Combined immunity of DNA vector and recombinant vaccinia virus expressing Gag proteins of equine infectious anemia virus

In order to develop a new vaccine candidate for equine infectious anemia virus (EIAV), gag gene of Chinese donkey leukocyte attenuated strain (EIAV DLV) and its parental virulent strain (EIAV LN) were inserted respectively into the TK region of the Tiantan strain (VV) of vaccinia virus by homologous recombination and the positive clone was confirmed by blue plaque assay. Protein expression was examined by Western blot. Prime and prime-boost procedures were used to immunize mice with two DNA vectors and two recombinant vaccinia viruses expressing EIAV Gag proteins. The results showed that the specific lysis of CTL responses in the DNA rVV groups was stronger than those in the DNA groups, amounting to 31%. Although the levels of specific antibodies were not significantly different, we could conclude that the recombinant vaccinia virus could boost the cellular responses following DNA vector priming. There was no detectable difference between the immune responses induced by DLV and LN Gag proteins. This data demonstrates that the combined immunity of DNA vector and recombinant vaccinia virus expressing EIAV gag proteins, utilizing the prime-boost procedure, can drive immunized mice to produce powerful cellular responses. These results lay an important foundation for the development of a new EIAV genetic engineering vaccine.     

正交实验优化RGD-蛛丝蛋白基因工程菌高密度发酵条件

通过正交实验对RGD-蛛丝蛋白基因工程菌高密度发酵条件进行优化.选择pH、温度、诱导剂、前体物甘氨酸/丙氨酸4因素,分别在3个水平上进行考察.当菌体密度OD600 nm为35左右时,添加IPTG诱导5 h,确定了发酵诱导条件为前体物甘氨酸/丙氨酸质量浓度为0.5%,诱导剂IPTG浓度为0.4 mmol/L,pH为7.0,温度为37℃.工程菌密度OD600 nm 可达到53.1,目的蛋白比例可达到24.3%,每L发酵液菌体经纯化可得到410 mg的目的蛋白.     

病毒载体疫苗研究进展

从非复制性病毒（家禽痘、野鸟痘、痘苗和人类腺病毒）载体重组活疫苗、腺病毒载体重组口服活疫苗和杆状病毒载体重组亚单位疫苗三方面，评述了以病毒为表达载体的基因工程疫苗近年研究取得的重大进展。     

蓝细菌新质粒载体pPRS－1的构建

以蓝细菌Ｐｌｅｃｔｃｎｅｍａｂｏｒｙａｎｕｍ内源小质粒ｐＰｂｓ（１．５ｋｂ）和Ｅ。ｃｏｌｉ质粒载体ｐＢＲ３２２（４．３ｋｂ）为材料，用限制性内切核酸酶ＣｌａⅠ分别消化，经Ｔ＿４ＤＮＡ连接酶连接，转化Ｅ．ｃｏｌｉＨＢ１０１感受态细胞，在含Ａｍｐ（Ａｐ）和含Ｔｅｔ（Ｔｃ）的ＬＢ琼脂培养基上筛选出Ａｍｐ￣ｒＴｅｔ￣ｓ的转化子，提取转化子的质粒，用ＣｌａⅠ消化，得１．５ｋｂ和４．３ｋｂ两片段，表明转化子所含质粒是ｐＰｂｓ和ｐＢＲ３２２的重组质粒，定名为ｐＰＲＳ－１。     

Ralstonia eutropha CH34 酯酶基因在大肠杆菌中的表达及酶学特性

从RalstoniaeutrophaCH34基因文库中筛选出编码酯酶EstA的基因 ,将其克隆于大肠杆菌可以得到稳定表达 ,表达产物具有较高的酯酶活性。对重组酯酶的各种酶学性质进行的研究表明 ,酯酶EstA的最适反应 pH为 7.0 ,其最适反应温度为 5 0～ 80℃ ,该酶对酸碱环境适应性较强。在 pH4～ 10 .5范围内保持稳定 ,而在 0～ 6 0℃范围内保温 2h ,该酶仍能保持 80 %以上的活力。     

长期应用重组人睫状神经因子(rhCNTF)对谷氨酸钠肥胖大鼠血脂的影响

目的研究长期应用rhCNTF对谷氨酸钠(MSG)肥胖大鼠血脂的影响。方法建立MSG肥胖大鼠模型。3月龄时将肥胖动物随机分5组:分别皮下注射rhCNTF300μg·kg-1·d-1(高剂量组)、100μg·kg-1·d-1(中剂量组)、30μg·kg-1·d-1(低剂量组);西布曲明灌胃8 mg·kg-1·d-1(阳性对照组);模型组和对照组均给予生理盐水1 mL·kg-1·d-1,连续给药33 d。末次给药后24 h,同时动物禁食过夜后,在水合氯醛麻醉下测体重、身长,计算LI;断头后取腹部脂肪称重计算脂肪系数;腹主动脉取血离心后测血清总胆固醇、甘油三酯、高密度脂蛋白、血糖和血清胰岛素水平。结果(1)造模:正常大鼠189.40±38.72 g,谷氨酸钠肥胖大鼠平均体重(246.72±36.67)g,(P<0.001);LI(Lee’s指数)分别为289.27±9.05和304.42±9.64(P<0.001),说明造模成功。(2)药物实验结果高、中剂量给药组LI、脂肪系数、血总胆固醇、甘油三酯、血糖明显下降,高剂量组胰岛素水平也有所下降,达到统计学要求的显著性。结论rhCNTF30～300μg·kg-1·d-1皮下注射连续用药33 d,对谷氨酸钠肥胖大鼠具有明显的降脂作用,可能对Ⅱ型糖尿病肥胖有效。     

