Vassilopoulou Emilia, Rigby Neil, Moreno F Javier, Zuidmeer Laurian, Akkerdaas Jaap, Tassios Ioannis, Papadopoulos Nikos G, Saxoni-Papageorgiou Photini, van Ree Ronald, Mills Clare
Allergy Research Laboratories, 2nd Paediatric Clinic, University of Athens Greece, 41 Fidippidou str., Athens 11527, Greece.
J Allergy Clin Immunol. 2006 Aug;118(2):473-80. doi: 10.1016/j.jaci.2006.04.057. Epub 2006 Jul 3.
Severe grape allergy has been linked to lipid transfer protein (LTP) sensitization. LTPs are known to be resistant to pepsin digestion, although the effect of gastroduodenal digestion on its allergenicity has not been reported.
We sought to investigate the effect of gastric and gastroduodenal digestion on the allergenic activity of grape LTP.
The proteolytic stability of grape LTP was investigated by using an in vitro model of gastrointestinal digestion. The allergenicity of LTP and its digesta was assessed in vitro by means of IgE immunoblotting, RASTs, and in vivo skin prick tests in the same patients with grape allergy.
Grape LTP was resistant to gastric digestion, and yielded a 6000-d relative molecular mass C-terminally trimmed fragment after duodenal digestion. This fragment retained the in vitro IgE reactivity of the intact protein. Inclusion of phosphatidylcholine during gastric digestion protected the LTP to a limited extent against digestion. Digestion did not affect the in vivo (skin prick test) biologic activity of LTP.
The allergenic activity of grape LTP was highly resistant to in vitro digestion. This property might facilitate sensitization through the gastrointestinal tract and might also potentiate the ability of LTPs to elicit severe allergic reactions in sensitized individuals.
Purified natural allergens will facilitate the development of component-resolved diagnostic approaches, including allergen chips. This study contributes to our understanding of the role digestion plays in symptom elicitation in true food allergy.
严重的葡萄过敏与脂质转移蛋白（LTP）致敏有关。已知LTP对胃蛋白酶消化具有抗性，尽管胃十二指肠消化对其致敏性的影响尚未见报道。
我们试图研究胃和胃十二指肠消化对葡萄LTP致敏活性的影响。
通过使用胃肠道消化的体外模型研究葡萄LTP的蛋白水解稳定性。通过IgE免疫印迹、放射性过敏原吸附试验（RAST）以及在患有葡萄过敏的同一患者中进行体内皮肤点刺试验，在体外评估LTP及其消化产物的致敏性。
葡萄LTP对胃消化具有抗性，十二指肠消化后产生一个相对分子质量为6000道尔顿的C末端截短片段。该片段保留了完整蛋白的体外IgE反应性。胃消化过程中加入磷脂酰胆碱在一定程度上保护LTP免受消化。消化不影响LTP的体内（皮肤点刺试验）生物活性。
葡萄LTP的致敏活性对体外消化具有高度抗性。这一特性可能有助于通过胃肠道致敏，也可能增强LTP在致敏个体中引发严重过敏反应的能力。
纯化的天然过敏原将有助于开发包括过敏原芯片在内的组分分辨诊断方法。本研究有助于我们理解消化在真正食物过敏症状引发中所起的作用。
