牛型分枝杆菌MPB70蛋白胶乳凝集方法的建立及应用

为了研究牛结核病新型诊断试剂，提高诊断的特异性和敏感性，我们用大肠杆菌工程菌表达了牛型分枝杆菌特异性抗原MPB70并提纯蛋白建立了牛结核病乳胶凝集试验（LAT）诊断方法。MPB70是一种牛型分枝杆菌特异性分泌而卡介苗BCG缺失的蛋白质，热稳定性好，用此蛋白建立的乳胶凝集方法具有良好的敏感性、特异性以及较长的保存期，检测70份临床奶牛血清，与皮内变态反应和间接血凝方法相比较分别具有71．4％和88．6％的符合率。该方法还可鉴别诊断自然感染和疫苗免疫接种。我们建立的牛型分枝杆菌MPB70蛋白乳胶凝集试验诊断方法将分子生物学手段和经典试验方法有机结合，为临床快速检测牛结核病血清特异性抗体水平提供了行之有效的方法。

Development and application of a latex agglutination test based on the MPB70 protein of Mycobacterium bovis

To improve bovine tuberculosis (bTB) diagnosis, a latex agglutination test (LAT) was developed for detecting antibodies against the specific antigen MPB70 of Mycobacterium bovis. The MPB70 antigen was specific to Mycobacterium bovis and was minimally expressed in BCG. Recombinant MPB70 protein was expressed by E.coli, purified to near homogeneity, and was used to sensitize latex beads. The protein has heat stability and the resulting LAT beads were stable for months and demonstrated reasonable sensitivity and high specificity when used to detect serum from 70 cows with different infections. The LAT was particularly simple to perform and could be used on farms. The results indicated that the MPB70-LAT is a candidate method for epidemiological surveys and diagnosis of bovine tuberculosis.