Ikeda J S, BonDurant R H, Corbeil L B
Department of Pathology, University of California San Diego Medical Center 92103-8416, USA.
J Clin Microbiol. 1995 May;33(5):1158-63. doi: 10.1128/jcm.33.5.1158-1163.1995.
Bovine trichomoniasis is a prevalent sexually transmitted disease of cattle caused by the protozoan Tritrichomonas foetus. Currently, diagnosis is most often made by culture. In order to provide a faster immunodiagnostic approach, a specific enzyme-linked immunosorbent assay (ELISA) was investigated. A protective surface antigen (TF1.17 antigen) of T. foetus was immunoaffinity purified and used in an ELISA to detect antibodies in vaginal mucus from heifers inoculated with T. foetus. In preliminary studies, antibodies of the immunoglobulin A (IgA) isotype were detected in mucus from all experimentally infected heifers which were tested at 6 weeks postinoculation, whereas IgG1 and IgG2 were not. In addition, IgA responses detected in postinoculation samples were all greater than those detected in preinoculation samples, unlike those detected by a whole-cell antigen ELISA. For these two reasons, IgA antibodies appeared to be useful diagnostically. Further investigation of IgA antibodies used vaginal mucus collected weekly from heifers inoculated intravaginally with 10(2), 10(4), or 10(6) T. foetus organisms. Heifers with positive cultures for T. foetus had similar IgA responses to TF1.17 antigen over the 10 weeks of infection regardless of the initial inoculum dose. This indicates that if the dose is sufficient to establish infection, the magnitude and duration of the immune response are no longer dependent on dose. All of the infected animals receiving all dosages responded with high absorbance values in the IgA anti-TF1.17 antigen ELISA by 6 weeks postinoculation, and all absorbance values remained high at 10 weeks. To determine the duration of the IgA response, four other heifers inoculated with 7 x 10(6) T. foetus organisms were studied through 24 weeks postinoculation. IgA antibody responses to TF1.17 antigen were still high at 24 weeks, even though some heifers cleared the infection several weeks earlier. These results indicate that experimentally infected heifers produced detectable long-lasting IgA responses to TF1.17 antigen in vaginal mucus, which may be useful in a herd test for the diagnosis of bovine trichomoniasis.
牛毛滴虫病是由原生动物胎儿三毛滴虫引起的一种牛的常见性传播疾病。目前，诊断大多通过培养进行。为了提供一种更快的免疫诊断方法，对一种特异性酶联免疫吸附测定（ELISA）进行了研究。胎儿三毛滴虫的一种保护性表面抗原（TF1.17抗原）通过免疫亲和法纯化，并用于ELISA中，以检测接种胎儿三毛滴虫的小母牛阴道黏液中的抗体。在初步研究中，在接种后6周进行检测的所有经实验感染的小母牛的黏液中均检测到免疫球蛋白A（IgA）同种型抗体，而未检测到IgG1和IgG2。此外，接种后样本中检测到的IgA反应均大于接种前样本中检测到的反应，这与全细胞抗原ELISA检测到的情况不同。基于这两个原因，IgA抗体在诊断上似乎很有用。对IgA抗体的进一步研究使用了每周从经阴道接种10²、10⁴或10⁶个胎儿三毛滴虫生物体的小母牛收集的阴道黏液。胎儿三毛滴虫培养呈阳性的小母牛在感染的10周内对TF1.17抗原具有相似的IgA反应，无论初始接种剂量如何。这表明如果剂量足以引发感染，免疫反应的强度和持续时间就不再依赖于剂量。所有接受所有剂量接种的感染动物在接种后6周时，其IgA抗TF1.17抗原ELISA中的吸光度值都很高，并且在10周时所有吸光度值仍保持较高水平。为了确定IgA反应的持续时间，对接种7×10⁶个胎儿三毛滴虫生物体且在接种后24周内进行研究的另外4头小母牛进行了研究。即使一些小母牛在几周前就清除了感染，但在24周时对TF1.17抗原的IgA抗体反应仍然很高。这些结果表明，经实验感染的小母牛在阴道黏液中对TF1.17抗原产生了可检测到的持久IgA反应，这可能在牛群牛毛滴虫病诊断检测中有用。
