Dumètre Aurélien, Dardé Marie-Laure
UPRES EA3174, Neuroparasitologie et Neuroépidémiologie Tropicale, Faculté de Médecine, 2 Rue du Dr Marcland, F-87025 Limoges, France.
J Microbiol Methods. 2005 May;61(2):209-17. doi: 10.1016/j.mimet.2004.11.024. Epub 2005 Jan 6.
Recent outbreaks of waterborne toxoplasmosis have stimulated the development of sensitive methods to detect Toxoplasma gondii oocysts in samples suspected to be contaminated. The immunomagnetic separation (IMS) have been standardised to detect waterborne protozoa, but it did not exist for Toxoplasma oocysts. In this study, we describe two monoclonal antibodies (mAbs 3G4 and 4B6) produced against the oocyst wall, and the incorporation of mAb 3G4 in an IMS procedure. We found that an indirect IMS method gave better mean recoveries than a direct one (69.4% and 25.2%, respectively). Dissociation of oocyst_magnetic bead complexes was greatly improved by using a 2% aqueous H2SO4 solution instead of a 0.1 N HCl solution (82.8% and 17.4%, respectively). With these parameters, mean recoveries of less than 1000 oocysts ranged from 44.6% to 82.9%, depending on incubating temperature and buffer. Age of oocysts (1 or 12 months old) does not influence IMS performances. Results of this study indicate that the described IMS is an efficient technique to recover Toxoplasma oocysts.
近期水源性弓形虫病的爆发促使人们开发出灵敏的方法，以检测疑似受污染样本中的刚地弓形虫卵囊。免疫磁珠分离法（IMS）已被标准化用于检测水源性原生动物，但针对弓形虫卵囊的该方法并不存在。在本研究中，我们描述了两种针对卵囊壁产生的单克隆抗体（单克隆抗体3G4和4B6），以及将单克隆抗体3G4纳入免疫磁珠分离程序的情况。我们发现间接免疫磁珠分离法的平均回收率比直接法更高（分别为69.4%和25.2%）。使用2%的硫酸水溶液而非0.1 N盐酸溶液可大大提高卵囊 - 磁珠复合物的解离率（分别为82.8%和17.4%）。基于这些参数，根据孵育温度和缓冲液的不同，少于1000个卵囊的平均回收率在44.6%至82.9%之间。卵囊的保存时间（1个月或12个月）不影响免疫磁珠分离法的性能。本研究结果表明，所描述的免疫磁珠分离法是一种回收弓形虫卵囊的有效技术。
