Institute for Immunological Research, University of Cartagena, Cartagena, Colombia.
Int Arch Allergy Immunol. 2011;154(3):195-206. doi: 10.1159/000321106. Epub 2010 Sep 21.
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.
cDNA was obtained by reverse transcription PCR, cloned into pQE30-UA and purified as a 6× 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.
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.
A. lumbricoides tropomyosin (Asc l 3) 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.
蛔虫在人体内诱导 Th2 反应和特异性 IgE 合成。这赋予了抗寄生虫免疫，但可能会改变热带地区过敏性疾病的自然病程，因此有必要研究其过敏原组成。我们分析了蛔虫肌球蛋白的过敏原特性以及暴露于寄生虫的受试者中致敏的频率。
通过反转录 PCR 获得 cDNA，克隆到 pQE30-UA 中，并作为 6×His 标记蛋白进行纯化。通过交叉抑制和液相色谱-串联质谱分析来分析其与天然蛋白的等效性。通过 ELISA 在 175 名哮喘患者和 170 名非哮喘患者中测量特异性 IgE，这些患者自然暴露于寄生虫并对蛔虫提取物敏感。
cDNA 编码 287 个残基，与其他无脊椎动物肌球蛋白具有高度序列同一性。40kDa 蛋白被人血清和亲和纯化的抗 rBlo t 10 IgE 识别。对肌球蛋白的特异性 IgE 可能代表提取物总 IgE 反应的约 50%。蛔虫肌球蛋白在皮肤点刺试验中引起风团和红晕，并从嗜碱性粒细胞中释放组胺。尽管哮喘患者中对蛔虫肌球蛋白的 IgE 患病率较高，但逻辑回归分析表明，这一结果受到对螨类过敏的影响。
A. lumbricoides tropomyosin（Asc l 3）是一种新的过敏原，可结合特异性 IgE，诱导效应细胞释放介质，并与螨类肌球蛋白发生交叉反应。对该过敏原的 IgE 反应在对蛔虫提取物敏感的哮喘和正常受试者中非常常见。蛔虫肌球蛋白在热带地区哮喘发病机制中的潜在作用应进一步研究。
