Hangzhou Zheda Dixun Biogenetic Engineering Co., Ltd.

Release date：2018-11-13

Clinical & Experimental Allergy

[IF:5.158]

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
DOI: 10.1111/cea.13134
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.
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.
Conclusions: 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.
First Author:
S. M. Hayen
Correspondence:
Simone Hayen, Department of Dermatology/Allergology, UMC Utrecht, Utrecht, The Netherlands
All Authors:
S. M. Hayen, A. M. Ehlers, C. F. den Hartog Jager, J. Garssen, E. F. Knol, A. C. Knulst, W. Suer, L. E. M. Willemsen, H. G. Otten

2018-10-25 Article

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Release date：2018-11-13