Neosporosis and toxoplasmosis are major causes of abortion in livestock worldwide, leading to substantial economic losses. Detection tools are fundamental to the diagnosis and management of those diseases. Current immunohistochemistry (IHC) tests, using sera raised against whole parasite lysates, have not been able to distinguish between Toxoplasma gondii and Neospora caninum. We used T. gondii and N. caninum recombinant proteins, expressed in Escherichia coli and purified using insoluble conditions, to produce specific polyclonal rabbit antisera. We aimed to develop species-specific sera that could be used in IHC on formalin-fixed, paraffin-embedded (FFPE) tissue sections to improve the diagnosis of ruminant abortions caused by protozoa. Two polyclonal rabbit sera, raised against recombinant proteins, anti– Neospora-rNcSRS2 and anti– Toxoplasma-rTgSRS2, had specificity for the parasite they were raised against. We tested the specificity for each polyclonal serum using FFPE tissue sections known to be infected with T. gondii and N. caninum. The anti– Neospora-rNcSRS2 serum labeled specifically only N. caninum–infected tissue blocks, and the anti– Toxoplasma-rTgSRS2 serum was specific to only T. gondii–infected tissues. Moreover, tissues from 52 cattle and 19 sheep previously diagnosed by lesion profiles were tested using IHC with our polyclonal sera and PCR. The overall agreement between IHC and PCR was 90.1% for both polyclonal anti-rNcSRS2 and anti-rTgSRS2 sera. The polyclonal antisera were specific and allowed visual confirmation of protozoan parasites by IHC, but they were not as sensitive as PCR testing.

中文翻译：

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评估用于检测和区分犬新孢子虫和弓形虫的物种特异性多克隆抗体

新孢子虫病和弓形体病是全世界牲畜流产的主要原因，造成巨大的经济损失。检测工具对于这些疾病的诊断和管理至关重要。目前的免疫组织化学 (IHC) 测试使用针对整个寄生虫裂解物的血清，无法区分弓形虫和犬新孢子虫。我们使用弓形虫和犬新孢子虫重组蛋白，在大肠杆菌中表达并使用不溶性条件纯化，以产生特异性多克隆兔抗血清。我们的目标是开发可用于福尔马林固定石蜡包埋 (FFPE) 组织切片 IHC 的物种特异性血清，以改善对原虫引起的反刍动物流产的诊断。两种针对重组蛋白（抗新孢子虫-rNcSRS2 和抗弓形虫-rTgSRS2）的多克隆兔血清，对它们所针对的寄生虫具有特异性。我们使用已知感染弓形虫和犬新孢子虫的 FFPE 组织切片测试了每种多克隆血清的特异性。抗新孢子虫-rNcSRS2血清仅特异性标记犬新孢子虫感染的组织块，抗弓形虫-rTgSRS2血清仅特异性标记刚地弓形虫感染的组织。此外，使用 IHC 以及我们的多克隆血清和 PCR 对先前通过病变特征诊断的 52 头牛和 19 只羊的组织进行了测试。对于多克隆抗 rNcSRS2 和抗 rTgSRS2 血清，IHC 和 PCR 之间的总体一致性均为 90.1%。多克隆抗血清具有特异性，可以通过 IHC 目视确认原生动物寄生虫，但不如 PCR 检测那么敏感。