CHO—C28细胞收集液中乙型肝炎病毒表面抗原收率的研究

用CHO-C28细胞表达乙型肝炎病毒表面抗原(HBsAg)生产基因工程乙肝疫苗,其产量受到CHO-C28细胞表达外源基因量的影响.本文通过CHO-C28细胞连续培养过程中表达(HBsAg)的参数、纯化过程中硫酸铵(A·S)饱和度、细胞收集液放置时间三个因素对RPHA滴度影响的研究结果表明细胞收集液以45%饱和度的A·S沉淀HBsAg能获得较高的HBsAg收率,细胞收集液4℃放置时间不宜超过15 d,RPHA滴度在132～1128之间的细胞收集液均可进入纯化流程进行纯化.     

B16及其克隆亚系细胞分泌乙型肝炎表面抗原的稳定性、动态和最佳条件

B16及其亚系细胞B16-7和B16-12在氨甲喋呤压力下连续传代7个月,以B16-7和B16-12分泌乙型肝炎表面抗原(HBsAg)最为稳定。停用氨甲喋呤,B16分泌HBsAg的量逐步下降。用单层细胞培养法对B16-7在不同条件下分泌HBsAg的动态研究证明:细胞常规传代长成单层后换液,血清量降至2％,孵育温度降至32℃,每48小时收获换液一次,连续收获4～5次,按Abbott试剂盒的曲线估计HBsAg的累积量可高达2.5mg/升左右,即1.3×10~(12)g/细胞/24小时。     

在CHO-C28细胞大规模培养中提高收获次数及HBsAg的表达

目的：在CHO—C28细胞大规模培养过程中增加收获次数,延长细胞收获周期,提高HBeAg收获量。方法：采用15L转瓶培养CHO—C28细胞,分3组,对比观察不同小牛血清含量及pH值对细胞生长及HBeAg表达的影响,优化最佳培养条件。结果:三组比较,实验1组的收获次数最多,达25次以上,HBsAg的表达量最高,收液量最多：结论：优化了CHO—C28细胞的培养条件.     

HBsAb标记胶体金探针对HBV阳性血清感染HPT-8细胞的示踪研究

目的:为临床诊断提供HBV进入HPT-8的依据。方法:HBV阳性血清(1.5×10~8拷贝/毫升)体外感染HPT-8细胞48h,设感染组、阴性对照组和空白对照组,ELISA检测细胞培养上清中HBsAg、HBeAg,提取感染后传代的各代细胞中DNA用于PCR检测HBV DNA。免疫荧光定量PCR检测细胞培养上清中HBV DNA的滴度。采用乙肝表面抗原单克隆抗体标记的胶体金探针对感染的HPT-8细胞中的乙肝表面抗原进行标记示踪。结果:ELISA检测感染组细胞第1、2代培养上清中HBsAg阳性,PCR检测感染组第1、2代细胞HBV DNA,结果均阳性。免疫荧光定量PCR检测感染组细胞上清在第1、2代、3代48h的HBV滴度分别为8×10~4、4.6×10~3、<10~3(拷贝/毫升)。通过胶体金探针的标记:乙肝表面抗原存在于感染细胞的溶酶体内、细胞膜和绒毛上。结论:血清中的HBV病毒能进入胎盘滋养细胞,并可从感染滋养细胞的树脂切片中获得乙肝表面抗原的超微结构定位。     

共表达siRNA和hIL-12的新型乙肝多表位DNA疫苗的研究

目的 构建含有靶向乙肝表面抗原(HBsAg)基因的siRNA、乙肝复合多表位抗原基因和hIL-12共质粒表达的新型DNA疫苗,并在HepG2细胞中检测siRNA的效果以及各基因的表达。方法 设计并合成复合多表位HBV抗原基因,将其与增强型绿色荧光蛋白（EGFP）基因融合克隆进真核表达载体pVAX1的多克隆位点中,同时将带CMV启动子的完整hIL-12表达单元克隆进载体的BspH I位点之间,再设计并合成乙肝siRNA表达单元,将其克隆进载体的Mlu I位点之间,得到真核三元共表达重组质粒pVAX1-siHB-HB-EGFP-hIL12。以该重组质粒瞬时转染人肝癌细胞系HepG2,通过EGFP的荧光标记观察多表位抗原的表达,以ELISA测定培养细胞上清中hIL-12的表达,以rtPCR检测siRNA对HBsAg基因的沉默效果。结果 经酶切鉴定和测序证实共表达siRNA、hIL-12的HBV 多表位DNA疫苗构建成功。转染细胞中检测到绿色荧光,证实抗原表达;转染后48 h hIL-12的检出量为1 289 pg/mL细胞上清,72 h检出量为1 712 pg/mL细胞上清;转染后HBsAg表达量明显降低,证实siRNA效果良好。结论 成功构建乙肝复合多表位抗原基因与siRNA、hIL-12共质粒表达的DNA疫苗,并能在真核细胞中有效表达抗原与hIL-12基因,而且siRNA对HBsAg显示出明显的沉默效果。我们的工作为进一步研究该复合型DNA疫苗抗HBV的治疗效果打下基础。     

