脊髓灰质炎减毒活疫苗的高效纯化及特性研究

用就Ｑ－Ｓｅｐｈａｒｏｓｅ Ｆａｓｔ Ｆｌｏｗ对Ｖｅｒｏ细胞基质制备的Ｉ型口服脊髓灰质炎减毒活疫苗悬液进行纯化。病毒液经滤过澄清和超浓缩,获得８５％的病毒感染性滴度回收率,而经Ｑ－Ｓｅｐｈａｒｏｓｅ Ｆ．Ｆ．纯化的病毒悬液,病毒感染性滴度回收率达１００％。纯化后的病毒液用α－＾３２ＰｄＡＴＰ标记ＤＮＡ探针膜杂交法测定,宿主Ｖｅｒｏ细胞基质ＤＮＡ残余含量远低于１００ｐｇ／剂量的标准;ｒｃｔ／４０特征     

人r型基因工程干扰素中残余DNA的检测

采用地高辛标记探针,以核酸杂交法检测人ｒ型基因工程干扰素（ＩＦＮ－ｒ）制品中残余ＤＮＡ含量,结果表明,自制的二组ＤＮＡ标准品相应量间显示的色斑相差悬殊,提示高蛋白含量对痕量残余ＤＮＡ的检测干扰较大,添加ＩＦＮ－ｒ的ＤＮＡ标准品比纯ＤＮＡ标准品更合理,以此测得各样品均符合ＷＨＯ要求（〈１００ｐｇ／剂量）,方法敏感性为４ｐｇ。     

地高辛标记核酸探针斑点杂交法检测轮状病毒疫苗中残余MA－104细胞DNA含量的研究

本文报导用地高辛标记核酸探针和分子斑点杂交技术检测轮状病毒基因重配株Ｌ－３株活疫苗中残余ＭＡ－１０４细胞ＤＮＡ含量的方法。提取和纯化ＭＡ－１０４细胞ＤＮＡ,将其ＡｌｕＩ酶切片段用随机引物法引导ＤＮＡ标记为探针。待检样品抽提核酸后点膜进行斑点杂交。此法灵敏度高,可检出０．１４ｐｇ的ＤＮＡ,特异性强,与非同源性ＤＮＡ无杂交。用此法检测轮状病毒基因重配株Ｌ－３株制备的疫苗,ＭＡ－１０４细胞残余ＤＮＡ含量低于１４ｐｇ低于ＷＨＯ限量标准,结果表明此重配株用于研制疫苗是安全的。     

HRP-HBVDNA探针在临检应用中的研究

本文介绍了一种简便的检测血清ＨＢＶＤＮＡ的方法。参照Ｒｅｎｚ等人的标记方法,构建了直接酶标ＨＲＰ ＨＢＶＤＮＡ探针。此探针经与固定在硝酸纤维素滤膜上的血清靶ＤＮＡ杂交后,可通过化学发光自显影检测技术观察结果。敏感度可检测０－１ｐｇ靶ＤＮＡ,相当于同位素探针的灵敏度。对６３份ＨＢｓＡｇＨＢｅＡｇ和Ａｎｔｉ ＨＢｃＥＬＩＳＡ阳性血清以及２４份ＨＢｓＡｇＡｎｔｉ ＨＢｃ阳性,ＨｂｅＡｇ阴性血清用ＨＲＰ ＨＢＶＤＮＡ探针进行检测,结果探针ＨＢＶＤＮＡ阳性率分别为１００％（６３）和５８％（１４）;对５０份ＨＢｓＡｇ,ＥＬＩＳＡ阴性和ＡＬＴ正常的血清,探针ＨＢＶＤＮＡ全部阴性。实验结果表明本方法具有很大的推广应用价值。     

