Key Laboratory on Technology for Parasitic Diseases Prevention and Control, Jiangsu Institute of Parasitic Diseases, Wuxi, Jiangsu, People's Republic of China.
PLoS One. 2012;7(8):e44032. doi: 10.1371/journal.pone.0044032. Epub 2012 Aug 31.
Schistosomiasis japonica remains a real threat to public health in China. The currently used immunodiagnostic assays are sensitive and have a certain degree of specificity, however, they all use complex crude antigens, are based on detection of schistosome-specific antibodies, and have been shown to cross-react with other parasitic diseases. Therefore, these assays cannot be used to evaluate chemotherapy efficacy. The development of highly sensitive and highly specific immunodiagnostic techniques that can monitor the decline of antibodies specific for S. japonica will be extremely valuable as part of the ongoing strategy to control schistosomiasis in endemic areas. Here we report on the identification of unique fraction antigens of soluble egg antigen (SEA) to which the antibodies disappear 7 weeks after effective treatment. Furthermore, we use these SEA fractions to develop a modified assay with both high sensitivity and specificity.
METHODOLOGY/PRINCIPAL FINDINGS: SEA of S. japonicum was fractionated by electrophoresis using 7.5% SDS-PAGE under non-reducing conditions. The SEA fraction antigens to which antibodies were decreased soon after treatment were collected and used as the detection antigens to establish the FA-ELISA. Sera from patients with acute and chronic schistosomiasis infection, healthy people, and those with other parasitic diseases, were used to evaluate their sensitivity and specificity. Furthermore, sera from patients with chronic schistosomiasis infection were evaluated before and after treatment at different time points to evaluate their chemotherapeutic efficacy.
CONCLUSION/SIGNIFICANCE: We demonstrated that this novel FA-ELISA provided high sensitivity and specificity, with very low cross-reactivity, and can serve as an effective tool to determine the efficacy of chemotherapy against S. japonicum.
日本血吸虫病仍然是中国公共卫生的一个现实威胁。目前使用的免疫诊断检测方法具有较高的灵敏度和一定的特异性，但它们都使用复杂的粗抗原，基于检测日本血吸虫特异性抗体，并且已经显示与其他寄生虫病发生交叉反应。因此，这些检测方法不能用于评估化疗效果。开发高灵敏度和高度特异性的免疫诊断技术，能够监测针对日本血吸虫的抗体下降，这将是控制流行地区血吸虫病的持续策略的重要组成部分。在这里，我们报告了鉴定可溶性虫卵抗原（SEA）独特的片段抗原的情况，这些抗原在有效治疗后 7 周内抗体消失。此外，我们使用这些 SEA 片段开发了一种具有高灵敏度和特异性的改良检测方法。
方法/主要发现：采用 7.5%SDS-PAGE 在非还原条件下电泳分离日本血吸虫 SEA，收集治疗后抗体迅速减少的 SEA 片段抗原作为检测抗原，建立 FA-ELISA。用急性和慢性日本血吸虫感染患者、健康人和其他寄生虫病患者的血清评估其敏感性和特异性。此外，还评估了慢性日本血吸虫感染患者在不同时间点治疗前后的血清，以评估其化疗效果。
结论/意义：我们证明，这种新型 FA-ELISA 具有较高的灵敏度和特异性，交叉反应性很低，可作为有效工具，用于确定针对日本血吸虫的化疗效果。
