PDF(Pubmed)
Abstract：
Pollen from common ragweed is an important allergen source worldwide and especially in western and southern Romania. More than 100 million patients suffer from symptoms of respiratory allergy (e.g., rhinitis, asthma) to ragweed pollen. Among the eleven characterized allergens, Amb a 6 is a non-specific lipid transfer protein (nsLTP). nsLTPs are structurally stable proteins in pollen and food from different unrelated plants capable of inducing severe reactions. The goal of this study was to produce Amb a 6 as a recombinant and structurally folded protein (rAmb a 6) and to characterize its physicochemical and immunological features. rAmb a 6 was expressed in Spodoptera frugiperda Sf9 cells as a secreted protein and characterized by mass spectrometry and circular dichroism (CD) spectroscopy regarding molecular mass and fold, respectively. The IgE-binding frequency towards the purified protein was evaluated using sera from 150 clinically well-characterized ragweed-allergic patients. The allergenic activities of rAmb a 6 and the nsLTP from the weed Parietaria judaica (Par j 2) were evaluated in basophil activation assays. rAmb a 6-specific IgE reactivity was associated with clinical features. Pure rAmb a 6 was obtained by insect cell expression. Its deduced molecular weight corresponded to that determined by mass spectrometry (i.e., 10,963 Da). rAmb a 6 formed oligomers as determined by SDS-PAGE under non-reducing conditions. According to multiple sequence comparisons, Amb a 6 was a distinct nsLTP with less than 40% sequence identity to currently known plant nsLTP allergens, except for nsLTP from Helianthus (i.e., 52%). rAmb a 6 is an important ragweed allergen recognized by 30% of ragweed pollen allergic patients. For certain patients, rAmb a 6-specific IgE levels were higher than those specific for the major ragweed allergen Amb a 1 and analysis also showed a higher allergenic activity in the basophil activation test. rAmb a 6-positive patients suffered mainly from respiratory symptoms. The assumption that Amb a 6 is a source-specific ragweed allergen is supported by the finding that none of the patients showing rAmb a 6-induced basophil activation reacted with Par j 2 and only one rAmb a 6-sensitized patient had a history of plant food allergy. Immunization of rabbits with rAmb a 6 induced IgG antibodies which strongly inhibited IgE binding to rAmb a 6. Our results demonstrate that Amb a 6 is an important source-specific ragweed pollen allergen that should be considered for diagnosis and allergen-specific immunotherapy of ragweed pollen allergy.
摘要：
来自普通斑草的花粉是世界范围内的重要过敏原来源，尤其是在罗马尼亚西部和南部。超过1亿患者患有呼吸道过敏症状(例如，鼻炎,哮喘）到参草花粉。在11种特征过敏原中，Amb一6是一种非特异性脂质转移蛋白(nsLTP)。nsLTPs是花粉和来自不同无关植物的食物中的结构稳定的蛋白质，能够诱导严重的反应。这项研究的目的是生产Amba6作为重组和结构折叠的蛋白质（rAmba6），并表征其物理化学和免疫学特征。rAmba6以分泌蛋白的形式在节食夜蛾Sf9细胞中表达，并通过质谱和圆二色性（CD）光谱对分子质量和倍数进行表征，分别。使用来自150名临床上充分表征的参草过敏患者的血清评估了针对纯化蛋白的IgE结合频率。在嗜碱性粒细胞活化试验中评估了来自杂草Parietariajudaica（Parj2）的rAmba6和nsLTP的致敏活性。rAmb一6特异性IgE反应性与临床特征相关。通过昆虫细胞表达获得纯rAmb一6。其推导的分子量对应于通过质谱法确定的分子量(即，10,963Da）。rAmbα6在非还原条件下通过SDS-PAGE测定形成寡聚体。根据多个序列比较,Amba6是一种独特的nsLTP，与目前已知的植物nsLTP过敏原具有不到40％的序列同一性，除了来自Helianthus的nsLTP(即，52%)。rAmb一6是30％的斑驳花粉过敏患者公认的重要斑驳变应原。对某些病人来说,rAmba6特异性IgE水平高于对主要的话草变应原Amba1特异性的水平,并且分析还显示在嗜碱性粒细胞活化试验中具有较高的变应原活性。rAmb一6阳性患者主要患有呼吸道症状。发现Amba6是一种特定来源的g草过敏原的假设得到了以下发现的支持：没有显示rAmba6诱导的嗜碱性粒细胞活化的患者与Parj2反应，只有一名rAmb6致敏的患者有植物性食物过敏史。用rAmba6免疫兔诱导的IgG抗体强烈抑制IgE与rAmba6的结合。我们的结果表明，Amba6是一种重要的来源特异性斑纹花粉过敏原，应考虑用于诊断和对斑纹花粉过敏的过敏原特异性免疫治疗。