四种鱼类外周血红细胞细胞周期及DNA含量

通过流式细胞仪测量了兴国红鲤（Ｃｙｐｒｉｎｕｓ ｃａｒｐｉｏ Ｖａｒ． Ｓｉｎｇｕｏｎｅｎｓｉｓ）、奥利亚罗非鱼（Ｓａｒｏｔｈｅｒｏｄｏｎ ａｕｒｅａ）、 鳙（Ａｒｉｓｔｉｃｈｔｈｙｓ ｎｏｂｉｌｉｓ Ｒ．）和团头鲂（Ｍｅｇａｌｏｂｒａｍａ ａｍｂｌｙｃｅｐｈａｌａ Ｙｉｎ．）红细胞的ＤＮＡ含量,四种鱼与鸡红细胞ＤＮＡ含量的比值分别为１·６５、０．９６、０．９１、１·１５,以鸡红细胞ＤＮＡ含量２．３ｐｇ／Ｎ计算,四种鱼二倍体体细胞的 ＤＮＡ含量分别为３．８０ ｐｇ／Ｎ, ２． ２２ｐｇ／Ｎ、２． ０８ｐｇ／Ｎ、 ２． ６６ｐｇ／Ｎ。另外,四种鱼外周血红细胞分别有２６％、 ２６％、 ２３％、 ２４％的细胞处于 ＤＮＡ合成期（Ｓ）,ＤＮＡ合成后期（Ｇ２）和分裂期（Ｍ）,这表明这四种鱼类的外周血红细胞并非失去分裂能力的特化细胞群,它们表现了较强的细胞周期现象。这有可能是这几种硬骨鱼类外周血仍具有造血功能的缘故。     

大规模区带离心纯化Vero细胞乙脑疫苗

本文报道一种适合疫苗生产的大规模纯化Ｖｅｒｏ细胞乙脑疫苗的方法。原疫苗经适当浓缩和去除ＤＮＡ处理后,用不连续蔗糖梯度（３６％和６０％）。３２６００ｇ,速率区带离心４ｈ。纯化后疫苗的效力比中国参考疫苗高出６倍以上,补体结合抗原比中国参考疫苗高４～８倍。总蛋白含量低于３０μｇ／ｍＬ,牛血清含量降至０．５μｇ／ｍＬ以下,细胞残余ＤＮＡ低于１００ｐｇ／０．５ｍＬ。用此法连续制备三批纯化疫苗,其纯度和效力均高于日本鼠脑纯化疫苗。此法对于制备其它纯化Ｖｅｒｏ细胞疫苗也具有一定的参考意义。     

用地高辛标记探针检测基因工程人β干扰素制品中的外源DNA

基因工程人β干扰素工程菌经发酵培养、纯化后获得纯的制品,采用斑点杂交技术,用非放射性地高辛标记超声裂解的全工程菌ＤＮＡ作为探针,检测基因工程人β干扰素纯品,结果显示：基因工程人β干扰素纯品中的外源ＤＮＡ含量小于１００ｐｇ／剂。     

用套式多聚酶链反应技术监测乙型肝炎病毒的母婴垂直传播

用套式多聚酶链反应（Ｎｅｓｔｅｄ－ＰＣＲ）技术对１６９对ＨＢｓＡｇ及ＨＢｓＡｇ／ＨＢｅＡｇ阳性孕妇及其新生儿外周血清进行了ＨＢＶ－ＤＮＡ检测。１０３对ＨＢｓＡｇ阳性孕妇及其新生儿外周血清中ＨＢＶ－ＤＮＡ阳性率分别为７２．８％和３３．０％;６６对ＨＢｓＡｇ和ＨＢｅＡｇ双阳性的孕妇及其新生儿外周血清中ＨＢＶ－ＤＮＡ阳性率分别为８６．４％和４３．９％。对５５例ＨＢｓＡｇ及ＨＢｓＡｇ／ＨＢｅＡｇ阳性产妇产后的初乳进行了ＨＢＶ－ＤＮＡ检测,结果ＨＢＶ－ＤＮＡ阳性率为３６．４％。结果表明ＨＢｓＡｇ和ＨＢｅＡｇ双阳性的孕妇及其新生儿外周血清ＨＢＶ－ＤＮＡ检出率较ＨＢｓＡｇ单阳性的孕妇及其新生儿要高,其初乳中ＨＢＶ－ＤＮＡ的检出率也高。还对１０５例注射了乙肝疫苗及高价乙肝特异性免疫球蛋白的６月龄婴儿的外周血清进行了ＨＢＶ－ＤＮＡ检测,结果有２３例阳性。     

用套多聚酶链反应技术监测乙型肝炎病毒的母婴垂直传播

用套式多聚酶链反应（Ｎｅｓｔｅｄ－ＰＣＲ）技术对１６９对ＨＢｓＡｇ及ＨＢｓＡｇ／ＨＢｅＡｇ阳性孕妇及其新生儿外周血清进行了ＨＢＶ－ＤＮＡ检测,１０３对ＨＢｓＡｇ阳性孕妇及其新生儿外周务中ＨＢＶ－ＤＮＡ阳性率分别为７２．８％和３３．０％;６６对ＨＢｓＡｇ和ＨＢｅＡｇ双阳性的孕妇及其新生儿外周血清中ＨＢＶ－ＤＮＡ阳性率分别为８６．４％和４３．９％,对５５例ＨＢｓＡｇ及ＨＢｓＡｇ／ＨＢｅＡｇ阳性产妇产后     

