Structural analyses of IgE-binding proteins originated from plant foodstuffs

据了解，对植物性食物过敏的患者每年都在增加。我们用患者的血清对植物食品中的过敏蛋白进行了研究，发现患者的IgE在涂料王国中广泛分布的许多同源蛋白中存在交叉反应。一些来自不同食物的IgE结合蛋白是糖蛋白，并与抗辣根过氧化物酶(HRP)抗体反应。这种抗HRP已知识别过氧化物酶上的天冬酰胺偶联和高甘露糖型糖基。用抗HRP处理变应原蛋白后，患者的IgE与植物变应原的结合活性显著降低，提示这些变应原的抗原表位是同源的，是高甘露糖型糖基。如果这些糖部分是植物过敏原的共同表位，患者的IgE抗体可以与植物食品中具有相似糖部分的许多同源蛋白反应，患者对许多超出分类的植物，如物种、属和科，表现出过敏症状。我们研究了一种含有天冬酰胺偶联的高甘露糖型糖基的植物过敏原Gly m Bd 28K和马铃薯的过敏原Patatin。这两种过敏性蛋白都有一个共同的表位来对抗病人的IgE抗体。此外，我们还揭示了许多其他植物蛋白可能具有针对患者血清的共同表位。

Patients allergic to plant foodstuffs are known to increase yearly. We have investigated the allergenic proteins in plant foodstuffs using patient's sera and revealed that patient's IgE are cross-reactive among many homlogous proteins which are widely distributed in paint kingdom. Some of the IgE-binding proteins derived from different foodstuffs are glycoproteins and react with antibody raised against horse radish peroxidase (anti HRP). This antiHRP is known to recognize a asparagine-conjugated and high mannose type sugar moiety on peroxidase. The binding activity of patient's IgE against plant's allergens was reduced remarkedly by the pre-treatment of allergenic proteins with antiHRP, suggesting that the epitopes of these allergens are homologous and to be high mannose type sugar moieties. If these sugar moieties are common epitopes of plant allergens, patient's IgE antibodies could react with many homologous proteins which have similar sugar moiety in plant foodstuffs and patients present allergic symptons against many plants beyond there classification, such as species, genus, and families. We investigate one of the plant allergen which has asparagine-conjugated high mannose type sugar moiety, Gly m Bd 28K and potato's allergen, patatin. Both the allergenic proteins found to have a common epitope against patient's IgE antibodies. Furthermore, we revealed that many other plant proteins might share the common epitopes against patient's sera.