Zhang W-B, Li J, Li Q, Yang D, Zhu B, You H, Jones M K, Duke M, McManus D P
Molecular Parasitology Laboratory, Australian Centre for International and Tropical Health and Nutrition, The Queensland Institute of Medical Research and The University of Queensland, Brisbane, Queensland, Australia.
Clin Exp Immunol. 2007 Jul;149(1):80-6. doi: 10.1111/j.1365-2249.2007.03386.x. Epub 2007 Apr 2.
An Echinococcus granulosus cDNA sequence coding for EpC1, a proven serodiagnostic marker for cystic echinococcosis (CE, hydatid disease), has high amino acid sequence identity to a paralogue from Taenia solium, the cause of neurocysticercosis (NCC). To determine diagnostic antibody-binding regions on EpC1 recognized specifically by CE sera, 10 truncated regions (P1-10) of the immunogenic protein were expressed in Escherichia coli and subjected to immunoblotting. One peptide, designated peptide 5 [P5, fused with glutathione-S-transferase (GST)] was positively recognized by sera from mice experimentally infected with oncospheres of E. granulosus and sera from surgically confirmed CE patients. Sera from NCC patients did not react with any of the peptides used. There are four amino acid substitutions in P5 compared with the T. solium sequence and these may form part of the epitope inducing CE-specific antibody. Ninety-seven per cent (58 of 60) of sera from confirmed CE patients recognized P5-GST, which was higher than the parent EpC1 fused with GST which reacted with 92% (55 of 60) of the sera. A population screening survey showed that 424 human sera collected from communities in Xinjiang, an area in China endemic for CE, exhibited 4.5% and 3.3% positivity in immunoblotting analysis to EpC1 and P5, respectively; 19.8% of these sera reacted positively against hydatid cyst fluid (HCF) antigen B. Low numbers of surgical CE cases have been reported from this population, suggesting that HCF-based serology lacks specificity and that EpC1 or its contained P5 peptide may prove more accurate for seroepidemiological surveys of CE.
编码EpC1的细粒棘球绦虫cDNA序列是囊性棘球蚴病(CE,包虫病)经证实的血清学诊断标志物,它与猪带绦虫(神经囊尾蚴病(NCC)的病原体)的一个旁系同源物具有高度的氨基酸序列同一性。为了确定CE血清特异性识别的EpC1上的诊断性抗体结合区域,在大肠杆菌中表达了免疫原性蛋白的10个截短区域(P1 - 10),并进行免疫印迹分析。一种名为肽5 [P5,与谷胱甘肽 - S - 转移酶(GST)融合] 的肽被实验性感染细粒棘球绦虫六钩蚴的小鼠血清和手术确诊的CE患者血清阳性识别。NCC患者的血清与所使用的任何肽均无反应。与猪带绦虫序列相比,P5中有四个氨基酸替换,这些可能构成诱导CE特异性抗体的表位的一部分。确诊的CE患者血清中有97%(60份中的58份)识别P5 - GST,高于与92%(60份中的55份)血清反应的与GST融合的亲本EpC1。一项群体筛查调查显示,从中国CE流行地区新疆的社区收集的424份人血清在免疫印迹分析中对EpC1和P5的阳性率分别为4.5%和3.3%;其中19.8%的血清对包虫囊肿液(HCF)抗原B呈阳性反应。该人群中报告的手术确诊CE病例数量较少,这表明基于HCF的血清学缺乏特异性,并且EpC1或其包含肽P5可能在CE的血清流行病学调查中更准确。