Comparison of molecular Structure among allergens of helminthic parasites

为了研究蠕虫变应原的结构同源性，构建了旋毛虫、巴西日圆线虫和柯氏中圆线虫的cDNA文库。通过感染血清和抗IgG抗体的免疫筛选，从cDNA文库中获得了8个新的cDNA。氨基酸序列没有发现明显的同源性。本研究采用抗IgE单克隆抗体包被板、β-半乳糖苷酶融合重组抗原和抗β-半乳糖苷酶抗体建立了检测变应原特异性IgE的夹心ELISA系统。使用这种方法证明，尽管所有测试的抗原都被感染血清和抗IgG抗体检测到，但针对某些抗原产生IgE。这些结果表明，抗原分为两种类型：一种诱导产生抗原特异性IgE，另一种不诱导产生。本研究拟从免疫学角度阐明不同性质变应原诱导特异性IgE产生的机制。我们也在研究这些过敏原对辅助性T细胞产生Th 2细胞因子的作用。

In order to study the structural homology among allergens derived from helminths, cDNA libraries were made from Trichinella spiralis, Nippostrongylus brasiliensis and Mesocestoides corti. Eight novel cDNAs were obtained from cDNA libraries by immunoscreening using infection sera and anti-IgG antibody. No obvious homology in the amino acid sequence was found out among the cDNAs. This indicates that Th2 immune response is not induced by the common structure among the allergens.We next developed the sandwich ELISA system detecting allergen-specific IgE using anti-IgE monoclonal antibody-coated plate, recombinant antigen fused with β-galactosidase, and anti-β-galactosidase antibody. It was demonstrated using this method that IgE was produced against some of the antigens, although all the antigens tested were detected by infection sera and anti-IgG antibody. These results suggested that antigens were divided into two types: one induces production of antigen-specific IgE, and the other does not. We intend to clarify the mechanism of the different property of allergens inducing specific IgE production immunologically. We are also investigating the role of these allergens on the production of Th2 cytokines by helper T cells.