花生基质对胃模拟消化物中过敏原稳定性的影响：2S 白蛋白是短消化抗性肽 IgE 反应性的主要贡献者。

Influence of peanut matrix on stability of allergens in gastric-simulated digesta: 2S albumins are main contributors to the IgE reactivity of short digestion-resistant peptides.

机构信息

Faculty of Chemistry, Innovation Centre Ltd., Belgrade, Serbia.

University of Belgrade - Faculty of Chemistry, Center of Excellence for Molecular Food Sciences, Belgrade, Serbia.

出版信息

Clin Exp Allergy. 2018 Jun;48(6):731-740. doi: 10.1111/cea.13113. Epub 2018 Mar 13.

DOI:10.1111/cea.13113

PMID:29412488

Abstract

BACKGROUND

Most food allergens sensitizing via the gastrointestinal tract are stable proteins that are resistant to pepsin digestion, in particular major peanut allergens, Ara h 2 and Ara h 6. Survival of their large fragments is essential for sensitizing capacity. However, the immunoreactive proteins/peptides to which the immune system of the gastrointestinal tract is exposed during digestion of peanut proteins are unknown. Particularly, the IgE reactivity of short digestion-resistant peptides (SDRPs; <10 kDa) released by gastric digestion under standardized and physiologically relevant in vitro conditions has not been investigated.

OBJECTIVE

The aim of this study was to investigate and identify digestion products of major peanut allergens and in particular to examine IgE reactivity of SDRPs released by pepsin digestion of whole peanut grains.

METHODS

Two-dimensional gel-based proteomics and shotgun peptidomics, immunoblotting with allergen-specific antibodies from peanut-sensitized patients, enzyme-linked immunosorbent inhibition assay and ImmunoCAP tests, including far ultraviolet-circular dichroism spectroscopy were used to identify and characterize peanut digesta.

RESULTS

Ara h 2 and Ara h 6 remained mostly intact, and SDRPs from Ara h 2 were more potent in inhibiting IgE binding than Ara h 1 and Ara 3. Ara h 1 and Ara h 3 exhibited sequential digestion into a series of digestion-resistant peptides with preserved allergenic capacity. A high number of identified SDRPs from Ara h 1, Ara h 2 and Ara h 3 were part of short continuous epitope sequences and possessed substantial allergenic potential.

CONCLUSION AND CLINICAL RELEVANCE

Peanut grain digestion by oral and gastric phase enzymes generates mixture of products, where the major peanut allergens remain intact and their digested peptides have preserved allergenic capacity highlighting their important roles in allergic reactions to peanut.

摘要

背景

大多数通过胃肠道致敏的食物过敏原是耐胃蛋白酶消化的稳定蛋白，尤其是主要的花生过敏原 Ara h 2 和 Ara h 6。其较大片段的存活对于致敏能力至关重要。然而，在消化花生蛋白期间，胃肠道的免疫系统暴露于哪些免疫原性蛋白/肽仍不清楚。特别是，在标准化和生理相关的体外条件下，胃消化释放的短消化抗性肽（SDRP；<10 kDa）的 IgE 反应性尚未得到研究。

目的

本研究旨在研究和鉴定主要花生过敏原的消化产物，特别是检查胃蛋白酶消化整个花生颗粒释放的 SDRP 的 IgE 反应性。

方法

使用二维凝胶基蛋白质组学和鸟枪法肽组学、花生致敏患者的过敏原特异性抗体的免疫印迹、酶联免疫吸附抑制测定和 ImmunoCAP 测试（包括远紫外圆二色光谱）来鉴定和表征花生消化物。

结果

Ara h 2 和 Ara h 6 大部分保持完整，并且来自 Ara h 2 的 SDRP 比 Ara h 1 和 Ara 3 更能抑制 IgE 结合。Ara h 1 和 Ara h 3 表现出连续消化成一系列具有保留致敏能力的消化抗性肽。从 Ara h 1、Ara h 2 和 Ara h 3 中鉴定出的大量 SDRP 是短连续表位序列的一部分，具有很大的致敏潜力。