NRP—HBVDNA探针在临检应用中的研究

本文介绍了一种简便的检测血清ＨＢＶＤＮＡ的方法。参照Ｒｅｎｚ等人的标记方法，构建了直接酶标ＨＲＰ－ＨＢＶＤＮＡ探针。此探针经与固定在硝酸纤维素滤膜上的血清靶ＤＮＡ杂交后，可通过化学发光自显影检测技术观察结果。敏感度可检测０．１ｐｇ靶ＤＮＡ，相当于同位素探针的灵敏度。对６３份ＨＢｓＡｇ ＨＢｅＡｇ和ＡｎｉｔＨＢｃ ＥＬＩＳＡ阳性血清以及２４份ＨＢｓＡｇ Ａｎｔｉ－ＨＢｃ阳性，ＮｂｅＡｇ阴性血清用ＨＲ     

人重组白细胞介素12在CHO细胞中的表达

将人白细胞介素12（interleukin 12, IL-12）两条链p35及p40全长cDNA分别亚克隆至真核表达载体pcDNA3中,构建了pcDNA3/p35a,pcDNA3/p40a,pcDNA3/p35b,pcDNA3/p40b四种真核细胞重组表达质粒,利用磷酸钙共沉淀法转染中国苍鼠卵巢(CHO)细胞. 通过对阳性克隆的筛选鉴定,获得了稳定表达人IL-12的CHO细胞株,活性最高的一株表达量为105 U/ml.此细胞株经半年的传代培养,能够稳定地分泌IL-12.结果显示：IL-12在CHO细胞中的稳定表达受到重组质粒结构、DNA整合、mRNA转录、蛋白质翻译等多因素的影响,IL-12两个亚基在CHO细胞中的共同表达是产生有生物活性IL-12的基础.     

定点整合人Bcl-2基因的CHO/dhfr-细胞株的建立

构建重组载体质粒pMCEfrt—Bcl-2,利用FIp—In^TM定点重组系统,在CHO—dhfr^-细胞内定点整合人Bcl-2基因,通过Western印迹检测重组细胞Bcl-2蛋白的表达。通过流式细胞仪和DNA Ladder检测在高NH4C1条件下细胞的凋亡情况;用台盼蓝染色检测在无血清IMDM培养基中细胞的活细胞数目和活细胞比例。结果获得了稳定表达Bcl-2基因的细胞株CHO—Bcl-2,该细胞株能高水平表达Bcl-2蛋白。在无血清培养过程中,CHO—Bcl-2细胞比对照细胞保持高约15％的活细胞比例,细胞总数高25％。CHO-Bcl-2在高NH4^＋（50mmol／L）培养条件下具有较低的凋亡水平。建立了能够高表达Bcl-2基因并具有一定的抗凋亡能力的重组CHO／dhfr^-细胞株。     

小鼠pEGFP-Hoxa11真核表达载体的构建及表达

目的 构建和鉴定Hoxa11和EGFP双基因共表达真核载体.方法 采用DNA重组技术,将目的 基因Hoxa11克隆至含有报告基因EGFP的pEGFP-N1真核表达载体中,构建的真核表达载体pEGFP-Hoxa11经PCR,双酶切及基因测序鉴定;转染至CHO细胞,荧光显微镜下观察重组质粒的表达,提取细胞蛋白Western印迹检测蛋白表达.结果 pEGFP-Hoxa11重组质粒构建成功.构建的真核表达载体pEGFP-Hoxa11能在CHO细胞中有效表达.结论 成功构建了共表达Hoxa11和EGFP的真核表达载体,并能在CHO细胞中有效表达.为进一步研究Hoxa11的功能提供实验基础.     

A compendium of stable hotspots in the CHO genome

The use of targeted integration for industrial CHO cell line development currently requires significant upfront effort to identify genomic loci capable of supporting multigram per liter therapeutic protein production from a limited number of transgene copies. To address this barrier to widespread adoption, we characterized transgene expression from thousands of stable hotspots in the CHO genome using the Thousands of Reporters Integrated in Parallel high-throughput screening method. This genome-scale data set was used to define a limited set of epigenetic properties of hotspot regions with sizes on the order of 10 kb. Cell lines with landing pad integrations at eight retargeted hotspot candidates consistently exhibited higher transgene mRNA expression than a commercially viable hotspot in equivalent culture conditions. Initial benchmarking of NISTmAb and trastuzumab productivity from one of these hotspots yielded mAb productivities of approximately 0.7–2 g/L (qP range: 2.9–8.2 pg/cell/day) in small-scale fed-batches. These findings indicate the list of hotspot candidates identified here will be a valuable resource for targeted integration platform development within the CHO community.     

