Molecular cloning and epitope analysis of the peanut allergen Ara h 3
Molecular cloning and epitope analysis of the peanut allergen Ara h 3
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DOI：
10.1172/jci5349
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发表时间：
1999-02-01
影响因子：
15.9
通讯作者：
Bannon, GA
中科院分区：
文献类型：
--
作者：
Rabjohn, P;Helm, EM;Bannon, GA
花生过敏是一个重要的IgE介导的健康问题，因为增加的患病率，潜在的严重性和慢性反应。在我们的两个花生过敏原阿糖胞苷h 1和Am h 2的表征，我们已经分离出编码第三花生过敏原，阿糖胞苷h 3的cDNA克隆。推导的氨基酸序列与11S种子贮藏蛋白同源。该蛋白的重组形式在细菌系统中表达，并被来自我们的花生过敏患者人群的45%的血清IgE识别。来自这些患者的血清IgE和重叠的合成肽用于绘制Ara h 3的线性IgE结合表位。在一级序列中发现了长度在10至15个氨基酸之间的四个表位，这些肽没有明显的序列基序。一个表位被所有Ara h 3过敏患者识别。表位的突变分析显示，这些肽内的单个氨基酸变化可能导致IgE结合的减少或丧失。通过确定哪些氨基酸对IgE结合是关键的，有可能改变Ara h 3 cDNA以编码具有降低的IgE结合能力的蛋白质。这些结果将使设计改进的诊断和治疗方法的食物过敏反应。
Peanut allergy is a significant IgE-mediated health problem because of the increased prevalence, potential severity, and chronicity of the reaction. Following our characterization of the two peanut allergens Ara h 1 and Am h 2, we have isolated a cDNA clone encoding a third peanut allergen, Ara h 3. The deduced amino acid sequence of Ara h 3 shows homology to 11S seed-storage proteins. The recombinant form of this protein was expressed in a bacterial system and was recognized by serum IgE from similar to 45% of our peanut-allergic patient population. Serum IgE from these patients and overlapping, synthetic peptides were used to map the linear, IgE-binding epitopes of Ara h 3. Four epitopes, between 10 and 15 amino acids in length, were found within the primary sequence, with no obvious sequence motif shared by the peptides. One epitope is recognized by all Ara h 3-allergic patients. Mutational analysis of the epitopes revealed that single amino acid changes within these peptides could lead to a reduction or loss of IgE binding. By determining which amino acids are critical for IgE binding, it might be possible to alter the Ara h 3 cDNA to encode a protein with a reduced IgE-binding capacity. These results will enable the design of improved diagnostic and therapeutic approaches for food-hypersensitivity reactions.