Nuamtanong Supaporn, Dekumyoy Paron, Adisakwattana Poom
Department of Helminthology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
Southeast Asian J Trop Med Public Health. 2012 Sep;43(5):1094-104.
Serine protease inhibitors, known as serpins, are mainly expressed in newborn and early-stage Trichinella spiralis larvae, suggesting that T. spiralis serpin (TsSERP) could be used as antigen for the immunodiagnosis of swine trichinosis. We produced His-tagged recombinant TsSERP (rTsSERP) in Escherichia coli and purified it using a Co(2+)-affinity column. Western blot (WB) and enzyme-linked immunosorbent assay (ELISA) were performed to determine T. spiralis-infected swine sera samples (n = 5), negative controls (n = 26), and other parasite-infected samples (n = 83). WB showed that T. spiralis-infected sera initially reacted with rTsSERP at day 6 post-infection (dpi), and more strongly in late infection (62 and 84 dpi). However, other parasite-infected sera also elicited cross-reactivity to rTsSERP. On the other hand, indirect ELISA showed that TsSERP was an appropriate antigen for detecting late (> 60 dpi) but not early infection. No cross-reaction was observed with other parasite-infected sera. Sensitivity and specificity of TsSERP-ELISA at 62 dpi was 80% and 100%, respectively, and at 84 dpi 100% and 100%, respectively. These preliminary results show that TsSERP-ELISA method is suitable for the diagnosis of swine trichinosis, and could become the standard test for diagnosis of trichinosis in several hosts, including humans.
丝氨酸蛋白酶抑制剂，即丝氨酸蛋白酶抑制蛋白，主要在旋毛虫新生幼虫和幼虫早期阶段表达，这表明旋毛虫丝氨酸蛋白酶抑制蛋白（TsSERP）可作为猪旋毛虫病免疫诊断的抗原。我们在大肠杆菌中生产了带有组氨酸标签的重组TsSERP（rTsSERP），并使用钴离子亲和柱进行纯化。采用蛋白质印迹法（WB）和酶联免疫吸附测定法（ELISA）对旋毛虫感染猪血清样本（n = 5）、阴性对照（n = 26）以及其他寄生虫感染样本（n = 83）进行检测。WB结果显示，旋毛虫感染血清在感染后第6天（dpi）开始与rTsSERP发生反应，在感染后期（62和84 dpi）反应更强。然而，其他寄生虫感染血清也与rTsSERP产生交叉反应。另一方面，间接ELISA结果表明，TsSERP是检测旋毛虫晚期感染（> 60 dpi）而非早期感染的合适抗原。未观察到与其他寄生虫感染血清的交叉反应。TsSERP-ELISA在62 dpi时的敏感性和特异性分别为80%和100%，在84 dpi时分别为100%和100%。这些初步结果表明，TsSERP-ELISA方法适用于猪旋毛虫病的诊断，并可能成为包括人类在内的多种宿主旋毛虫病诊断的标准检测方法。
