日本血吸虫基因重组抗原rSj06868对小鼠的免疫保护效果

为克隆、表达日本血吸虫假想蛋白SJCHGC068068编码基因（暂命名为Sj06868）并观察重组抗原的免疫预防效果。应用PCR技术从日本血吸虫7 d童虫、14 d童虫mRNA反转录制备的cDNA中克隆到Sj06868基因的46-438 bp DNA片段,BLASTn分析未发现其他物种中的同源性序列,也未发现其保守序列和相关功能结构域。以pET32a为表达载体、Sj06868基因在大肠杆菌Rosetta（DE3）中获得高效表达,表达产物rSj068068分子量为36 kDa,能被感染血吸虫14 d兔血清识别。将纯化的重组抗原与佐剂ESSAI ISA 206 CELL混合后免疫BALB/c小鼠,与佐剂对照组和PBS对照组相比,分别获得了31.63%、29.19%减虫率以及55.63%、56.27%肝脏虫卵减少率。用ELISA检测各组血清中抗rSj068068特异性抗体结果显示,免疫组在攻击感染前、佐剂对照组和PBS对照组在感染后均产生了较高水平的特异性抗体。本研究结果说明,Sj068068是日本血吸虫特有的童虫期高表达基因,rSj068068在抗血吸虫疫苗和血吸虫感染的诊断方面均有潜在应用价值。

PROTECTIVE IMMUNITY INDUCED BY A RECOMBINANT ANTIGEN RSJ06868 OF SCHIISTOSOMA JAPONICUM

To express the hypotheticial protein SJCHGC068068（gene was named as Sj06868） of Schistosoma japonicum（S.japonicum）,and evaluate immune efficacy of the recombinant antigen in mice against Schistosomiasis,the 46-438 nt of Sj06868 was amplified by PCR from 7 d or 14 d Schistosomula.BLASTn analysis revealed that there were no conserved regions and motifs in the derived protein and no similar sequences of other species.This gene was subsequently cloned into the expression vector pET32a and expressed in E.coli Rosetta（DE3）.The recombinant protein rSj068068 was a 36 kDa fusion protein,which could be recognized in Western blot by S.japonicum-infected rabbit sera.The purified recombinant protein was used to vaccinate BALB/c mice with ESSAI ISA 206 CELL as adjuvant.Worm reductions of 31.63% and 29.19%,and hepatic egg reductions of 55.63% and 56.27% were recorded in immunized group comparing with PBS and adjuvant control groups,respectively.There was significant increase of total IgG antibody response against rSj068068 in vaccinated group before challenge and control groups after challenge.These results indicated that Sj068068 was a peculiar gene of S.japonicum and highly expressed in schistosomula,and the recombinant protein has good potential for further studies on vaccine development and diagnosis.