapping epitopes on the surface of B et v 1, thereby fulfilling the basic criteria for F cε RI cross‐linkage. We further define these epitopes and for one epitope pinpoint single amino acid residues important for the interaction with human I g E . This provides a potential explanation, at the molecular level, for the differences in recognition of isoforms of B et v 1 and other allergens in the PR ‐10 protein family displayed by I g E targeting this epitope. Finally, we present the first high‐resolution structure of a human allergen‐specific I g E fragment in the single‐chain fragment variable (sc F v) format. Conclusions and Clinical Relevance We here display the usefulness of allergen‐specific human monoclonal I g E as a tool in studies of the crucial molecular interaction taking place at the initiation of an allergic response. Such studies may aid us in development of better diagnostic tools and guide us in the development of new therapeutic compounds.