Unidad de Bioquímica, Departamento de Biotecnología, ETS Ingenieros Agrónomos, Universidad Politécnica, Madrid, Spain.
Pediatr Allergy Immunol. 2011 Mar;22(2):186-95. doi: 10.1111/j.1399-3038.2010.01125.x. Epub 2011 Feb 1.
Banana fruit allergy is well known, but neither immunoglobulin E recognition patterns to purified plant food allergens nor true prevalences of putative banana allergens have been established. This study aimed to characterize β-1,3-glucanase and thaumatin-like protein (TLP) as banana allergens, testing them, together with other plant food allergens, in 51 children with allergic reactions after banana ingestion and both positive specific IgE and skin prick test (SPT) to banana. Banana β-1,3-glucanase and TLP were isolated and characterized. Both banana allergens, together with kiwifruit TLP Act d 2, avocado class I chitinase Pers a 1, palm pollen profilin Pho d 2 and peach fruit lipid transfer protein (LTP) Pru p 3, were tested by in vitro and in vivo assays. Banana β-1,3-glucanase (Mus a 5) was glycosylated, whereas banana TLP (Mus a 4) was not, in contrast with its homologous kiwi allergen Act d 2. Specific IgE to both banana allergens, as well as to peach Pru p 3, was found in over 70% of sera from banana-allergic children, and Mus a 4 and Pru p 3 provoked positive SPT responses in 6 of the 12 tested patients, whereas Mus a 5 in only one of them. Both peptidic epitopes and cross-reactive carbohydrate determinants were involved in the IgE-binding to Mus a 5, whereas cross-reactivity between Mus a 4 and Act d 2 was only based on common IgE protein epitopes. Profilin Pho d 2 elicited a relevant proportion of positive responses on in vitro (41%) and in vivo (58%) tests. Therefore, Mus a 4 and LTP behave as major banana allergens in the study population, and profilin seems to be also a relevant allergen. Mus a 5 is an equivocal allergenic protein, showing high IgE-binding to its attached complex glycan, and low in vivo potency.
香蕉过敏众所周知,但尚未明确鉴定纯化植物食物过敏原的免疫球蛋白 E 识别模式和真正的潜在香蕉过敏原的流行率。本研究旨在鉴定β-1,3-葡聚糖酶和硫胺素类似蛋白(TLP)为香蕉过敏原,并用其与其他植物食物过敏原共同检测 51 例因摄入香蕉而发生过敏反应、对香蕉具有特异性 IgE 和皮肤点刺试验(SPT)阳性的患儿。分离和鉴定了香蕉β-1,3-葡聚糖酶和 TLP。体外和体内试验检测了这两种香蕉过敏原,以及猕猴桃 TLP Act d 2、鳄梨类几丁质酶 Pers a 1、手掌花粉丝氨酸蛋白酶 Pho d 2 和桃果实脂质转移蛋白(LTP)Pru p 3。与同源猕猴桃过敏原 Act d 2 相反,香蕉 TLP(Mus a 4)无糖基化,但香蕉β-1,3-葡聚糖酶(Mus a 5)有糖基化。在 51 例香蕉过敏患儿的血清中,超过 70%的血清检测到对这两种香蕉过敏原以及桃 Pru p 3 的特异性 IgE,Mus a 4 和 Pru p 3 在 12 例测试患者中的 6 例中引发了阳性 SPT 反应,而 Mus a 5 仅在 1 例中引发阳性 SPT 反应。Mus a 5 的 IgE 结合涉及肽表位和交叉反应性碳水化合物决定簇,而 Mus a 4 和 Act d 2 之间的交叉反应仅基于共同的 IgE 蛋白表位。丝氨酸蛋白酶 Pho d 2 在体外(41%)和体内(58%)试验中引起了相当比例的阳性反应。因此,在研究人群中,Mus a 4 和 LTP 是主要的香蕉过敏原,而丝氨酸蛋白酶似乎也是一种相关过敏原。Mus a 5 是一种可疑的过敏原蛋白,其与附着的复杂糖结合具有高 IgE 结合活性,而体内效力较低。