Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria.
Mass Spectrometry Laboratory, Molecular Systems Research Unit, University of Liège, Liège, Belgium.
Sci Rep. 2018 Jul 27;8(1):11366. doi: 10.1038/s41598-018-29656-4.
Walnuts are ranked high in the list of the culprit foods inducing severe allergic reactions. Jug r 2 has been identified as a major allergen in common walnut by cDNA cloning from a somatic cell line. So far, studies were performed on the allergenic activity of recombinant Jug r 2, yet there is still no evidence about the physicochemical characteristics of the natural allergen. Therefore, we aimed to purify and deeply characterize natural Jug r 2 and to assess IgE cross-reactivity among vicilins from different tree nuts. Extensive mass spectrometry analysis of the obtained purified vicilin allowed identification of the protein sequence that displayed only 44% identity to Jug r 2. The newly identified vicilin (Jug r 6) was recognized by IgE of 26% in walnut allergic patients' sera tested. In contrast to Jug r 2, Jug r 6 displayed a remarkable level of cross-reactivity when tested with homologues from hazelnut, sesame and pistachio. It is the first report showing the necessity of proteomic studies to improve allergy component resolved diagnosis.
核桃在引起严重过敏反应的罪魁祸首食物清单中排名很高。通过从体细胞系 cDNA 克隆，已鉴定 Jug r 2 为普通核桃的主要过敏原。到目前为止，已经对重组 Jug r 2 的变应原活性进行了研究，但仍没有关于天然变应原的物理化学特性的证据。因此，我们旨在纯化和深入表征天然 Jug r 2，并评估来自不同树坚果的 vicilins 之间的 IgE 交叉反应性。对获得的纯化 vicilin 进行广泛的质谱分析，允许鉴定出与 Jug r 2 仅显示 44%同一性的蛋白质序列。在测试的 26%核桃过敏患者的血清中，新鉴定的 vicilin（Jug r 6）被 IgE 识别。与 Jug r 2 相比，当用榛子、芝麻和开心果的同源物进行测试时，Jug r 6 显示出显著的交叉反应性。这是第一个表明需要进行蛋白质组学研究以改善过敏成分解析诊断的报告。
