Specific IgE to peanut 2S albumin Ara h 7 has a discriminative ability comparable to Ara h 2 and 6

Blankestijn, Mark A.; Otten, Henny G.; Suer, Waltraud; Weimann, Alf; Knol, Edward F.; Knulst, André C.

doi:10.1111/cea.13030

Cited by 22 publications

(52 citation statements)

References 20 publications

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“…Taking together previous data and the data presented in this study, we hypothesize that determining specific IgE for Ara h 7.0201 can be of additional value in peanut allergy diagnosis. Ara h 7.0201 contains unique epitopes and is functionally as active as Ara h 2.0201 and Ara h 6.01 in inducing basophil degranulation.…”

Section: Discussionsupporting

confidence: 69%

“…Although Ara h 7.0201 contains cross‐reactive epitopes with Ara h 2.0201 and 6.01, a previous study indicated that monosensitization against Ara h 7.0201 was observed in 2 of 15 patients . This suggests that Ara h 7.0201 indeed contains 1 or more epitopes not present on the other Ara h 7 isoforms or Ara h 2.0201 and 6.01.…”

Section: Discussionmentioning

confidence: 97%

“…Next to these 2 isoforms of Ara h 7, a third isoform labelled Ara h 7.0301 shares 70% sequence identity with Ara h 7, and was also identified in peanut extract . Previous research indicated the presence of unique epitopes in these Ara h 7 isoforms, and therefore, they may be relevant in peanut allergy diagnosis …”

Section: Introductionmentioning

confidence: 98%

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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

Hayen

Ehlers

Jäger

et al. 2018

Clin Experimental Allergy

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Summary 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.

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Section: Discussionsupporting

confidence: 69%

Section: Discussionmentioning

confidence: 97%

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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

Hayen

Ehlers

Jäger

et al. 2018

Clin Experimental Allergy

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“…IgE‐binding to this allergen cannot be fully inhibited by Ara h 7.0101, although IgE‐binding to Ara h 7.0101 was completely inhibited by Ara h 7.0201. This data suggest the presence of unique epitopes on Ara h 7.0201 . By amino acid sequence comparisons, these unique epitopes might be located on the distinctive C‐terminus or created by amino acid substitutions within the flexible loops that are sensitive to pepsin or trypsin .…”

Section: Introductionmentioning

confidence: 86%

“…The cut‐off level was chosen to guarantee the detection of a broad epitope spectrum. In the next phase, the identified epitopes were validated by 25 DBPCFC‐confirmed peanut allergic (n = 22) or tolerant (n = 3) patients with sIgE levels ≥3 intensity units for Ara h 7.0201 (validation cohort) . As control, 10 sera without sIgE to Ara h 7.0201 were used.…”

Section: Methodsmentioning

confidence: 99%

Ara h 7 isoforms share many linear epitopes: Are 3D epitopes crucial to elucidate divergent abilities?

Ehlers

Klinge

Suer

et al. 2019

Clin Experimental Allergy

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Background The peanut allergens Ara h 2, h 6, and h 7 are potent allergens and can trigger severe reactions. Ara h 7 consists of three isoforms differing in their ability to induce basophil degranulation, whereas the ability of Ara h 7.0201 is comparable to Ara h 2 and 6 as shown in previous literature. Objective To identify linear epitopes of Ara h 7.0101, Ara h 7.0201 and Ara h 7.0301 recognized by IgE and IgG4 from patients sensitized to Ara h 7 and to investigate their potential to elucidate divergent abilities of the Ara h 7 isoforms in inducing basophil activation. Methods Linear epitopes recognized by IgE and IgG4 were mapped by peptide microarray analysis containing 15‐mer peptides of Ara h 2.0201, 6, 7.0101, 7.0201 and 7.0301 and 39 peanut allergic patients sensitized to Ara h 7 (discovery). For validation, 20‐mer peptides containing the minimal epitope and surrounding amino acids were incubated with 25 sensitized patients and 10 controls (validation). Results Three out of 14 linear epitopes were unique for each isoform (Ara h 7.0101: aa 97‐109; Ara h 7.0201: aa 122‐133; Ara h 7.0301: aa 65‐74) but scarcely recognized by IgE. The main linear IgE epitope (aa 51‐57) located in the long flexible loop of all Ara h 7 isoforms was bound by antibodies from 31% of the patients (discovery and validation cohort). Regarding IgG4, 55% of the patients recognized an epitope present on all isoforms (aa 55‐65), whereas epitope aa 129‐137, only present on Ara h 7.0101/0.0301, was recognized by 38% of the patients. Recognition was highly individual, although 20% of the patients recognized any linear epitope neither by IgE nor by IgG4 despite a low mean z‐score of ≥ 1.7. Remarkably, only 50% of the patients recognized one or more epitopes by IgE. Conclusion & Clinical Relevance Ara h 7 isoforms share many linear epitopes being easily accessible for antibody binding. Unique epitopes, essential to elucidate divergent potencies, were scarcely recognized, suggesting a crucial involvement of conformational epitopes.

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Specific IgE to individual allergen components: Peanut

Ehlers,

Knol,

Koppelman

2024

Encyclopedia of Food Allergy

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Specific IgE to peanut 2S albumin Ara h 7 has a discriminative ability comparable to Ara h 2 and 6

Abstract: SummaryBackground: Little is known on the clinical relevance of peanut 2S albumin Ara h 7.

Cited by 22 publications

References 20 publications

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

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

Ara h 7 isoforms share many linear epitopes: Are 3D epitopes crucial to elucidate divergent abilities?

Specific IgE to individual allergen components: Peanut

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