生物反应器规模化培养重组CHO-C28细胞表达HBsAg的研究

应用新型聚酯纤维盘片,采用连续灌注培养方式,分别试验了细胞接种量、pH、DO、罐流速度等因素对CHO-C28细胞生长分泌HBsAg的影响,初步建立了5L生物反应器生产重组乙型肝炎疫苗的生产工艺。经3次试验培养,每次培养60d,较适宜的培养条件确定为:pH6.80-7.10,DO 20%-30%,温度36-37℃,灌流速度138ml/h,接种浓度1.9×106cell/ml。收获液的HBsAg平均滴度是1∶256,最高滴度可达1∶512,纯化后的HBsAg产率为0.912mg/L。最后对反应器培养工艺与现行的转瓶培养工艺进行了比较,生物反应器培养具有可控制培养条件、不易污染和可使HBsAg产率提高等优点。     

乙型肝炎病毒表面抗原基因在中国地鼠卵巢细胞中的高效表达及纯化抗原免疫原性的研究

本文报告了两个拷贝的adr亚型HBs基因的pSV2质粒组建,其中一个拷贝只含S基因,受SV40早期启动子的直接控制,另一个拷贝连接于pSV2质粒dhfr基因下游,含有前S和S基因及其本身的启动子,用此重组质粒转化CHO-dhfr~-细胞,经选择,获得了高效表达HBsAg的CHO-32-C23及CHO-Ⅱ-5细胞系,最佳培养条件及HBsAg分泌动态的研究结果表明,CHO-Ⅱ-5系细胞分泌HBsAg的最佳条件是37℃培养,培养基中加2％小牛血清,每日收换液;用5％小牛血清,每48小时收换液则次之,但较实用,转瓶培养产量约2.μg/ml,将CHO-32-C23细胞系产生的液体初步纯化,在聚丙烯酰胺凝胶上显示23k和27k蛋白带,用其免疫NIH小鼠,EDSO为0.119μg,对照血源菌ED_(50)为0.083μg,二者的免疫原性近似。     

中华仓鼠卵巢(CHO)工程细胞无血清培养的研究

以DMEM：F12(1：1)为基础培养基,通过观察细胞生长状态和检测乙肝表面抗原的表达量作为评价指标,筛选适合于CHO工程细胞生长的生长因子,如：胰岛素、转铁蛋白、氢化可的松、硒酸钠,丁二胺等。并且建立了J5SFM培养基。该培养基与商品化的无血清培养基比较,能够使细胞生长维持较长的时间,表达产物分泌量也相对较高。     

产HBsAg CHO细胞无血清培养研究

在分析CHO C2 8细胞对培养基中氨基酸利用的基础上 ,对DMEM培养基进行初步优化。再采用统计学正交分析方法 ,在初步优化的DMEM培养基中添加胰岛素、转铁蛋白等促细胞生长因子 ,建立了一种适于CHO C2 8细胞持续用无血清培养基———CHO C2 8 SFM。经转瓶维持实验 ,在CHO C2 8 SFM中维持培养的细胞 ,其乙型肝炎表面抗原 (HBsAg)表达水平达到用含 5 %FBS培养液维持的 70 %～ 80 % ,但纯化收率提高 1 0 %以上 ,可用于大规模生产。     

靶向HBs基因的shRNA表达载体的构建及其抑制HepG2.2.15表达HBVsAg的作用

探索用PGenesil-1(Pg)构建的靶向乙型肝炎病毒表面抗原(HBsAg)基因的shRNA表达载体PGenesil-1-HBs(简称Pgs),对体外培养HepG2.2.15细胞中的HBV基因及其抗原表达的抑制作用.设计、合成靶向HBV S区的3对DNA序列,分别插入PGenesil-1中构建3个siRNA表达载体Pgs1、Pgs2、Pgs3,经限制性内切酶,DNA序列测定等技术鉴定确认.筛选并确定最佳细胞接种量及重组质粒转染量后,分别或按不同组合转染HepG-2.2.15细胞,48 h后采用半定量RT-PCR检测HBVsmRNA转录水平,免疫细胞化学技术检测HBsAg表达水平,MEIA分别检测细胞裂解液和培养上清中HBsAg和HBeAg的表达水平.结果表明,HBV真核表达载体Pgs1、Pgs2、Pgs3均能不同程度地抑制HepG2.2.15细胞中的HBsAg、HBeAg合成和HBs-mRNA转录.成功构建的HBV真核表达载体Pgs1、Pgs2、Pgs3,其中PgS3能显著抑制HBsAg表达(P＜0.01).多种表达载体联合对抗原表达的抑制作用效率不同.     

