Scheurer Stephan, Lauer Iris, Foetisch Kay, San Miguel Moncin Mar, Retzek Mechthild, Hartz Christina, Enrique Ernesto, Lidholm Jonas, Cistero-Bahima Anna, Vieths Stefan
Department of Allergology, Paul-Ehrlich-Institut, Langen, Germany.
J Allergy Clin Immunol. 2004 Oct;114(4):900-7. doi: 10.1016/j.jaci.2004.06.017.
Nonspecific lipid transfer proteins (nsLTPs) have been identified as major fruit allergens in patients from the Mediterranean area. Sensitization to nsLTPs is accompanied by severe reactions, possibly because of specific biophysical and biochemical properties of this allergen family.
To assess the protein stability and allergenic potency of nsLTP from fruits in comparison with birch pollen-related allergens from the same allergenic source.
Stability of natural and recombinant cherry allergens Pru av 3 (nsLTP), Pru av 1 (Bet v 1 homologue), and Pru av 4 (profilin) to pepsin digestion and to thermal processing and stability of allergens in skin prick test reagents was investigated by immunoblotting and/or circular dichroism spectroscopy. Moreover, allergenicity of processed and fresh fruits in regard to Pru av 1 and Pru av 3 was analyzed by histamine release assays.
Lipid transfer proteins showed the highest resistance to digestion by pepsin (rPru av 3 > rPru av 1 > rPru av 4). Immunologically active Pru av 3 was detectable after 2 hours of digestion by pepsin, whereas IgE reactivity of Pru av 1 and Pru av 4 was abolished within less than 60 minutes. In contrast with Pru av 1, IgE reactivity to nsLTPs was not diminished in thermally processed fruits, and secondary structures of purified Pru av 3 were more resistant to heating. Moreover, nsLTPs were stable components in skin prick test reagents. Histamine release assays confirmed the strong allergenicity of nsLTPs, which was not affected by protease treatment or thermal processing of fruits.
In contrast with birch pollen-related allergens, nsLTPs are highly stable to pepsin treatment and thermal processing and show higher allergenic potency. Therefore, nsLTPs have the potential to act as true food allergens, probably eliciting severe systemic reactions by reaching the intestinal mucosa in an intact and fully active form.
非特异性脂质转移蛋白（nsLTPs）已被确定为地中海地区患者的主要水果过敏原。对nsLTPs的致敏伴随着严重反应，这可能是由于该过敏原家族特定的生物物理和生化特性。
与来自同一过敏原源的桦树花粉相关过敏原相比，评估水果中nsLTP的蛋白质稳定性和致敏效力。
通过免疫印迹和/或圆二色光谱研究天然和重组樱桃过敏原Pru av 3（nsLTP）、Pru av 1（Bet v 1同源物）和Pru av 4（肌动蛋白结合蛋白）对胃蛋白酶消化、热处理的稳定性以及皮肤点刺试验试剂中过敏原的稳定性。此外，通过组胺释放试验分析加工水果和新鲜水果对Pru av 1和Pru av 3的致敏性。
脂质转移蛋白对胃蛋白酶消化的抗性最高（重组Pru av 3＞重组Pru av 1＞重组Pru av 4）。胃蛋白酶消化2小时后仍可检测到具有免疫活性的Pru av 3，而Pru av 1和Pru av 4的IgE反应性在不到60分钟内就消失了。与Pru av 1不同，热处理水果中nsLTPs的IgE反应性并未降低，纯化的Pru av 3的二级结构对加热更具抗性。此外，nsLTPs是皮肤点刺试验试剂中的稳定成分。组胺释放试验证实了nsLTPs的强致敏性，其不受水果蛋白酶处理或热处理的影响。
与桦树花粉相关过敏原相比，nsLTPs对胃蛋白酶处理和热处理具有高度稳定性，并表现出更高的致敏效力。因此，nsLTPs有可能作为真正的食物过敏原，可能以完整且完全活性的形式到达肠黏膜，引发严重的全身反应。
