2S protein Ara h 7.0201 has unique epitopes compared to other Ara h 7 isoforms and is comparable to 2S proteins Ara h 2 and 6 in basophil degranulation capacity.
Clin Exp Allergy
; 48(7): 890-897, 2018 07.
Article
em En
| MEDLINE
| ID: mdl-29542223
ABSTRACT
BACKGROUND:
Screening for specific IgE against 2S albumin proteins Ara h 2 and 6 has good positive predictive value in diagnosing peanut allergy. From the third 2S member Ara h 7, 3 isoforms have been identified. Their allergenicity has not been elucidated.OBJECTIVE:
This study investigated the allergenicity of Ara h 7 isoforms compared to Ara h 2 and 6.METHODS:
Sensitization of 15 DBPCFC-confirmed peanut-allergic patients to recombinant Ara h 2.0201, Ara h 6.01 and isoforms of recombinant Ara h 7 was determined by IgE immunoblotting strips. A basophil activation test (BAT) was performed in 9 patients to determine IgE-cross-linking capacities of the allergens. Sensitivity to the allergens was tested in 5 patients who were sensitized to at least 1 Ara h 7 isoform, by a concentration range in the BAT. 3D prediction models and sequence alignments were used to visualize differences between isoforms and to predict allergenic epitope regions.RESULTS:
Sensitization to Ara h 7.0201 was most frequent (80%) and showed to be equally potent as Ara h 2.0201 and 6.01 in inducing basophil degranulation. Sensitization to Ara h 7.0201 together with Ara h 2.0201 and/or 6.01 was observed, indicating the presence of unique epitopes compared to the other 2 isoforms. Differences between the 3 Ara h 7 isoforms were observed in C-terminal cysteine residues, pepsin and trypsin cleavage sites and 3 single amino acid substitutions. CONCLUSION & CLINICAL RELEVANCE The majority of peanut-allergic patients are sensitized to isoform Ara h 7.0201, which is functionally as active as Ara h 2.0201 and 6.01. Unique epitopes are most likely located in the C-terminus or an allergenic loop region which is a known allergenic epitope region for Ara h 2.0201 and 6.01. Due to its unique epitopes and allergenicity, it is an interesting candidate to improve the diagnostic accuracy for peanut allergy.Palavras-chave
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Basófilos
/
Degranulação Celular
/
Hipersensibilidade a Amendoim
/
Antígenos de Plantas
/
Albuminas 2S de Plantas
/
Epitopos
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Limite:
Adult
/
Female
/
Humans
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Male
/
Middle aged
Idioma:
En
Revista:
Clin Exp Allergy
Assunto da revista:
ALERGIA E IMUNOLOGIA
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Holanda