青海湖裸鲤体外肝胰细胞原代与传代培养

采用组织块移植培养技术,分别用DMEM和RPM11640培养基对青海湖裸鲤肝胰组织细胞进行原代培养。培养48h组织块周围有细胞迁出,并形成生长晕。培养一周可形成单层细胞。对原代培养的单层细胞用胰蛋白酶-EDTA消化后,传代培养至第四代。确立青海湖裸鲤肝胰细胞培养条件为：培养基为DMEM,培养温度为27℃,pH值为7．0—7．5,原代培养血清浓度为20％,传代培养的血清浓度为10％,无需通入CO2和添加细胞生长因子。     

重组CHO-C_(28)细胞染色体鉴定方法的研究

分别采用五种不同条件鉴定重组CHO-C28细胞染色体。对其影响因素如用秋水仙素处理时间的长短、固定液的使用方法等进行了试验,选择出了细胞分散好、染色体形态正常、边缘清晰、便于鉴定的两种最佳条件。此方法操作简单、成功率高,适于CHO-C28细胞染色体鉴定。     

A Cell Line (HEW) from Embryos of Haddock (Melanogrammus aeglefinius) and Its Capacity to Tolerate Environmental Extremes

Cell lines can be useful experimental tools for studying marine fish, which are often difficult to routinely obtain and maintain in the laboratory. As few cell lines are available from coldwater marine fish, cultures were initiated from late gastrula embryos of haddock (Melanogrammus aeglefinus) in Leibovitz's L-15 with fetal bovine serum (FBS). From one culture, a cell line (HEW) emerged that has been grown for close to 100 population doublings, was heteroploid, and expressed telomerase activity, all of which suggest HEW is immortal. Growth occurred only if FBS was present and was optimal at 12 to 18°C. Usually most cells had an epithelial-like morphology, but under some conditions, cells drew up into round central bodies from which radiated cytoplasmic extensions with multiple branches. These neural-like cells appeared within a few hours of cultures being placed at 28°C or being switch to a simple salt solution (SSS). At 28°C, cells died within 24 h. In SSS, HEW cells survived as a monolayer for at least 7 days. The sensitivity of HEW cells to morphological change and their capacity to withstand starvation should make them useful for investigating cellular responses to environmental stresses.     

Serum-free solutions for cryopreservation of cells

With the development of cell-based assays and therapies, the purity of reagents used to grow and maintain cells has become much more important. In particular, the use of fetal calf serum for culturing cells presents a direct path for potential contamination of cell cultures. In recent years, much research has focused on the development of serum-free culturing systems, not only to alleviate difficulties due to availability and cost of fetal calf serum but also to prevent the transmission of potentially fatal diseases to human patients. Additionally, methods need to be developed for long-term storage of cell stocks that also reduce the risk of exposure to harmful diseases. As most methods employ fetal calf serum in their freezing formulations, solutions that avoid the use of fetal calf serum while providing equivalent or better recovery of cells upon thawing would be ideal. In this study, two vascular cell lines have been cryopreserved as adherent cell populations in two widely used cryoprotectants, dimethyl sulfoxide and 1,2-propanediol, and two vehicle solutions, Euro-Collins and Unisol-cryoprotectant vehicle specifically formulated for the maintenance of cell homeostasis at temperatures below 37° C. The addition of serum to these formulations was also evaluated to determine if its presence provided any additional benefit to the cells during cryopreservation. The results demonstrated that using vehicle solutions designed for lower temperatures produced viable cells that retained cell population viability values up to 75% of unfrozen controls. These results also demonstrated that including serum in the formulation provided no additional benefit to the cells and in some cases actually produced lower cell viability after cryopreservation. In conclusion, the development of solutions designed for low-temperature storage of cells provides a viable alternative to more conventional cryopreservation protocols and eliminates the necessity of including serum in these formulations.     

