【摘要】 目的研究日本血吸虫复合表位DNA疫苗诱导BALB/c小鼠抗血吸虫感染的免疫保护作用。方法将40只雌性BALB/c小鼠随机分为4组:pcDNA3.1组(对照组),每鼠经两侧股四头肌注射100μg pcDNA3.1质粒DNA,每侧50μg;TPI组,每鼠肌注100μg pcDNA3.1-TPI质粒DNA;TP组,每鼠肌注100μg pcDNA3.1-T-linker-P质粒DNA;PT组,每鼠肌注100μg pcDNA3.1-P-linker-T质粒DNA。每隔2周加强免疫1次,剂量和方法相同,共免疫3次。末次免疫后4周每鼠经腹部皮肤攻击感染(45±1)条日本血吸虫尾蚴,45d后剖杀,计数成虫及肝脏虫卵数。首次免疫前2 d及感染前2 d尾静脉采血,间接ELISA检测特异IgG及IgG1I、gG2a水平。末次免疫后3周,每组取2只小鼠制备脾细胞,双抗体夹心法检测脾细胞经ConA和rSjCTPI刺激后培养上清中的IL-2I、L-4和IFN-γ水平。结果TP组和PT组小鼠减虫率分别为34.76%和36.14%,显著高于TPI组(P<0.05)和对照组(P<0.01);减卵率分别为51.20%和50.79%,与TPI及对照组比较差异有显著性(P<0.05)。TP组和PT组小鼠血清特异性IgG水平均升高(P<0.05),IgG2a/IgG1的比值分别为4.23和4.34。脾细胞经ConA和rSjCTPI刺激后,IL-2水平TP组和PT组较对照组均升高。结论复合表位DNA疫苗能诱导小鼠产生抗血吸虫感染的免疫保护力,效果优于rSjCTPI疫苗。更多还原

【Abstract】 Objective To study the protective efficacy of multi-epitope DNA vaccine against Schistosoma japonicum infection in BALB/c mice. Methods Forty female BALB/c mice were randomly divided into 4 groups.In pcDNA3.1 group（control group）,each mouse was immunized with 100 μg of pcDNA3.1 plasmid DNA by intramuscular injection;In TPI group,each mouse was immunized with 100 μg of pcDNA3.1-TPI plasmid DNA;In TP group,each mouse was immunized with 100 μg of pcDNA3.1-T-linker-P plasmid DNA;In PT group,each mouse was immunized with 100 μg of pcDNA3.1-P-linker-T.All animals were boosted at week 2 and week 4.Four weeks after the 3rd immunization,all mice were challenged with 45±1 cercariae of S.japonicum by abdominal skin penetration.45 days post-challenge,mice were perfused and the numbers of recovered worms and hepatic eggs were counted.Blood was collected from the tail vein of all mice 2 days before the 1st immunization and challenge respectively.Serum was prepared for detection of IgG,IgG₁ and IgG_2a by indirect ELISA.Three weeks after the 3rd inoculation,the spleen cells of 2 mice from each group were cultured and stimulated with ConA and rSjCTPI.The supernatant was collected to detect IL-2,IL-4,IFN-γ by DAB sandwich.Results The worm reduction rates in TP group and PT group were 34.76% and 36.14%,the hepatic egg reduction rates were 51.20% and 50.79% respectively compared with control group.The level of protection in TP group was equal that in PT group（P>0.05）.ELISA results indicated that mice immunized with pcDNA3.1-T-linker-P and pcDNA3.1-P-linker-T produced specific IgG to rSjCTPI,while mice immunized with pcDNA3.1 did not.Mice in TP group and PT group also produced IgG1 and IgG2a antibody isotypes,with the ratios of IgG2a/IgG1 4.23 and 4.34 respectively.In comparison with control,the levels of IL-2 and IFN-γ of mice immunized with pcDNA3.1-T-linker-P and pcDNA3.1-P-linker-T were augmented.Conclusion This study indicates that multiepitope DNA vaccine could induce protective immunity in BALB/c mice significantly.The effect is stronger than that by rSjCTPI DNA vaccine,and is obviously correlated with Th1 type responses.更多还原