Bet v 1142-156 is the dominant T-cell epitope of the major birch pollen allergen and important for cross-reactivity with Bet v 1-related food allergens.
BACKGROUND
Individuals with birch pollen allergy frequently experience hypersensitivity reactions to certain foods, primarily because of IgE antibodies specific for the major birch pollen allergen Bet v 1 that cross-react with homologous food allergens.


OBJECTIVE
We sought to characterize the major T-cell epitopes of Bet v 1 and to investigate their involvement in the cellular cross-reactivity with homologous food allergens.


METHODS
T-cell epitope mapping of Bet v 1 was performed by testing Bet v 1-specific T-cell lines derived from 57 individuals with birch pollen allergy, with overlapping peptides representing the entire allergen. T-cell lines and T-cell clones were stimulated with Bet v 1-related major allergens from apple (Mal d 1), cherry (Pru av 1), hazelnut (Cor a 1), celery (Api g 1), carrot (Dau c 1), and soybean (Gly m 4) and with peptides deduced from the C-terminal amino acid sequences of these molecules. Results Bet v 1 142-156 , positioned in the highly conserved C-terminal region of Bet v 1, was identified as the major T-cell epitope recognized by 61% of individuals. Most T lymphocytes specific for Bet v 1 142-156 were activated by one or more homologous food proteins or the respective peptides, as indicated by proliferation and cytokine production.


CONCLUSIONS
The major T-cell epitope of Bet v 1, Bet v 1 142-156 , plays an important role in the cellular cross-reactivity between this respiratory allergen and related food allergens. Thus T lymphocytes specific for Bet v 1 142-156 might be activated by various Bet v 1-related food allergens in vivo, even out of the pollen season.
Department of Pathophysiology, Center of Physiology and Pathophysiology, Medical University of Vienna, Austria.
Beatrice
B
Jahn-Schmid
Astrid
A
Radakovics
Dirk
D
Lüttkopf
Stephan
S
Scheurer
Stefan
S
Vieths
Christof
C
Ebner
Barbara
B
Bohle
D000485:Allergens / Q000737:chemistry* / Q000276:immunology; D029662:Betula / Q000276:immunology*; D003429:Cross Reactions; D018604:Epitope Mapping; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D005512:Food Hypersensitivity / Q000276:immunology*; D006801:Humans; D008969:Molecular Sequence Data; D011058:Pollen / Q000737:chemistry* / Q000276:immunology; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D013601:T-Lymphocytes / Q000276:immunology
D000485:Allergens; D018984:Epitopes, T-Lymphocyte