Naturally processed T cell-activating peptides of the major birch pollen allergen

J Allergy Clin Immunol. 2010 Mar;125(3):711-8, 718.e1-718.e2. doi: 10.1016/j.jaci.2009.10.052. Epub 2010 Feb 4.


Background: Although antigen processing and presentation of allergens to CD4(+)T lymphocytes are key events in the pathophysiology of allergic disorders, they still remain poorly understood.

Objective: To investigate allergen processing and presentation by dendritic cells using the major birch pollen allergen Bet v 1 as a model.

Methods: Endolysosomal extracts of dendritic cells derived from patients with birch pollen allergy were used to digest Bet v 1. Dendritic cells were pulsed with Bet v 1, and peptides were eluted from MHC class II molecules. Peptides obtained by either approach were sequenced by tandem mass spectrometry. Bet v 1-specific T-cell cultures were stimulated with HLA-DR-eluted Bet v 1-derived peptides. Bet v 1-specific T-cell lines were generated from each patient and analyzed for epitope recognition.

Results: A high proportion of Bet v 1 remained intact for a long period of endolysosomal degradation. The peptides that appeared early in the degradation process contained frequently recognized T-cell epitopes. Bet v 1-derived peptides eluted from MHC class II molecules corresponded to those generated by endolysosomal degradation, matched known T-cell epitopes, and showed T cell-activating capacity. The Bet v 1-specific T-cell line of each individual harbored T cells reactive with peptides located within the MHC class II-eluted Bet v 1-derived sequences demonstrating their occurrence in vivo.

Conclusion: We report for the first time how epitopes of allergens are generated and selected for presentation to T lymphocytes. The limited susceptibility of Bet v 1 to endolysosomal processing might contribute to its high allergenic potential.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigen Presentation / immunology*
  • Antigens, Plant / immunology
  • Antigens, Plant / metabolism*
  • Betula / immunology
  • CD4-Positive T-Lymphocytes / immunology*
  • Dendritic Cells / immunology*
  • Epitopes, T-Lymphocyte / immunology
  • Humans
  • Lymphocyte Activation / immunology*
  • Lysosomes / metabolism
  • Mass Spectrometry
  • Peptides / immunology
  • Peptides / metabolism
  • Pollen / immunology
  • Pollen / metabolism
  • Rhinitis, Allergic, Seasonal / immunology
  • Rhinitis, Allergic, Seasonal / metabolism*


  • Antigens, Plant
  • Epitopes, T-Lymphocyte
  • Peptides