旋毛形线虫肌幼虫代谢分泌抗原的鉴定

Identification of serological antigens in excretory-secretory antigens of Trichinella spiralis muscle larvae

目的采用免疫共沉淀偶联质谱技术分离和鉴定旋毛形线虫肌幼虫代谢分泌抗原中的血清学抗原。方法收集感染旋毛形线虫的新西兰兔血清,硫酸铵沉淀法分离血清Ig G;从感染肌肉中分离纯化肌幼虫并培养收集代谢分泌抗原。免疫共沉淀和SDS-PAGE分离代谢分泌抗原,Western blot法分析血清学抗原,并予质谱鉴定。结果间接ELISA检测旋毛形线虫感染新西兰兔的血清抗体滴度达1∶6400以上;采用硫酸铵沉淀法获得血清Ig G。免疫共沉淀的旋毛形线虫肌幼虫代谢分泌抗原经电泳分离获得4条较清晰的蛋白质条带,Western blot法分析发现在相对分子质量(Mr)40 000、50 000、83 000处存在旋毛形线虫感染血清识别、而正常兔血清不识别的3条较强的蛋白质条带。切取Mr40 000、50 000、83 000处的蛋白质条带进行质谱鉴定,获得4种蛋白质分子,分别为丝氨酸蛋白酶、肌幼虫特异性丝氨酸蛋白酶、43 000分泌糖蛋白、53 000代谢分泌抗原。结论采用免疫共沉淀偶联质谱技术从旋毛形线虫肌幼虫代谢分泌抗原(ES)中获得4种血清学抗原,为旋毛形线虫病有效诊断和疫苗候选分子的获得提供了新的来源和视角。

Objective To isolate and identify serological antigens in the excretory-secretory antigens of Trichinella spiralis muscle larvae by the combination of co-immunoprecipitation and mass spectrometric technology. Methods The serum IgG of New Zealand rabbits infected with Trichinella spiralis was isolated by ammonium sulfate precipitation. Muscle larvaes were isolated from the infected muscle, and then purified and cultured to collect excretory-secretory antigens. Serological antigens in excretory-secretory antigens were isolated by co-immunoprecipitation and SDS-PAGE, and analyzed by Western blotting. Moreover, the protein bands in New Zealand rabbit sera infected with Trichinella spiralis were identified by mass spectrometric technology. Results Indirect ELISA showed that the titer of serum antibody of New Zealand rabbits infected with Trichinella spiralis was 1：6400. The rabbit serum IgG was effectively isolated by ammonium sulfate precipitation. A total of four clear protein bands of the excretory-secretory antigens of Trichinella spiralis were obtained by electrophoresis. Among them, three clear protein bands with relative molecular mass （Mr） being 40 kDa, 50 kDa and 83 kDa were recognized by the rabbit sera infected with Trichinella spiralis but not recognized by the normal rabbit sera. The obtained four protein molecules were confirmed as serine protease, specific serine protease of muscle larvae, 43 kDa secreted glycoprotein and 53 kDa excretory- secretory antigen. Conduslon Four proteins were obtained from the excretory-secretory antigens of Trichinella spiralis muscle larvae by combination of co-immunoprecipitation and mass spectrometric technique analysis, which provided new sources and insights for the diagnosis and vaccine candidates of Trichinellosis.