血吸虫Sj26膜锚定表达DNA疫苗的构建、表达及其免疫原性

目的构建含日本血吸虫相对分子质量为26000的抗原（Sj26GST）基因的膜锚定表达DNA疫苗，观察其免疫BALB／c小鼠后的免疫应答效应。方法用RT—PCR法，以血吸虫成虫RNA为模板，扩增获得Sj26的全长基因。利用重组PCR技术，在Sj26基因的5’端加上编码IL-2的信号肽核苷酸序列，3’端加上编码胎盘碱性磷酸酶的膜锚定序列，然后将其克隆入pIRES载体中，构建一个膜锚定型真核表达质粒pIRES-Sj26。将重组质粒转染HeLa细胞，通过RT—PCR及间接免疫荧光技术检测目的基因的表达。用构建的pIRES-Sj26疫苗肌肉注射免疫BALB／c小鼠后，以ELISA试剂盒检测小鼠血清中的总IgG抗体浓度，脾细胞培养法检测脾淋巴细胞培养上清的干扰素γ（INF-γ）含量，淋巴细胞刺激指数（SI）反映淋巴细胞增殖能力，流式细胞术检测脾细胞CD4／CD8亚群。结果经过酶切鉴定、PCR及测序证实重组质粒pIRES-Sj26构建成功，经转染HeLa细胞及免疫荧光检测证明质粒pIRES-Sj26能在体外进行表达。免疫小鼠后检测结果表明pIRES-Sj26组的血清总IgG抗体浓度、INF-γ的含量明显高于空白对照组和空载体组（均P〈0．01）；其脾SI高于空白对照组和空载体组（P〈0．05）；CD8^＋细胞百分比高于空白对照组和空载体组（均P％0．05），CD4^＋细胞百分比没有显著变化（P〉0．05）。结论成功构建日本血吸虫膜锚定表达DNA疫苗pIRES-Sj26，表达的Sj26蛋白大部分锚定在细胞膜上。pIRES—Sj26疫苗能增强BALB／c小鼠的免疫应答反应。     

血吸虫多基因非融合性膜锚定表达疫苗的研究

目的 构建日本血吸虫多基因非融合性膜锚定表达疫苗pIRES-Sj97-Sj14-Sj26,并研究其免疫原性及免疫保护作用。 方法 构建日本血吸虫脂肪酸结合蛋白（Sj14）、谷胱甘肽-S-转移酶（Sj26）和副肌球蛋白（Sj97）的跨膜共表达质粒pIRES?鄄Sj97-Sj14-Sj26,转染HeLa细胞。通过RT?鄄PCR法检测Sj14、Sj26和Sj97 mRNA的表达,免疫荧光（IFA）检测Sj14、Sj26和Sj97蛋白的表达。用纯化的该质粒免疫BALB／c小鼠（100 μg/只）,设生理盐水和空载体对照组,20只/组,每隔2周加强免疫1次,共免疫3次。末次免疫2周后,每组取10只小鼠,眼球取血并断颈处死,取脾淋巴细胞及腹腔巨噬细胞。分别检测免疫小鼠血清中总IgG抗体及脾淋巴细胞培养上清干扰素-γ（IFN-γ）水平,淋巴细胞刺激指数（SI）及 NO释放量,并分析脾淋巴细胞亚群。各组中余下小鼠每只经腹部感染40±1条尾蚴,45 d后剖杀,计数成虫数及肝卵数,计算减虫率和减卵率。结果 构建的质粒可在体外表达。疫苗组、生理盐水组和空白质粒组血清总IgG抗体含量分别为（5.62±0.64）、 （1.22±0.20）及（1.48±0.36） mg/ml,疫苗组与各对照组差异均具有统计学意义（P<0.01, P<0.05）。疫苗组、生理盐水组和空白质粒组小鼠腹腔巨噬细胞NO含量分别为（321.19±18.03）、 （184.12±11.05）及（213.51±15.93） nmol/ml,疫苗组与生理盐水组间差异有统计学意义（P<0.05）。疫苗组、生理盐水组、空白质粒组小鼠脾淋巴细胞刺激指数分别为（2.25±0.29）、（1.18±0.07）及（1.22±0.09）,疫苗组显著升高（P<0.01）。疫苗组INF-γ水平与各对照组相比,差异具有统计学意义（P<0.01）;CD4+和CD8+T细胞百分比明显升高。疫苗组减虫率和肝减卵率分别为39.9％和43.94％。 结论 pIRES-Sj97-Sj14-Sj26疫苗具有较强的免疫原性,可对日本血吸虫感染的小鼠产生一定保护作用。     

Construction and Expression of DNA Vaccine pIRES-Sj97-Sj14-Sj26 and Its Immunogenicity in Mice

To find a new preventive strategy for the infection of Schistosoma japonica, plasmid pIRES-Sj97-Sj 14-Sj26 that contains fatty binding protein （Sj 14）, GST （Sj26） and paramyocin （Sj97） that are expressed on the membrane, was constructed. RT-PCR was used to detect the expression of Sj 14 mRNA, Sj26 mRNA and Sj97 mRNA in the Hela cells, the indirect immunofluorescent test was employed for the detection of the expression of trans-membrane Sj26 after the plasmid was transfected into Hela cells. Fifty BALB/c mice were randomly divided into 5 groups and plRES-Sj97-SjI4-Sj26 plasmid DNA, plRES-Sj 14-Sj26 plasmid DNA, plRES-Sj26 plasmid DNA, plRES blank vector and normal saline were respectively injected into the quadriceps muscles of thigh Eight weeks after the immunization the mice were killed and significantly higher level of IgG was detected in the plRES-Sj97-Sj 14-Sj26 group as compared with the plRES blank vector, normal saline and plRES-Sj26 groups （P〈 0.01） and the plRES-Sj 14-Sj26（P〈0.05）. Single splenocyte suspension was prepared to detected the level of IFN-T by ELISA and the lymphocyte stimulating index （SI） by MTT. SI was significantly higher of in the plRES-Sj97-Sj 14-Sj26 group than in other groups （P〈 0.01）, while the IFN-T level was significantly higher the plRES-Sj97-Sj 14-Sj26 group than in plRES blank vector and normal saline groups （P〈0.01）, but no significant differences were found when compared with plRES-Sj 14-Sj26 and plRES-Sj26 groups. Flow cytometery showed that the percentages of CD4＋ and CD8＋ T cells were much higher in the plRES-Sj97-Sj 14-Sj26 group （P〈 0.01, P〈0.05）. It was concluded that plRES-Sj97-Sj 14-Sj26 vaccine may induce stronger immune response in BALB/c mice.     

人结核杆菌热休克蛋白65和Ag85A基因真核双表达质粒的构建和体外表达

目的构建人结核杆菌热休克蛋白65（Hsp65）与Ag85A基因的共表达载体pIRES-Hsp65-Ag85A,并检测其在体外的表达。方法利用聚合酶链反应（PCR）法及基因重组技术,以人结核杆菌基因组DNA为模板,扩增获得Hsp65与Ag85A的全长基因,并将其构建到真核表达质粒pIRES中获得共表达质粒pIRES-Hsp65-Ag85A。将该质粒转染Hela细胞,通过RT-PCR的方法检测目的基因的表达。结果经过测序证实重组质粒构建成功,该质粒在体外转染Hela细胞后可表达Hsp65与Ag85A两者的mRNA。结论成功构建了共表达质粒pIRES-Hsp65-Ag85A,该质粒能在人子宫颈癌细胞中表达。