用于大容量人源天然噬菌体抗体库的表达载体的构建及鉴定

目的构建一个应用于大容量Fab段天然噬菌体抗体库的表达载体。方法用定点突变技术将表面呈现噬菌粒载体pDF上的BssHⅡ酶切位点改为BglⅡ酶切位点,然后分别在抗体轻链和重链位置插入自杀基因SacB,构建含自杀基因的噬菌粒载体pDF-D-SacB;利用抗乙肝表面抗原抗体的基因为模板,PCR扩增重链和轻链基因片段。将PCR扩增的轻链基因和重链基因分别插入载体pDF-D-SacB内,利用电转化的方法将其转入Trans1-Blue大肠杆菌,构建2个初级质粒,再利用初级质粒超感染BSl365菌,使其轻链与重链发生重组,获得重组质粒,进一步获得抗乙肝表面抗原抗体的噬菌体。之后利用该噬菌体感染大肠杆菌Trans1-Blue进行扩增,得到大量抗乙肝表面抗原的噬菌体抗体。最后,通过酶联免疫吸附剂测定检测所获得的抗体。结果通过向pDF重轻链区域插入SacB基因,改造抗体基因克隆位点,构建了pDF-D-SacB载体;经检测,pDF-D-SacB可以表达具有功能的Fab噬菌体抗体,可以在分泌Cre蛋白酶的细菌胞内发生预期的Cre-Loxp介导的定点重组。结论所获得的含自杀基因的噬菌粒载体pDF-D-SacB适用于构建大容量噬菌体抗体库。     

基于核酶自剪切机制稳定分泌丙型肝炎病毒的细胞模型

Objective To construct a stable HCV-producing cell model for anti-HCV drug research. Methods The HCV-ribozyme recombinant plasmid pJFHl-Rbz was constructed to generate the exact 5' and 3' ends of HCV genomic RNA by placing two self-cleaving ribozymes at both ends of the HCV JFH-1 cDNA. The plasmid was then transfected into HepG2 cells and the resultant clones were screened with G418. Subsequently, immunofluorescence and Western blot were performed to detect the expression of HCV core protein, HCV RNA level was quantitated by TaqMan real-time PCR method and HCV particles was detected by electron microscopy. Results HCV core protein was detected in die screened cell clone, and the level of HCV RNA was up to 1 ×107 in the culture medium. Electron microscopy showed the viral particles in the culture suspension were approximately 55 nm in diameter. IFN-treating experiment demonstrated that the HCV RNA level decreased with the increasing concentration of IFN α. Conclusions We constructed a stable HCV-producing cell model which can be used for anti-HCV drug research.     

1株高毒力型肺炎克雷伯菌临床分离株毒力及耐药性分析

目的　对1株临床分离的高毒力型肺炎克雷伯菌菌株进行毒力基因及耐药基因分析,为临床复杂肺炎克雷伯菌感染的诊断及抗生素使用提供参考。方法　首先使用PCR方法对该菌株进行血清学分型、毒力基因和耐药基因检测,然后利用二代和三代高通量测序平台对该菌株进行全基因组测序和序列拼接,应用生物信息学方法全面分析该菌株毒力基因及耐药基因。结果　该菌株血清型为K1型,采用PCR方法发现该菌株携带wabG、uge、kfuBC、aerobactin、rmpA、magA和 fimH 7个毒力基因及超广谱β-内酰胺酶耐药基因（基因型为SHV型）。高通量测序进一步发现该菌株的基因组还携带clbB、iroC和rffG 3个毒力基因。结论　该肺炎克雷伯菌临床分离株血清型为K1,除了携带喹诺酮类和β-内酰胺类耐药基因外,还含有多种毒力基因,增加了治疗难度。全面分析感染菌株携带的毒力基因和耐药基因,有针对性地选择抗生素,可提高抗感染治疗的效率,减少并发症的发生。     

新城疫病毒对Hep-2肿瘤细胞的抑制效应

目的探讨新城疫病毒(newcastlediseasevirus,NDV)对Hep-2肿瘤细胞的杀伤效应及其免疫刺激作用。方法采用考马斯亮兰染色法观察NDV感染对Hep-2肿瘤细胞细胞骨架的影响。运用甲基噻唑基四唑(methylthiazolyltetrazolium,MTT)染色法检测NDV感染致Hep-2肿瘤细胞死亡的杀伤率。通过免疫荧光结合流式细胞仪(flowcytometer,FCM)检测Hep-2肿瘤细胞表面主要组织相容性复合体Ⅰ类分子(majorhistocompabilitycomplexclassImolecules,MHC-I)的表达情况。另外,分离人外周血淋巴细胞(peripheralbloodmononuclearcells,PBMC)作为效应细胞,以NDV感染的Hep-2肿瘤细胞作为靶细胞,同时设空白细胞对照,通过特异性细胞毒T淋巴细胞实验,探讨NDV所介导的抑瘤作用。结果NDV可致Hep-2肿瘤细胞的细胞骨架发生改变,对体外培养Hep-2肿瘤细胞的杀伤率达77.7%,可上调其表面MHC-I类分子的表达,并且能够刺激增强人外周血淋巴细胞中肿瘤特异性细胞毒性T淋巴细胞(cytotoxicTlymphocyte,CTL)活性,杀伤率为23.54%。结论NDV可有效杀伤Hep-2肿瘤细胞,并刺激产生特异性抗肿瘤免疫反应。     

