日本血吸虫丝氨酸-苏氨酸蛋白磷酸酶基因的表达及其免疫保护试验

Expression and protective immunity of serine-threonine specific protein phosphatase SjPP of Schistosoma japonicum

为研究日本血吸虫丝氨酸-苏氨酸蛋白磷酸酶(SjPP)的免疫功能,构建了原核表达重组质粒pET28a(+)-SjPP,转化大肠埃希氏菌BL21(DE3)进行诱导表达,并用重组蛋白进行了小鼠免疫保护试验,免疫剂量为每次20μg/只,共免疫3次。结果表明,pET28a(+)-SjPP/BL21(DE3)在0.1 mmol/L IPTG诱导2 h时,每1 g菌体可产生17.8 mg以包涵体形式存在的重组蛋白;重组蛋白免疫小鼠后诱导产生了高效价的血清特异性IgG抗体,并获得了部分减虫率、肝组织减卵率和显著的粪便减卵率,具有一定的免疫保护作用。

A serine-threonine specific protein phosphatase gene of Schistosoma japonicum, SjPP, was cloned into pET28a（＋） to construct a recombinant plasmid pET28a（＋）-SjPP. The plasmid pET28a（＋）- SjPP in E. coli strain BL21 （DE3） was induced with 0.1 mmol/L of IPTG and expressed in inclusion bodies. Production of the recombinant protein rSjPP was 17.8 mg per gram of bacteria after induction for 2 h. The purified recombinant proteins were used to vaccinate BALB/c mice to evaluate immunoprotective efficacy. The mice in vaccination group were immunized with 20 μg rSjPP emulsified with Freund＇s complete adjuvant（FCA）, and those in adjuvant or blank control groups were injected with FCA/FIA or PBS, respectively on week 0, 2, 4. The mice were challenged with cercariae on week 2 after the final injection, and were sacrificed on day 42 after challenge. High titre specific anti-rSjPP antibody IgG was observed in the sera of vaccinated mice, and partial worm reduction, hepatic tissue egg reduction, and significant faecal egg reduction were obtained in vaccinated group, when comparied with that in the blank control group.