Correlation of sensitizing capacity and T-cell recognition within the Bet v 1 family.
J Allergy Clin Immunol
; 136(1): 151-8, 2015 Jul.
Article
em En
| MEDLINE
| ID: mdl-25670010
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.Palavras-chave
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Base de dados:
MEDLINE
Assunto principal:
Linfócitos T
/
Epitopos de Linfócito T
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Antígenos de Plantas
/
Hipersensibilidade
Limite:
Humans
Idioma:
En
Revista:
J Allergy Clin Immunol
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
Áustria