人白细胞介素18和新城疫病毒HN基因嵌合表达载体的构建与表达

目的：构建人白细胞介素18（IL-18）与新城疫病毒（NDV）HN基因嵌合表达质粒。 方法：选用适当的限制性核酸内切酶将NDV的HN基因连接至真核表达质粒pVAX1 IL-18中IL-18基因的尾部,同时替换掉IL-18基因的终止子,构建表达IL-18 HN 嵌合基因的pVAX1 IL-18 HN质粒,经酶切鉴定正确后,通过脂质体介导转染HeLa细胞,应用Western blotting及血凝试验检测其表达情况。 结果：酶切鉴定证实正确地构建了pVAX1 IL-18 HN嵌合表达质粒,Western blotting和血凝试验检测结果表明,嵌合后的IL-18和HN基因均能够表达,且表达的HN蛋白具有较高的血凝活性。 结论：IL-18和HN基因嵌合后不影响二者的表达,而且表达的HN蛋白具有血凝活性。     

基于核酶自剪切机制稳定分泌丙型肝炎病毒的细胞模型

Objective To construct a stable HCV-producing cell model for anti-HCV drug research. Methods The HCV-ribozyme recombinant plasmid pJFHl-Rbz was constructed to generate the exact 5' and 3' ends of HCV genomic RNA by placing two self-cleaving ribozymes at both ends of the HCV JFH-1 cDNA. The plasmid was then transfected into HepG2 cells and the resultant clones were screened with G418. Subsequently, immunofluorescence and Western blot were performed to detect the expression of HCV core protein, HCV RNA level was quantitated by TaqMan real-time PCR method and HCV particles was detected by electron microscopy. Results HCV core protein was detected in die screened cell clone, and the level of HCV RNA was up to 1 ×107 in the culture medium. Electron microscopy showed the viral particles in the culture suspension were approximately 55 nm in diameter. IFN-treating experiment demonstrated that the HCV RNA level decreased with the increasing concentration of IFN α. Conclusions We constructed a stable HCV-producing cell model which can be used for anti-HCV drug research.     

1株高毒力型肺炎克雷伯菌临床分离株毒力及耐药性分析

目的对1株临床分离的高毒力型肺炎克雷伯菌菌株进行毒力基因及耐药基因分析,为临床复杂肺炎克雷伯菌感染的诊断及抗生素使用提供参考。方法首先使用PCR方法对该菌株进行血清学分型、毒力基因和耐药基因检测,然后利用二代和三代高通量测序平台对该菌株进行全基因组测序和序列拼接,应用生物信息学方法全面分析该菌株毒力基因及耐药基因。结果该菌株血清型为K1型,采用PCR方法发现该菌株携带wabG、uge、kfuBC、aerobactin、rmpA、magA和fimH 7个毒力基因及超广谱β-内酰胺酶耐药基因(基因型为SHV型)。高通量测序进一步发现该菌株的基因组还携带clbB、iroC和rffG 3个毒力基因。结论该肺炎克雷伯菌临床分离株血清型为K1,除了携带喹诺酮类和β-内酰胺类耐药基因外,还含有多种毒力基因,增加了治疗难度。全面分析感染菌株携带的毒力基因和耐药基因,有针对性地选择抗生素,可提高抗感染治疗的效率,减少并发症的发生。     

基于核酶自剪切机制稳定分泌丙型肝炎病毒的细胞模型

目的 利用核酶自剪切机制建立稳定分泌HCV的细胞膜型.方法 以HCV感染性克隆的全基因组cDNA重组质粒为基础,在基因组两侧引入核酶序列,构建重组质粒pJFH1-核酶,并转染入HepG2细胞,加入G418溶液筛选整合有该质粒的细胞克隆.用荧光定量PCR、免疫荧光、Westrn blot、透射电镜等技术挑选稳定分泌HCV的单细胞克隆.结果 成功筛选到稳定分泌HCV的单细胞克隆,该细胞克隆能够有效产生HCV相关蛋白,上清液中HCV滴度达到1×107拷贝/ml,电子显微镜观察HCV直径为55 nm,上清液中病毒滴度随干扰素α浓度的升高而降低. 结论 利用核酶自剪切机制可建立稳定分泌HCV的细胞模型,该模型可用于抗HCV药物的筛选.