AI Article Synopsis
- Bet v 1 is a significant allergen found in birch pollen, while its homologs in celery (Api g 1) and apple (Mal d 1) do not sensitize the immune system like Bet v 1 does.
- The study analyzed T-cell epitopes of Mal d 1 and compared its uptake and processing alongside Bet v 1 and Api g 1 using various biochemical methods.
- The results indicated that, unlike Bet v 1, both Api g 1 and Mal d 1 lack dominant T-cell epitopes, suggesting that the allergenic nature of Bet v 1 is linked to these T-cell-specific regions, rather than differences in how they are processed by immune cells.
Article Abstract
Background: Bet v 1 is the main sensitizing allergen in birch pollen. Like many other major allergens, it contains an immunodominant T cell-activating region (Bet v 1142-156). Api g 1, the Bet v 1 homolog in celery, lacks the ability to sensitize and is devoid of major T-cell epitopes.
Objective: We analyzed the T-cell epitopes of Mal d 1, the nonsensitizing Bet v 1 homolog in apple, and assessed possible differences in uptake and antigen processing of Bet v 1, Api g 1, and Mal d 1.
Methods: For epitope mapping, Mal d 1-specific T-cell lines were stimulated with overlapping synthetic 12-mer peptides. The surface binding, internalization, and intracellular degradation of Bet v 1, Api g 1, and Mal d 1 by antigen-presenting cells were compared by using flow cytometry. All proteins were digested with endolysosomal extracts, and the resulting peptides were identified by means of mass spectrometry. The binding of Bet v 1142-156 and the homologous region in Mal d 1 by HLA class II molecules was analyzed in silico.
Results: Like Api g 1, Mal d 1 lacked dominant T-cell epitopes. The degree of surface binding and the kinetics of uptake and endolysosomal degradation of Bet v 1, Api g 1, and Mal d 1 were comparable. Endolysosomal degradation of Bet v 1 and Mal d 1 resulted in very similar fragments. The Bet v 1142-156 and Mal d 1141-155 regions showed no striking difference in their binding affinities to the most frequent HLA-DR alleles.
Conclusion: The sensitizing activity of different Bet v 1 homologs correlates with the presence of immunodominant T-cell epitopes. However, the presence of Bet v 1142-156 is not conferred by differential antigen processing.
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|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4510200 | PMC |
| http://dx.doi.org/10.1016/j.jaci.2014.12.1928 | DOI Listing |
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Correlation of sensitizing capacity and T-cell recognition within the Bet v 1 family.
J Allergy Clin Immunol
July 2015
Christian Doppler Laboratory for Immunomodulation, Medical University of Vienna, Vienna, Austria; Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria. Electronic address:
Article Synopsis
- Bet v 1 is a significant allergen found in birch pollen, while its homologs in celery (Api g 1) and apple (Mal d 1) do not sensitize the immune system like Bet v 1 does.
- The study analyzed T-cell epitopes of Mal d 1 and compared its uptake and processing alongside Bet v 1 and Api g 1 using various biochemical methods.
- The results indicated that, unlike Bet v 1, both Api g 1 and Mal d 1 lack dominant T-cell epitopes, suggesting that the allergenic nature of Bet v 1 is linked to these T-cell-specific regions, rather than differences in how they are processed by immune cells.
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.
J Allergy Clin Immunol
July 2005
Department of Pathophysiology, Center of Physiology and Pathophysiology, Medical University of Vienna, Austria.
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.
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