肺吸虫模拟抗原诊断价值及序列分析

目的　探讨噬菌体展示肺吸虫模拟抗原的诊断价值并分析与天然抗原的同源性。方法　建立肺吸虫噬菌体模拟抗原的ELISA ,对肺吸虫病人、日本血吸虫病人、旋毛虫病人及健康者血清进行检测 ,分析其敏感性和特异性 ;提纯噬菌体模拟肽的DNA模板进行序列测定 ,以Blast软件分析其序列同源性。结果　肺吸虫模拟抗原的 6个阳性克隆中P5、P6、P8、P13、P16的阳性、阴性预测值及诊断效率均为 10 0 % ,P7的阳性、阴性预测值及诊断效率分别为 10 0 %、78.9%、86.7%。上述 6个克隆有 2个克隆的DNA序列完全相同 ,即 6个克隆包含了 5种不同的抗原表位 ;Blast分析表明 5个表位与已知的肺吸虫抗原表位无DNA序列的同源性。结论　肺吸虫模拟抗原对肺吸虫病具有一定的诊断价值 ,这 5种表位可能从空间结构上模拟了天然抗原表位。

Study on Diagnostic Value and Sequence of Mimic Antigen of Paragonimus

Objective To study the diagnostic value of mimic antigen of paragonimus and analyze the sequence homology between the mimic antigen and the natural antigen. Methods The phage displayed antigens of paragonimus were used to examine the sera of patients with paragonimiasis,schistosomiasis,trichinosis and healthy people, and their sensitivity and specificity were acquired; The templates of the mimic antigen were purified to determine the sequence and the sequence homology was analyzed by Blast. Results In the six mimic antigens(P5,P6,P7,P8,P13 and P16), the positive expectation, the negative expectation and the diagnostic efficiency of P5,P6,P8,P13 and P16 were all 100%, for P7 was 100%, 78.9% , 86.7% , respectively. Two of the six clones had the same DNA sequence, so there are five different antigenic epitopes in the six clones; the Blast analysis showed that there were no sequence homology between the five epitopes and the known antigen of paragonimus. Conclusion The mimic antigen of paragonimus had definite diagnostic value in the paragonimiasis, and the five epitopes may mimic the natural antigen in the special structure.