中文摘要：

目的研究日本血吸虫硫氧还蛋白谷胱甘肽还原酶（Thioredoxin Glutathione Reductase of Schistosoma japonicum,SjTGR）的免疫原性及抗日本血吸虫感染的免疫保护性作用。方法 75只小鼠随机分为5组：空白组、PBS组、CpG2免疫组、TGR免疫组和TGR＋CpG2联合免疫组,免疫3次。首次免疫前及第3次免疫后2周经尾静脉采血,采用酶联免疫法分别检测血清中抗SjTGR蛋白IgG、IgG1和IgG2a的抗体水平。第3次免疫后2周,每只小鼠经腹部感染日本血吸虫尾蚴40±2条,42 d后剖杀,收集成虫和虫卵,计算减虫率和减卵率;制备各组小鼠单个脾淋巴细胞,采用流式细胞术检测脾细胞表面标志物CD44high、CD4＋CD44high或CD8＋CD44high水平;用SjTGR刺激免疫小鼠脾细胞72 h,采用酶联免疫法检测脾细胞的IL-2、IL-4、IL-10和IFN-γ的水平。结果第3次免疫后2周TGR与CpG2＋TGR免疫组小鼠血清抗SjTGR抗体的IgG滴度均达1：200 000以上,IgG2a与IgG1的比值（IgG2a/IgG1）随时间的延长缓慢增高。TGR免疫组和TGR＋CpG2联合免疫组细胞上清中的IFN-γ和IL-2水平与空白组、PBS组、CpG2免疫组相比明显增高（P〈0.05）。TGR免疫组与TGR＋CpG2免疫组小鼠脾细胞的CD44high、CD8＋CD44high及CD4＋CD44high与空白组和PBS组相比细胞比值增加（P〈0.05）。TGR免疫组和CpG2＋TGR免疫组的减虫率分别为9.4%,10.5%,减卵率分别为9.2%和32.8%。结论 SjTGR具有较强的免疫原性,可诱导小鼠免疫反应向Th1型极化,但不足以产生抗日本血吸虫感染的保护效应。CpG2 ODN可能是一种有效的Th1型免疫佐剂。

英文摘要：

Objective To study the immunogenicity and the immuno-protection of thioredoxin glutathione reductase from Schistosoma japonicum（SjTGR）against schistosome infection in mice. Methods Seventy-five mice were randomly divided into 5 groups,namely,blank group,PBS group,CpG2 immunized group,TGR immunized group and TGR ＋ CpG2 co-immunized group. Each mouse was immunized for 3 times. The mice were tail bled before the first immunization and 2 weeks after the third immunization. The serum antibody levels of total IgG,IgG1 and IgG2 a against SjTGR were assayed by ELISA.Two weeks after the third immunization,each mouse was infected with 40±2 S. japonicum cercariae by abdominal skin penetration. Forty-two days later,all the mice were sacrificed to collect schistosome adult worms and liver eggs. The worm and egg reduction rates were calculated respectively. The single splenocyte of mouse was collected 2 weeks after the third immunization,and the expressions of CD44 high,CD4＋CD44highor CD8＋CD44highon splenocytes of mice were examined by flow cytometry. After 72 h incubation with recombinant SjTGR,the levels of IL-2,IL-4,IL-10,and IFN-γ in the single-cell supernatant were determined by using ELISA kit. Results Two weeks after the third immunization,the titers of serum IgG against SjTGR in mice immunized with SjTGR and co-immunized with SjTGR and CpG2 were higher than 1：200 000. The IgG2 a ：IgG1 ratio（IgG2a/IgG1）increased slowly with time in both TGR immunized group and TGR ＋ CpG2 co-immunized group.There were obviously higher levels of IFN-γ and IL-2 in the cell supernatant in the TGR immunized group and TGR ＋ CpG2co-immunized group compared to the blank,PBS and CpG2 groups（P〈0.05）. The increased subpopulations of CD44 high,CD8＋CD44highand CD4＋CD44highcells in the splenocytes from mice immunized by SjTGR and co-immunized by SjTGR and CpG2 were found comparing to the blank,PBS and CpG2 groups（P〈0.05）. The TGR immunization and TGR ＋ CpG2 coimmunization caused 9.4% and 10.5% reductions in