腺病毒介导的bFGF基因对大鼠大脑中动脉闭塞模型的作用

采用改良的Zea Longa法制备大鼠脑缺血模型,研究腺病毒介导的bFGF的基因治疗对大鼠大脑中动脉闭塞(MCAO) 模型的治疗作用及脑血管发生的影响,将30只SD大鼠随机分为假手术组、空载体组（Ad-null组）和治疗组（Ad-bFGF组）,于造模成功后24h尾静脉给药.检测实验各组脑组织含水率的变化,通过核磁共振的和免疫组化分别检测实验各组大脑梗死体积和血管发生的变化.结果发现治疗组大鼠脑组织含水率和脑梗死面积明显小于空载体组,脑血管密度显著高于空载组.说明腺病毒介导的bFGF基因卡显著减小脑组织含水率和脑梗死面积,促进脑部血管发生,为缺血性脑卒中的基因治疗提供了新的途径.     

硅藻DNA片段在表达质粒pMZR中再克隆的研究

用部分酶切法切开表达质粒 pMZR 中一个 HindⅢ位点后,插入了一个带 HindⅢ粘性末端的1kb 硅藻 DNA 片段重组 DNA 分子转化 E.coli LE392,对转化子中的重组 DNA 分子用酶切分析后,鉴定了1kb DNA 片段插入 pMZR 的位置。     

rHEPO对大鼠急性视网膜光损伤的保护作用及时效性研究

目的探讨重组人促红细胞生成素(r HEPO)对大鼠急性视网膜光损伤的保护作用及时效性.方法选取4周龄雄性SD大鼠48只,随机分成5组:正常对照组、模型对照组、模型治疗1、2、3组,其中正常对照组8只,其余各组均为10只,应用手术显微镜(光照强度为(22 000±1 000)lux)对模型各组造模.模型治疗1、2、3组:分别在光照前4 h、光照后立即、光照后3 d按照5 000 IU/kg腹腔注射r HEPO 1次.模型对照组:光照前后均未给予药物干预.7 d后处死所有大鼠,摘取眼球,应用苏木精-伊红(HE)染色观察视网膜的变化;应用免疫组织化学的方法检测Caspase-3的表达.结果 1)HE染色:正常对照组中大鼠视网膜各层结构完整,层次分明,排列整齐,细胞核形态规整,染色均匀.模型对照组中大鼠视网膜光感受器内、外节排列紊乱,有空泡形成,部分断裂;外核层较正常对照组明显变薄(P0.05),核间隙加大,部分有碎核现象.模型治疗各组大鼠视网膜光感受器内、外节排列紊乱,有小空泡形成;外核层较正常对照组有不同程度变薄(P0.05),模型治疗1、2组好于模型对照组(P0.05),且1组优于2组(P0.05),模型治疗3组与模型对照组比较差异无统计学意义.2)Caspase-3表达:与正常对照组相比,模型各组的Caspase-3表达均有所增强(P0.05);模型治疗1、2、3组表达依次增强,两两比较差异具有统计学意义;模型对照组与模型治疗3组表达最强,二者之间无差异(P0.05).结论 r HEPO对视网膜光损伤具有保护作用,并具有一定的时效性,早期用药效果好,其中光损伤前4 h预用药优于光损伤后立即用药.     

Chitotriosidase and gene therapy for fungal infections

Chitotriosidase secreted by activated human macrophages has been implicated in the defence against chitin-bearing pathogens. The antifungal properties of human chitotriosidase were investigated here following retroviral vector-mediated gene transfer of the open reading frame of the chitotriosidase gene into Chinese hamster ovary cells. A chitinase assay confirmed that the engineered cells secreted recombinant chitotriosidase constitutively. Two dimensional gel electrophoresis and western blotting indicated that the recombinant protein is the major, chitin-binding, fifty kilodalton isoform. Culture medium conditioned by the transduced cells inhibited growth of isolates of Aspergillus niger, Candida albicans and Cryptococcus neoformans. Furthermore, longevity was significantly increased in a mouse model of cryptococcosis when cells transduced with the chitotriosidase gene and encapsulated in alginate microspheres were implanted subcutaneously in the animals. Engraftment of microcapsules containing cells transduced with the chitotriosidase gene has the potential to combat infections caused by chitinous pathogens through the prolonged delivery of recombinant chitotriosidase. Received 29 November 2008; received after revision 11 January 2009; accepted 13 January 2009