Background

Prosopis juliflora is a clinically relevant allergic sensitizer worldwide and shares cross-reactivity with allergens from several tree pollen and food. The present study aims to purify and immunobiochemically characterize a major allergen from Prosopis pollen. The allergen was further investigated for its cross-reactivity with legume allergens.

Methods

Prosopis extract was fractionated by Q Sepharose and Superdex 75 gel filtration column to purify the allergen. Specific IgE against purified protein was estimated via ELISA and immunoblot. The protein was subjected to mass spectrometric analysis. Glycan characterization was performed by Schiff staining and lectin binding assay followed by deglycosylation studies. The functional activity of the purified protein was evaluated by the basophil activation test. Cross-reactivity was assessed by inhibition studies with legume extracts.

Results

A 35 kDa protein was purified and showed 75% IgE reactivity with the patients’ sera by ELISA and immunoblot. Glycan characterization of protein demonstrated the presence of terminal glucose and mannose residues. A reduction of 40% and 27% in IgE binding was observed upon chemical and enzymatic deglycosylation of the protein, respectively. The glycoprotein allergen upregulates the expression of CD203c on basophils which was significantly reduced upon deglycosylation, signifying its biological ability to activate the effector cells. The identified protein shared significant homology with Lup an 1 from the lupine bean. Immunoblot inhibition studies of the purified allergen with legume extracts underlined high cross-reactive potential. Complete inhibition was observed with peanut and common bean, while up to 70% inhibition was demonstrated with soy, black gram, chickpea, and lima bean.

Conclusion

A 35 kDa vicilin-like major allergen was isolated from P. juliflora. The protein possesses glycan moieties crucial for IgE binding and basophil activation. Furthermore, the purified protein shows homology with Lup an 1 and exhibits cross-reactivity with common edible legume proteins.

中文翻译：

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鉴定与豆科植物食物过敏原具有交叉反应性的大花胡蜂中的类vicilin 主要过敏原

背景

Prosopis juliflora是世界范围内临床相关的过敏性致敏物，与来自几种树木花粉和食物的过敏原具有交叉反应性。本研究旨在纯化和免疫生化表征来自Prosopis花粉的主要过敏原。进一步研究了过敏原与豆类过敏原的交叉反应性。

方法

通过 Q Sepharose 和 Superdex 75 凝胶过滤柱对 Prosopis 提取物进行分级以纯化过敏原。通过ELISA和免疫印迹估计针对纯化蛋白质的特异性IgE。对该蛋白质进行质谱分析。聚糖表征通过希夫染色和凝集素结合测定进行，然后进行去糖基化研究。通过嗜碱性粒细胞活化试验评价纯化蛋白的功能活性。通过对豆类提取物的抑制研究来评估交叉反应性。

结果

一种 35 kDa 的蛋白质被纯化，并通过 ELISA 和免疫印迹显示与患者血清的 75% IgE 反应性。蛋白质的聚糖表征证明存在末端葡萄糖和甘露糖残基。在蛋白质的化学和酶促去糖基化后，分别观察到 IgE 结合减少 40% 和 27%。糖蛋白过敏原上调嗜碱性粒细胞上 CD203c 的表达，在去糖基化时显着降低，表明其具有激活效应细胞的生物学能力。鉴定的蛋白质与来自羽扇豆的 Lup an 1 具有显着的同源性。用豆类提取物对纯化的过敏原进行免疫印迹抑制研究强调了高交叉反应潜力。花生和普通豆观察到完全抑制，而大豆则显示高达 70% 的抑制，

结论

从P. juliflora中分离出一种 35 kDa 的类豌豆球蛋白主要过敏原。该蛋白质具有对 IgE 结合和嗜碱性粒细胞活化至关重要的聚糖部分。此外，纯化的蛋白质显示出与 Lup an 1 的同源性，并显示出与常见的可食用豆类蛋白质的交叉反应性。