Development of diagnostic system for summer-type hypersensitivity pneumonitis

夏季过敏性肺炎是一种独特的过敏性肺炎类型，在日本最为流行。我们先前的研究表明，该病的病原体是皮肤毛孢子虫。在这项研究中，我们构建了一种诊断夏季过敏性肺炎的夹心酶联免疫吸附试验系统，其中针对II型T.cutaneum的单抗D-8被用来将与血清型相关的多糖结合到塑料平板上，该系统被证明具有足够的敏感性和特异性。亲和纯化的抗原主要是酸性多糖，包括甘露糖、木糖和葡萄糖醛酸。化学分析表明，该多糖抗原含有一个(1-3)连接的甘露聚糖主链和一小部分(1-2)连接的木糖残基，取代主链上(1-3)连接的甘露糖残基的2-或4位。用抗D-8单抗进行免疫扩散试验和夹心酶联免疫吸附试验表明，该抗原表位含有葡萄糖醛酸端残基。

Summer-type hypersensitivity pneumonitis is a unique type of hypersensitivity pneumonitis and the most prevalent in Japan. Our previous study clarified that the causative agent of the disease is Trichosporon cutaneum. In this study, we constructed a sandwich enzyme-linked immunosorbent assay system for diagnosis of summer-type hypersensitivity pneumonitis in which monoclonal antibody, D-8, specific for serotype II T.cutaneum was used to bind serotype-related polysaccharides to plastic plates, and this system was proven to have sufficient sensitivity and specificity.The affinity-purified antigen was shown to be essentially acidic polysaccharide comprising mannose, xylose, and glucuronic acid. Chemical analysis showed that this polysaccharide antigen contains a (1-3)-linked mannan backbone attached with short chains of (1-4)-linked mannose and a small portion of (1-2) linked xylose residues by substituting the 2- or 4- positions of the (1-3)-linked mannose residues of the main chain. The antigenic epitope was shown to involve the terminal glucuronic acid residues as revealed by immunodiffusion test and sandwich enzyme-linked immunosorbent assay using monoclonal antibody D-8.