Wangorsch Andrea, Jamin Annette, Lidholm Jonas, Gräni Nora, Lang Claudia, Ballmer-Weber Barbara, Vieths Stefan, Scheurer Stephan
VPr1 Research Group Molecular Allergology, Paul-Ehrlich-Institut, Langen, Germany.
ThermoFisherScientific, Uppsala, Sweden.
Mol Nutr Food Res. 2017 Apr;61(4). doi: 10.1002/mnfr.201600902. Epub 2017 Feb 10.
English walnut (Juglans regia) belongs to the most important allergenic tree nuts. Co-sensitization with birch (Betula verrucosa) pollen has been reported. We aimed to identify a walnut allergen homologous to the major birch pollen allergen Bet v 1.
A cDNA encoding a Bet v 1-homologous allergen (Jug r 5) in walnut kernels was cloned by RT-PCR. Jug r 5 was expressed in Escherichia coli, purified by column chromatography and characterized by circular dichroism spectroscopy. Specific IgE levels to walnut, Bet v 1, and Jug r 5 in birch pollen allergics (n = 16) with concomitant walnut allergy were measured by ImmunoCAP: 44% of the patients were tested positive to walnut while 94% were reactive to Jug r 5, and 100% to Bet v 1. Jug r 5 and Bet v 1 allergens showed bidirectional IgE cross-reactivity by competitive ELISA and were capable of inducing histamine release from effector cells. Immunoblot competition experiments demonstrated the presence of IgE-reactive Jug r 5 in walnut extract, but at low levels.
A Bet v 1-like allergen was identified in walnut. Diagnostic use of Jug r 5 will compensate for the low sensitivity of walnut extract for patients with birch pollen associated walnut allergy.
英国胡桃（胡桃）属于最重要的致敏性坚果。已有报道其与桦树（疣枝桦）花粉存在共同致敏现象。我们旨在鉴定一种与主要桦树花粉过敏原Bet v 1同源的胡桃过敏原。
通过逆转录聚合酶链反应（RT-PCR）克隆了编码胡桃仁中Bet v 1同源过敏原（Jug r 5）的cDNA。Jug r 5在大肠杆菌中表达，经柱层析纯化，并通过圆二色光谱进行表征。采用免疫捕获法测定了16例伴有胡桃过敏的桦树花粉过敏患者对胡桃、Bet v 1和Jug r 5的特异性IgE水平：44%的患者对胡桃检测呈阳性，而94%对Jug r 5有反应，100%对Bet v 1有反应。通过竞争性酶联免疫吸附测定（ELISA），Jug r 5和Bet v 1过敏原显示出双向IgE交叉反应性，并且能够诱导效应细胞释放组胺。免疫印迹竞争实验证明胡桃提取物中存在IgE反应性Jug r 5，但水平较低。
在胡桃中鉴定出一种Bet v 1样过敏原。Jug r 5用于诊断将弥补胡桃提取物对伴有桦树花粉相关胡桃过敏患者的低敏感性。
