一种 unfolded 变异的主要花生过敏原 Ara h 2，其过敏潜力降低。
An unfolded variant of the major peanut allergen Ara h 2 with decreased anaphylactic potential.
机构信息
Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria.
出版信息
Clin Exp Allergy. 2012 Dec;42(12):1801-12. doi: 10.1111/cea.12031.
BACKGROUND
Peanut allergy causes severe type 1 hypersensitivity reactions and conventional immunotherapy against peanut allergy is associated with a high risk of anaphylaxis.
OBJECTIVE
Our current study reports proof of concept experiments on the safety of a stably denatured variant of the major peanut allergen Ara h 2 for immunotherapy. We determined the impact of structure loss of Ara h 2 on its IgE binding and basophil degranulation capacity, T cell reactivity as well as anaphylactic potential.
METHODS
The secondary structure of untreated and reduced/alkylated Ara h 2 variants was determined by circular dichroism spectroscopy. We addressed human patient IgE binding to Ara h 2 by ELISA and Western blot experiments. RBL-SX38 cells were used to test the degranulation induced by untreated and reduced/alkylated Ara h 2. We assessed the anaphylactic potential of Ara h 2 variants by challenge of sensitized BALB/c mice. T cell reactivity was investigated using human Ara h 2-specific T cell lines and splenocytes isolated from sensitized mice.
RESULTS
Reduction/alkylation of Ara h 2 caused a decrease in IgE binding capacity, basophil degranulation and anaphylactic potential in vivo. However, the human T cell response to reduced/alkylated and untreated Ara h 2 was comparable. Mouse splenocytes showed higher metabolic activity upon stimulation with reduced/alkylated Ara h 2 and released similar IL-4, IL-13 and IFNγ levels upon treatment with either Ara h 2 variant.
CONCLUSIONS AND CLINICAL RELEVANCE
Reduced/alkylated Ara h 2 might be a safer alternative than native Ara h 2 for immunotherapeutic treatment of peanut allergic patients.
背景
花生过敏会导致严重的 1 型超敏反应，而针对花生过敏的常规免疫疗法与过敏反应的高风险相关。
目的
我们目前的研究报告了一种主要花生过敏原 Ara h 2 的稳定变性变体用于免疫治疗的安全性概念验证实验。我们确定了 Ara h 2 结构丢失对其 IgE 结合和嗜碱性粒细胞脱颗粒能力、T 细胞反应性以及过敏潜力的影响。
方法
未经处理和还原/烷基化 Ara h 2 变体的二级结构通过圆二色光谱法确定。我们通过 ELISA 和 Western blot 实验研究了人类患者 IgE 与 Ara h 2 的结合。使用 RBL-SX38 细胞测试未经处理和还原/烷基化 Ara h 2 诱导的脱颗粒。我们通过致敏 BALB/c 小鼠的挑战来评估 Ara h 2 变体的过敏潜力。使用人类 Ara h 2 特异性 T 细胞系和从致敏小鼠中分离的脾细胞研究了 T 细胞反应性。
结果
Ara h 2 的还原/烷基化导致 IgE 结合能力、嗜碱性粒细胞脱颗粒和体内过敏潜力降低。然而，人类 T 细胞对还原/烷基化和未经处理的 Ara h 2 的反应是可比的。用还原/烷基化的 Ara h 2 刺激后，小鼠脾细胞显示出更高的代谢活性，并且在用两种 Ara h 2 变体处理时释放出相似水平的 IL-4、IL-13 和 IFNγ。
结论和临床相关性
与天然 Ara h 2 相比，还原/烷基化的 Ara h 2 可能是治疗花生过敏患者免疫治疗的更安全选择。
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