Ikeda T, Oikawa Y, Nishiyama T
Department of Medical Zoology, Kanazawa Medical University, Ishikawa, Japan.
Am J Trop Med Hyg. 1996 Oct;55(4):435-7.
An enzyme-linked immunsorbent assay (ELISA) using worm extract antigens from lung flukes of Paragonimus westermani provided good sensitivity to sera from patients with paragonimiasis westermani but high cross-reactivity with sera from most fascioliasis patients and some patients with onchocerciasis or clonorchiasis. To improve the specificity, we tested an ELISA using fluke cysteine proteinases as antigens. Cysteine proteinases were partially purified from the excretory/secretory products of P. westermani by 40-75% ammonium sulfate fractionation, hydrophobic chromatography, and arginine affinity chromatography. An ELISA using the enzyme preparation not only had increased sensitivity to paragonimiasis westermani sera but also reduced cross-reactivity with the fascioliasis, onchocerciasis, and clonorchiasis sera to negligible levels. The reactivity of the ELISA to paragonimiasis miyazakii sera was similar to that of paragonimiasis westermani sera. A proteinase preparation from P. ohirai, which can be obtained easily from infected rats, provided similar results. Therefore, the ELISA using cysteine proteinases of Paragonimus could not distinguish the parasite species with which patients were infected, but it is a valuable assay with which to immunodiagnose paragonimiasis even when the proteinases are prepared from nonhuman species.
使用卫氏并殖吸虫肺吸虫虫体提取物抗原的酶联免疫吸附测定（ELISA）对卫氏并殖吸虫病患者血清具有良好的敏感性，但与大多数肝片吸虫病患者以及一些盘尾丝虫病或华支睾吸虫病患者的血清存在较高的交叉反应性。为提高特异性，我们检测了一种使用吸虫半胱氨酸蛋白酶作为抗原的ELISA。半胱氨酸蛋白酶通过40%-75%硫酸铵分级沉淀、疏水色谱和精氨酸亲和色谱从卫氏并殖吸虫的排泄/分泌产物中部分纯化得到。使用该酶制剂的ELISA不仅对卫氏并殖吸虫病血清的敏感性增加，而且与肝片吸虫病、盘尾丝虫病和华支睾吸虫病血清的交叉反应性降低到可忽略不计的水平。该ELISA对宫崎并殖吸虫病血清的反应性与卫氏并殖吸虫病血清相似。从感染大鼠中容易获得的大平并殖吸虫蛋白酶制剂也得到了类似结果。因此，使用并殖吸虫半胱氨酸蛋白酶的ELISA无法区分患者感染的寄生虫种类，但即使蛋白酶是从非人类物种制备的，它也是一种用于并殖吸虫病免疫诊断的有价值的检测方法。
