Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China.
Department of Chemistry, College of Life and Basic Science, Sichuan Agricultural University, Ya'an 625014, China.
Int J Mol Sci. 2018 Apr 3;19(4):1063. doi: 10.3390/ijms19041063.
is the causative agent of cystic echinococcosis (CE), a widespread parasitic zoonosis. Leucine aminopeptidases (LAPs) of the M17 peptidase family have important functions in regulating the balance of catabolism and anabolism, cell maintenance, growth and defense. In this study, we presented a bioinformatic characterization and experimentally determined the tissue distribution characteristics of LAP (Eg-LAP), and explored its potential value for diagnosis of CE in sheep based on indirect ELISA. Through fluorescence immunohistochemistry, we found that Eg-LAP was present in the tegument and hooks of PSCs, the whole germinal layer and adult worm parenchymatous tissue. Western blotting results revealed that the recombinant protein could be identified using -infected sheep serum. The diagnostic value of this recombinant protein was assessed by indirect ELISA, and compared with indirect ELISA based on hydatid fluid antigen. The sensitivity and specificity rEgLAP-ELISA were 95.8% (23/24) and 79.09% (87/110), respectively, while using hydatid fluid as antigen showed the values 41.7% (10/24) and 65.45% (72/110). This is the first report concerning leucine aminopeptidase from , and the results showed that Eg-LAP belong to M17 peptidase families, and that it is involved in important biological function of . Furthermore, rEg-LAP is appropriate for diagnosing and monitoring CE in sheep in field. Development of a rapid test using rEg-LAP to diagnose sheep CE deserves further study.
棘球蚴病（CE）是一种广泛存在的寄生虫性人畜共患病，其病原体是细粒棘球绦虫。M17 肽酶家族的亮氨酸氨肽酶（LAPs）在调节分解代谢和合成代谢的平衡、细胞维持、生长和防御方面具有重要作用。在本研究中，我们对 LAP（Eg-LAP）进行了生物信息学特征分析，并通过间接 ELISA 实验确定了其组织分布特征，探讨了其在绵羊 CE 诊断中的潜在价值。通过荧光免疫组织化学，我们发现 Eg-LAP 存在于 PSCs 的皮层和钩中，整个生殖层和成虫实质组织中。Western blot 结果表明，该重组蛋白可以被感染的绵羊血清识别。通过间接 ELISA 评估了该重组蛋白的诊断价值，并与基于包虫液抗原的间接 ELISA 进行了比较。rEgLAP-ELISA 的灵敏度和特异性分别为 95.8%（23/24）和 79.09%（87/110），而使用包虫液作为抗原的灵敏度和特异性分别为 41.7%（10/24）和 65.45%（72/110）。这是首次报道细粒棘球绦虫的亮氨酸氨肽酶，结果表明 Eg-LAP 属于 M17 肽酶家族，参与了棘球蚴的重要生物学功能。此外，rEg-LAP 适合用于诊断和监测田间绵羊的 CE。使用 rEg-LAP 开发快速检测方法诊断绵羊 CE 值得进一步研究。
