Abstract: Objective To obtain the prokaryotic expression of transketolase genes and analyze its value as a diagnostic antigen for echinococcosis. Methods TK gene was amplified by PCR and cloned into prokaryotic vector pMD19?EgTK， and then subcloned into the expression vector pET?28a. The target gene TK prokaryotic expression plasmid pET?28a was constructed and transferred into BL21. The purified protein was identified by SDS?PAGE and Western blotting. The blood samples of patients with cystic echinococcosis （CE group）， alveolar echinococcosis （AE group） and healthy people （healthy group） were collected and detected by ELISA with the recombinant EgTK protein as a diagnostic antigen. Results The recombinant plasmid pET?28a（+）?EgTK was constructed successfully， and there was a band around 70 kDa by using Western blotting. ELISA showed that the difference among the 3 groups of sera reaction A450 was significantly different （F = 44.47， P < 0. 01）， and the A450 values of the CE group （1.46±0.41） and AE group （1.28±0.29） were higher than that of the healthy group （[0.66±0.23]）， but there was no significant difference between the former two. Conclusion The recombinant EgTK protein is better to distinguish the echinococcosis group and healthy group， but it can’t do a differential diagnosis between CE and AE cases.

Key words: Echinococcus granulosus； Echinococcosis； Transketolase； Recombinant plasmid； Diagnostic antigen

摘要： 目的 通过原核表达获得细粒棘球绦虫转酮醇酶（TK）表达产物，分析其作为棘球蚴病诊断抗原分子的价值。方法 PCR扩增TK基因，克隆至原核载体pMD19?EgTK，随后亚克隆至表达载体pET?28a，构建目的基因TK原核表达质粒pET?28a（+）?EgTK，转入大肠埃希菌BL21，分离纯化蛋白，经SDS?PAGE、Western blotting鉴定后，收集细粒棘球蚴病（CE组）、多房棘球蚴病（AE组）患者及健康人（健康组）血清，以酶联免疫吸附试验（ELISA）检测重组蛋白作为诊断抗原的价值。结果 成功构建pET?28a（+）?EgTK质粒，经SDS?PAGE和Western blotting分析，EgTK蛋白在70 kDa处出现条带，与理论值一致。ELISA显示，CE组、AE组和健康组血清反应吸光度A450值间差异有统计学意义（F = 44.47，P < 0.01），CE组（1.46±0.41）、AE组A450值（1.28±0.29）高于健康组（0.66±0.23）（P ＜ 0.05），但CE组和AE组间A450值差异无统计学意义（P＞ 0.05）。结论 重组TK分子可较好地区分棘球蚴病患者和非棘球蚴病患者，但无法区分细粒棘球蚴病和多房棘球蚴病患者。

关键词: 细粒棘球绦虫；棘球蚴病；转酮醇酶；重组质粒；诊断抗原