日本血吸虫Rho GTPase DNA疫苗及重组蛋白疫苗免疫保护机制初探

STUDY ON MECHANISM OF PROTECTIVE IMMUNITY OF SCHISTOSOMA JAPONICUM Rho GTPase DNA VACCINE AND RECOMBINANT VACCINE

目的 初步探讨日本血吸虫中国大陆株pcDNA3 .1 SjRhoGTPaseDNA疫苗、重组蛋白疫苗以及联合疫苗免疫的保护机制。 方法 将 pcDNA3 .1 SjRhoGTPaseDNA疫苗、重组蛋白疫苗分别及联合疫苗免疫昆明鼠后 ,分不同时间采集血清 ,以ELISA法测定总抗体及IgG亚类。 结果 重组蛋白疫苗及联合疫苗诱导产生的抗体效价较高 ,DNA疫苗及联合疫苗诱导产生的抗体以IgG2a为主 ,重组蛋白疫苗诱导产生的抗体以IgG1为主。 结论 Sj RhoGTPase基因DNA疫苗及联合疫苗主要诱生Th1型细胞免疫应答 。

Objective To explore the mechanism of the protective immunity of Schistosoma japonicum(Sj) Rho GTPase DNA vaccine and recombinant vaccine. Methods Kunming mice were immunized with pcDNA3.1-SjRho GTPase DNA vaccine or recombinant protein vaccine rGST-SjRho GTPase. The mouse sera were collected from the tail vein before every immunization or before challenge. The antibody IgG, IgG1 and IgG2a to Sj-Rho GTPase were detected by ELISA. Results Compared with control groups, vaccination with rGST-Sj-Rho GTPase alone or with DNA priming-protein boosting stimulated high levels of IgG in mice after the third immunization, whereas, the vaccination with DNA alone stimulated low levels of IgG. The titres of specific IgG in sera collected just before challenge researched 1∶25 600(group C, recombinant protein alone) and 1∶1 600(group D, DNA vaccination alone) and 1∶102 400(group E, DNA priming-protein boosting regimen) respectively. The isotype profile of the response differed also between the groups. Thus protein alone and DNA priming-protein boosting vaccination resulted in the induction of high levels of IgG1, which was 1∶25 600 in both groups. Meanwhile, DNA vaccination or DNA priming-protein boosting vaccination resulted in the induction of IgG2a. The IgG2a titre in the former was 1∶1 600 and in the later was 1∶51 200. Conclusion Th1 immune responses was induced by Sj-Rho GTPase DNA vaccine or DNA-priming and protein-boosting regimen, and Th2 immune response was induced by recombinant protein vaccine.