与其他 Ara h 7 同工型相比，2S 蛋白 Ara h 7.0201 具有独特的表位，且在脱颗粒能力方面与 2S 蛋白 Ara h 2 和 6 相当。
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.
机构信息
Department of Dermatology/Allergology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.
Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.
出版信息
Clin Exp Allergy. 2018 Jul;48(7):890-897. doi: 10.1111/cea.13134. Epub 2018 Apr 11.
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.
背景
针对 2S 白蛋白蛋白 Ara h 2 和 6 的特异性 IgE 筛查对诊断花生过敏具有良好的阳性预测值。从第三个 2S 成员 Ara h 7 中，已经鉴定出 3 种同工型。它们的致敏性尚未阐明。
目的
本研究比较了 Ara h 7 同工型与 Ara h 2 和 6 的致敏性。
方法
通过 IgE 免疫印迹条确定 15 例 DBPCFC 确诊的花生过敏患者对重组 Ara h 2.0201、Ara h 6.01 和重组 Ara h 7 同工型的致敏情况。对 9 例患者进行嗜碱性粒细胞活化试验 (BAT)，以确定过敏原的 IgE 交联能力。对至少对 1 种 Ara h 7 同工型过敏的 5 例患者进行 BAT 浓度范围测试，以测试对过敏原的敏感性。使用 3D 预测模型和序列比对来可视化同工型之间的差异，并预测过敏原表位区域。
结果
Ara h 7.0201 的致敏最常见（80%），并且在诱导嗜碱性粒细胞脱颗粒方面与 Ara h 2.0201 和 6.01 同样有效。观察到 Ara h 7.0201 与 Ara h 2.0201 和/或 6.01 一起致敏，表明与其他 2 种同工型相比存在独特的表位。在 3 种 Ara h 7 同工型之间观察到 C 末端半胱氨酸残基、胃蛋白酶和胰蛋白酶切割位点以及 3 个单个氨基酸取代的差异。
结论和临床相关性
大多数花生过敏患者对同工型 Ara h 7.0201 致敏，其功能与 Ara h 2.0201 和 6.01 一样活跃。独特的表位很可能位于 C 末端或过敏原环区域，这是 Ara h 2.0201 和 6.01 的已知过敏原表位区域。由于其独特的表位和致敏性，它是提高花生过敏诊断准确性的一个有趣候选物。
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