Allergenicity of Ascaris lumbricoides Tropomyosin and IgE Sensitization among Asthmatic Patients in a Tropical Environment
Allergenicity of Ascaris lumbricoides Tropomyosin and IgE Sensitization among Asthmatic Patients in a Tropical Environment
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DOI：
10.1159/000321106
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发表时间：
2011-01-01
影响因子：
2.8
通讯作者：
Caraballo, L.
中科院分区：
文献类型：
--
作者：
Acevedo, N.;Erler, A.;Caraballo, L.
背景：类蛔虫诱导Th2反应和特异性IgE合成。这赋予了抗寄生虫的免疫力，但可能改变热带地区过敏性疾病的自然史，证明了对其致敏成分的研究是正确的。我们分析了蛔虫原肌球蛋白的致敏特性和暴露于寄生虫的受试者的致敏频率。方法：通过反转录PCR获得cDNA，克隆到pQE30-UA中，纯化为6x his标记蛋白。通过交叉抑制和液相色谱-串联质谱分析了其与天然对应物的等效性。采用ELISA法测定175例哮喘患者和170例自然暴露于蛔虫并对蛔虫提取物致敏的非哮喘患者的特异性IgE水平。结果：该cDNA编码287个与其他无脊椎动物原肌球蛋白序列高度同源的残基。40kda蛋白被人血清和亲和纯化的抗rblo识别为10ige。原肌球蛋白的特异性IgE约占提取物总IgE反应的50%。蛔虫原肌球蛋白在皮肤点刺试验和嗜碱性粒细胞组胺释放中诱导的轮状和光斑。虽然哮喘患者对蛔虫原肌球蛋白的IgE患病率较高，但logistic回归分析表明，这一结果受到对螨虫的致敏性的影响。结论：a . lumbricoides原肌球蛋白（Asc l3）是一种结合特异性IgE、诱导效应细胞释放介质并与螨原肌球蛋白发生交叉反应的新型变应原。对蛔虫提取物敏感的哮喘和正常受试者对该过敏原的IgE反应非常频繁。蛔虫原肌球蛋白在热带地区哮喘发病中的潜在作用有待进一步研究。版权所有：S. Karger AG，巴塞尔
Background: Ascaris lumbricoides induces a Th2 response and specific IgE synthesis in humans. This confers antiparasite immunity but could modify the natural history of allergic diseases in the tropics, justifying the study of its allergenic composition. We analyzed the allergenic properties of Ascaris tropomyosin and the frequency of sensitization in subjects exposed to the parasite. Methods: cDNA was obtained by reverse transcription PCR, cloned into pQE30-UA and purified as a 6x His-tagged protein. Equivalence with its natural counterpart was analyzed by cross-inhibition and liquid chromatography-tandem mass spectrometry. Specific IgE was measured by ELISA in 175 asthmatics and 170 nonasthmatics naturally exposed to the parasite and sensitized to the Ascaris extract. Results: The cDNA encoded 287 residues with high sequence identity with other invertebrate tropomyosins. The 40-kDa protein was recognized by human serum and affinity-purified anti-rBlo t 10 IgE. Specific IgE to tropomyosin could represent approximately 50% of the total IgE response to the extract. Ascaris tropomyosin induced wheal and flare in skin prick tests and histamine release from basophils. Although the prevalence of IgE to Ascaris tropomyosin was higher in asthmatic patients, logistic regression analysis suggested that this result was biased by sensitization to mites. Conclusions: A. lumbricoides tropomyosin (Asc l3) is a new allergen that binds specific IgE, induces mediator release from effector cells and is cross-reactive to mite tropomyosins. IgE reactivity to this allergen is very frequent in both asthmatic and normal subjects sensitized to Ascaris extract. The potential role of Ascaris tropomyosin in asthma pathogenesis in tropical regions should be further investigated. Copyright (C) 2010 S. Karger AG, Basel