应用免疫-PCR检测弓形虫循环抗原的实验研究

目的　控索弓形虫感染早期诊断方法。方法　用链亲素将生物素化的二抗和生物素化的 DNA偶联起来 ,通过PCR扩增标记 DNA检测固定的抗原 ,建立了弓形虫循环抗原免疫— PCR检测技术 ,用该技术和 EL ISA法平行检测系列稀释的弓形虫的感染鼠阳性血清中的 CAg以及实验感染鼠血清中 CAg的动态变化 ,对比研究二者之间的敏感性。结果　免疫—PCR法检测弓形虫 CAg吴阳性的血清最高稀释度为 1∶ 10 0 0 ,EL ISA法检测弓形虫 CAg呈阳性的血清最高稀释度为 1∶ 5 ,免疫— PCR最早在鼠感染弓形虫后第 3天测到 CAg,EL ISA最早在鼠感染弓形虫后第 5天测到 CAg。结论　免疫— PCR是一种特异性强、敏感性高的弓形虫 CAg检测方法 ,敏感性较 EL ISA法提高了 2 0 0倍 ,免疫— PCR检出阳性结果时间早 ,为弓形虫病早期诊断提供了科学依据

STUDY ON THE DETECTION OF TOXOPLASMACIRCULATING ANTIGENS USING IMMUNO-PCR

Aim to explore an assay for the early diagnosis of Toxoplasma infection. Methods Free streptavidin was used to attach a biotinylated DNA to the biotinylated second antibody, through amplication of the DNA label, antigen which bound with antibodies was detected, thus Toxoplasma circulating antigens Immuno-PCR assay was estabished.detecting the CAg in serial dilutions of serum and the dynamic variation of serum CAg of Toxoplasma in experimental infected mice using Immuno-PCR and ELISA parallely to compare the sensitivity Result The detection limit of the immuno-PCR was at about 1/1000 dilution, it was at 1/5 dilution for ELISA. CAg of Toxoplasma could be detected as early as the third day after infection using Immuno - pcr, Wheareas the ELISA on the same samples, revealed no detectable CAg elevations until fifth day after infection. Conclusion In comparison with CAg detecting by ELISA parallelly performed, this method is more sensitive than ELISA, The detection limit of the immuno-PCR was an 200 fold improvement compared with a conventional ELISA. the positive result could be detected earlier than that of ELISA,It provide scientific basis for early diagnosis of Toxoplasmosis.