牛肾细胞传代稳定性研究

为了掌握牛肾细胞在体外连续传代过程中的增殖特点,将原代牛肾细胞培养形成良好单层后,按4×104个细胞/cm2连续进行传代,测定毎代次收获的细胞数,并记录每代细胞培养时形成良好单层的时间。结果显示,原代牛肾细胞传代至24代时,培养96h仍能形成良好单层,且细胞形态基本保持一致,遗传物质稳定,为建立牛肾细胞库奠定了基础。     

小鼠肌母细胞的增殖与分化

通过对小鼠肌母细胞C2C12的培养,研究C2C12细胞的增殖与分化的关系以及胰岛素在细胞分化过程中的作用。在对照组中,C2C12细胞增殖占了明显的优势,细胞形态几乎没有发生变化;而在实验组中,C2C12细胞在换为分化培养基24小时后,就出现了部分细胞衰亡和死亡的现象,尤其是在48小时细胞的死亡率达到最高,存活细胞开始从增殖期进入分化期,72小时出现了少量肌管,在96小时细胞分化效果达到最好。而在添加了胰岛素的分化培养基中的细胞分化效果明显好于没有添加胰岛素的分化培养基中的细胞,结果表明,胰岛素促进C2C12细胞的分化。     

Optimization of the differentiation of human preadipocytes in vitro

This study aimed at developing an optimal protocol for proliferation and differentiation of preadipocytes that is a prerequisite for constructing an ideal biohybrid composed of viable adipose precursor cells in a three-dimensional matrix. Such an implant could represent an adequate solution for correcting soft tissue defects, e.g., extensive deep burns or tumor resections. Preadipocytes were isolated from human subcutaneous adipose tissue samples and cultured in Dulbecco's modified eagle medium (DMEM)/Ham's F12 medium (F12) or OPTIMEM medium with or without the addition of human serum (hS) or fetal calf serum (FCS). The advantages of fibronectin-coated culture dishes for preadipocyte yield after isolation and differentiation were evaluated. After culture expansion, differentiation was induced by insulin, isobutylmethylxanthine, pioglitazone, dexamethasone, and transferrin in the absence of serum. The extent of differentiation was assayed by measuring the activity of glycerophosphate dehydrogenase as well as counting of differentiated versus undifferentiated cells. Our results show that fibronectin coating does not only strongly increase the yield of preadipocytes after isolation from adipose tissue but also significantly enhances differentiation of precursor cells to mature adipocytes. For optimal cell expansion, DMEM/F12 is more promoting than OPTIMEM and culturing with FCS shows a slightly better proliferation compared with hS supplementation. Differentiation, in contrast, is significantly improved when hS is used instead of FCS during proliferation. Our results smooth the way for autologous preadipocyte culturing and show that hS for preadipocyte culturing opens new and promising perspectives for adipose tissue engineering by optimizing in vitro expansion in cell culture and inducing substantial differentiation.     

Culture of an epithelial cell line (MDCK) with a serum substitute

This paper reports the suitability of culturing a line of dog kidney epithelial cells, MDCK, in the presence of a serum substitute, Ultroser G. Serial subcultivation with this product was possible for at least 10 passages without any change in cell shape and size, saturation density, dome-forming ability, transepithelial resistance, and growth curve. Adhesion of newly plated cells to plastic was somewhat lower than in fetal calf serum but the trypsin-harvesting kinetics were essentially the same. However, the membrane ion transport systems was alterd: cell sodium influx was greatly diminished, suggesting a deep change in the amiloride-sensitive Na⁺ channels: sodium efflux was highly enhanced (both active and passive).     

乙型肝炎病毒表面抗原在骨髓细胞中的存在及其与乙型肝炎病毒血清复制指标的关联

选择16例血清HBsAg阳性患者为实验组,19例血清HBsAg阴性患者为对照组,每一患者同时采取血清和骨髓涂片,用免疫细胞化学方法(PAP)检测骨髓涂片细胞中的HBsAg。结果,实验组3例骨髓细胞HBsAg阳性者,其血清中HBsAg滴度都很高,而且HBeAg均呈阳性。而在抗HBe阳性或HBeAg/HBeAb阴性者中均无骨髓细胞HBsAg阳性者。在5例血清HBV-DNA多聚酶阳性者中,骨髓细胞中HBsAg阳性者2例;6例多聚酶阴性者中,骨髓细胞中HBsAg阳性者仅1例。 本研究结果证明,HBV可在肝外组织细胞中测出,骨髓细胞HBsAg阳性的出现有集中于HBV高水平复制感染者中的倾向,同时更常见于HBV感染的较早时期。