Structural analyses of IgE-binding proteins originated from plant foodstuffs

对植物性食物过敏的病人每年都在增加。我们利用患者血清对植物性食品中的致敏蛋白进行了研究，发现患者的IgE与广泛分布于油漆界的许多同源蛋白存在交叉反应。从不同食品中提取的一些ige结合蛋白是糖蛋白，可与抗马萝卜过氧化物酶（anti HRP）抗体发生反应。这种抗hrp已知能识别过氧化物酶上的天冬酰胺偶联和高甘露糖型糖段。用抗hrp预处理过敏原蛋白后，患者IgE对植物过敏原的结合活性明显降低，提示这些过敏原的表位是同源的，是高甘露糖型糖段。如果这些糖段是植物过敏原的共同表位，则患者的IgE抗体可与植物性食物中具有相似糖段的许多同源蛋白发生反应，患者对许多超出其分类（如种、属、科）的植物出现过敏症状。我们研究了一种具有天冬酰胺偶联高甘露糖型糖段的植物过敏原Gly m b28k和马铃薯过敏原patatin。这两种过敏原蛋白都有一个共同的抗原表位来对抗患者的IgE抗体。此外，我们还发现许多其他植物蛋白可能具有共同的抗患者血清表位。

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.