Comparative mutagenic efficiencies of the DNA adducts from the cooked-food-related mutagens Trp-P-2 and IQ in CHO cells

The relationship between DNA-adduct formation and mutagenicity of two heterocyclic aromatic amines associated with cooked foods was determined in a CHO cell strain lacking nucleotide excision repair. Cells were exposed to tritiated IQ (2-amino-3-methylimidazo[4,5-f]quinoline) or Trp-P-2 (3-amino-1-methyl-5H-pyrido[4,3-b]indole) supplemented with hamster S9 microsomal fraction for metabolic activation. DNA from nuclei was isolated by DNAase-mediated elution from polycarbonate filters after RNAase and proteinase treatment. The presumed metabolites of both compounds bound to DNA in a dose-dependent fashion. Although the dose required to produce 50% cell killing was 15 times higher for IQ than Trp-P-2, the amount of radioactive material bound to DNA at that dose was about 10-fold lower with IQ. When mutations at the hprt and aprt loci were compared with the estimated levels of adducts, the calculated mutagenic efficiency of the adducts was about 4 mutations per 1000 adducts for both compounds, assuming a target sequence of 1000 base pairs for either locus. We conclude that IQ is acting as a weak mutagen in this system because its extracellular metabolites either do not reach or do not react efficiently with the DNA of the CHO cells.     

Cell cycle-dependent DHFR and t-PA production in cotransfected, MTX-amplified CHO cells revealed by dual-laser flow cytometry

The cell cycle-dependent regulation of the cellular dihydrofolate reductase content (DHFR) and tissue plasminogen activator (t-PA) production and secretion in plasmid-amplified cells was investigated in the DHFR-negative CHO cells transfected with the plasmid pSV-tPA.dhfr. This plasmid, carrying the dhfr and t-PA gene under control of different promotors, was amplified by serial passages in 5 microM methotrexate (MTX) for dhfr gene amplification. The intracellular amount of DHFR was quantitated in viable cells by MTX-FITC labeling and flow cytometric analysis of the FITC fluorescence. In comparison with the original CHO cells, the pSVtPA.dhfr-amplified cells showed a greater than 230-fold increase in MTX-FITC fluorescence. Using dual laser flow cytometry (uv: vital cell cycle with Hoechst 33342; 488 nm: DHFR with MTX-FITC), we show a maximum increase in the intracellular DHFR content during G1 and/or at G1/S transition (100 to 157%), followed by a continuous increase to 200% during S and G2/M. To determine t-PA production CHO cells were sorted from G1-, early/late S-, and G2/M-phase. After 1-, 2-, and 4-h incubation periods, t-PA production was quantitated using a sensitive t-PA ELISA technique. We found that t-PA production and secretion (2-h assay), unlike the expression of DHFR, increased continuously from relatively 100% in G1 to 127% in early S and reached its maximum of 159% in late S, whereas in G2/M-phase it decreased to 118%. Our results show that in pSVtPA.dhfr-coamplified CHO cells gene products DHFR and t-PA both exhibit different cell cycle-correlated accumulation and secretion, respectively, indicating that the brightest MTX-FITC-positive cells (G2/M) do not display the highest t-PA secretion rate.     

CHO细胞株开发技术策略探讨

主要介绍了单克隆抗体药物工业生产中宿主细胞选择、表达载体构建、转染方法、筛选技术、细胞培养工艺技术方法以及最后选定细胞株的标准等,结合单抗药物CHO细胞株开发和培养工艺的经验,对当前我国单抗CHO细胞株开发技术策略进行了探讨。     

绿色荧光蛋白标记的葡萄糖转运蛋白4稳定表达细胞系的建立

目的:建立稳定表达EGFP标记的葡萄糖转运蛋白4的CHO细胞系,为研究GLUT4在CHO细胞中的转运调节机制奠定基础。方法:采用分子克隆方法构建GLUT4-EGFP的融合蛋白,在FLP-in的CHO细胞系中表达,潮霉素筛选后得到稳定的细胞系。结果:通过共聚焦显微镜的检测,证明了此稳定细胞系的阳性率达到了99%。定位研究表明大部分GLUT4以囊泡形式分布在CHO细胞胞浆内,但是质膜上也有少量的GLUT4。结论:建立了一个稳定表达GLUT4-EGFP的CHO细胞系,为进一步研究GLUT4的转运提供了一个很好的细胞模型。