Hassan M M, Nasr M E, Mowafy N M, Mostafa N A, El-Mahrouky F
Department of Parasitology, Faculty of Medicine, Zagazig University, Egypt.
J Egypt Soc Parasitol. 1999;29(1):49-57.
Monoclonal antibody 128C3/3/21 in an antigen-capture ELISA was used to detect circulating antigen in individuals infected with Schistosoma mansoni. This antibody recognizes a carbohydrate epitope expressed on the major group of acidic egg glycoproteins and on glycoproteins and glycolipids in all other stages of parasite development. The overall sensitivity of the assay was 78%, with a sensitivity of 100% for patients excreting >100 egg/g feces (EGF) and 72% for those excreting <100 EGF. By increasing the degree of antibody biotinylation, the authors have now achieved sensitivities of 92.4% overall and 82% for those excreting <100 EGF. A direct increase in the mean level of circulating antigen was found with increasing egg counts. The difference between those excreting >100 EGF (53 individuals) and those excreting <100 EGF (39 cases) was statistically significant (P<0.01). None of the control sera (23 uninfected individuals and 16 patients infected with other parasites) had circulating antigen levels >80 ng/ml. Thus, the test specificity was >99%. The test accuracy was 94.7%, the positive predictive value 100%, and the negative predictive value 84.8%.
在抗原捕获酶联免疫吸附测定（ELISA）中，单克隆抗体128C3/3/21被用于检测曼氏血吸虫感染个体的循环抗原。该抗体识别主要酸性虫卵糖蛋白以及寄生虫发育所有其他阶段的糖蛋白和糖脂上表达的碳水化合物表位。该检测方法的总体灵敏度为78%，对于每克粪便虫卵排出量>100个（EGF）的患者灵敏度为100%，对于每克粪便虫卵排出量<100个EGF的患者灵敏度为72%。通过提高抗体生物素化程度，作者目前已实现总体灵敏度为92.4%，对于每克粪便虫卵排出量<100个EGF的患者灵敏度为82%。发现随着虫卵计数增加，循环抗原平均水平直接升高。每克粪便虫卵排出量>100个EGF的患者（53例）与每克粪便虫卵排出量<100个EGF的患者（39例）之间的差异具有统计学意义（P<0.01）。对照血清（23例未感染个体和16例感染其他寄生虫的患者）中无一例循环抗原水平>80 ng/ml。因此，检测特异性>99%。检测准确性为94.7%，阳性预测值为100%，阴性预测值为84.8%。
