Kashiwazaki Y, Thammasart S
National Institute of Animal Health, Bangkok, Thailand.
Int J Parasitol. 1998 Sep;28(9):1353-60. doi: 10.1016/s0020-7519(98)00123-4.
The possibility of interference with the antigen-detection ELISA for trypanosomosis by anti-rodent IgG antibodies produced in cattle infected with Trypanosoma evansi was investigated. Two different ELISA for detection of trypanosome antigen and three different systems for anti-rodent IgG antibody detection were established. The former two were respectively polyclonal antibody-based and a combination of monoclonal and polyclonal antibody-based assays. The latter three were also adapted for detection of anti-mouse IgG, anti-rabbit IgG and anti-IgG antibodies cross-reactive with both rabbit and mouse IgGs. A total of 170 samples were collected from a dairy cattle farm where an outbreak of T. evansi infection was reported. One hundred and two cattle (59%) were found to be positive for trypanosome antigens by the polyclonal antibody-based assay and 86 (51%) were positive by the combination-based system. On the other hand, 51 (30%) and 10 (6%) of cattle had anti-rabbit and anti-mouse IgG antibodies respectively but none had antibodies cross-reactive with both IgGs. Of the 102 cattle positive for trypanosome antigens in the polyclonal antibody-based ELISA, 48 (47%) were also anti-rabbit IgG antibody positive. It is concluded that antigen detection ELISA based on a single-species immunoglobulin for capture and detection might misdiagnose T. evansi infection. Results indicate that this bias will be avoided if reagents for capture and detection are derived from different species.
对感染伊氏锥虫的牛所产生的抗啮齿动物IgG抗体干扰锥虫病抗原检测ELISA的可能性进行了研究。建立了两种不同的用于检测锥虫抗原的ELISA以及三种不同的抗啮齿动物IgG抗体检测系统。前两种分别是基于多克隆抗体的检测方法和基于单克隆抗体与多克隆抗体联合的检测方法。后三种检测系统还适用于检测抗小鼠IgG、抗兔IgG以及与兔和小鼠IgG均发生交叉反应的抗IgG抗体。从一个报道有伊氏锥虫感染暴发的奶牛场共采集了170份样本。基于多克隆抗体的检测方法发现102头牛（59%）锥虫抗原呈阳性，基于联合检测系统的方法发现86头牛（51%）呈阳性。另一方面，分别有51头（30%）和10头（6%）牛含有抗兔和抗小鼠IgG抗体，但没有牛含有与两种IgG均发生交叉反应的抗体。在基于多克隆抗体的ELISA中锥虫抗原呈阳性的102头牛中，有48头（47%）抗兔IgG抗体也呈阳性。得出结论，基于单一物种免疫球蛋白进行捕获和检测的抗原检测ELISA可能会误诊伊氏锥虫感染。结果表明，如果捕获和检测试剂来源于不同物种，这种偏差将得以避免。
