两种传代细胞系对轮状病毒D36株(P[4]G2)敏感性的比较

目的探讨轮状病毒D36株在MDCK细胞和Vero细胞上培养的适应性,确定其培养的最佳细胞基质及培养条件。方法将D36株以MOI 1.0按不同培养瓶分组接种MDCK细胞和Vero细胞,补充含有不同浓度胰酶的维持液,于不同时间观察两种细胞病变的情况,同时抽样检测病毒滴度,分析两种细胞对D36株的敏感性。结果D36株病毒感染MDCK细胞后第6天病毒滴度达到最高,为(5.00～5.50)lgCCID50/mL;而D36株病毒感染Vero细胞后病毒滴度于第8天达高峰,为(4.50～4.75)lgCCID50/mL。另外,在两种细胞维持液中加入约0.8μg/mL的胰酶均可提高病毒滴度。结论两种细胞系在同等条件下感染D36株病毒后,MDCK细胞比Vero细胞出现病变的时间早,每一批MDCK细胞培养物病毒滴度高于同批次试验的Vero细胞培养物。     

H1N1流感病毒在微载体培养MDCK细胞上增殖的研究

目的探索MDCK细胞在微载体上的培养条件,并研究H1N1型流感病毒在MDCK细胞上的增殖条件。方法在微载体上培养好MDCK细胞上用H1N1型流感病毒在不同的病毒感染复数(MOI)、胰酶浓度两个关键的病毒增殖条件进行流感病毒在细胞上的增殖研究。结果微载体质量浓度为6 g/L时,MDCK细胞培养密度可以达到4.5×106cells/mL。在MOI为0.05接种流感病毒,胰酶质量浓度4μg/mL,流感病毒在MDCK细胞上可获得较高的滴度。结论 MDCK细胞用微载体培养可以达到较高的细胞密度,可以作为规模化生产新型流感病毒疫苗的主要细胞基质进行进一步的研究。     

流感病毒在Vero细胞上的增殖

目的研究流感病毒在非洲绿猴肾细胞(Vero细胞)上高效增殖的最适条件。方法将Vero细胞在50cm2细胞瓶或3000mL旋转瓶中培养成单层,以不同感染复数接种流感病毒,在不同的培养条件下孵育,取上清测病毒血凝滴度。结果当加入胰酶终浓度为40μg·mL-1时,低感染复数接种流感病毒,可获得高效价病毒液,在3000mL旋转培养瓶中流感病毒的易感性较在50cm2静置培养瓶中略高。结论建立了流感病毒在Vero细胞上高效增殖的初步方法。     

A型流感病毒持续感染细胞系来源的IVpi-189病毒生物学性状的初步研究

为明确E61-24-P15 A型重组流感病毒的第189代传代子病毒(IVpi-189)是否具备流感病毒温度敏感减毒活疫苗候选株的特点,将IVpi-189病毒感染MDCK细胞,并于不同培养温度条件下培养,观察其致细胞病变效应,病毒合成、释放情况,以及不同温度条件下病毒存活时间。结果显示32℃培养温度下,IVpi-189病毒具有等同于亲代野生病毒株的诱导细胞病变能力,而当培养温度上调至38℃,IVpi-189病毒致细胞病变效果出现缓慢且程度明显减轻。空斑形成单位实验发现IVpi-189病毒在38℃培养条件下增殖能力明显下降,其原因与病毒灭活速度及子病毒释放无关,但与感染细胞病毒合成能力下降有关。上述实验结果初步证实流感病毒持续感染细胞系来源的IVpi-189病毒具有温度敏感减毒活疫苗的生物学特性,在许可培养温度条件下具有良好的增殖能力,而在非许可培养温度下,病毒增殖活性受到明显抑制。本研究为流感病毒减毒活疫苗的开发研制提供实验佐证。     

Vero细胞培养A/Shanghai/CN02/2013(H7N9)Va流感病毒适宜条件研究

目的:优化Vero细胞培养H7N9流感病毒的培养条件,建立细胞培养病毒高产培养系统。方法:采用不同病毒接种MOI、培养温度、pH值和TPCK胰酶等条件优化培养H7N9流感病毒Vero细胞适应株A/Shanghai/CN02/2013(H7N9)Va的条件,并将其连续传代后扩大至细胞工厂大规模培养。结果:Vero细胞高产H7N9流感病毒培养条件为DMEM/F12和MEM以1∶1混合,并添加0.3 mg/mL牛血清白蛋白、1%谷氨酰胺、0.5%双抗和1.5μg/mL TPCK胰蛋白酶,pH为7.4时,连续传代病毒血凝效价保持在512,扩大至细胞工厂大规模培养病毒产量稳定。结论:建立的Vero细胞培养H7N9流感病毒条件,能够持续稳定高产,并适用于细胞工厂大规模培养,有望用于H7N9流感细胞疫苗的大规模制备。     

重组胰酶在四价流感病毒裂解疫苗(MDCK细胞)制备中的应用

目的 探究使用重组胰酶(recombinant trypsin, RT)替代N-(对甲苯磺酰基)-L-苯基乙基氯甲基酮(N-p-Tosyl-L-phenylalanine chloromethyl ketone, TPCK)处理的牛源胰蛋白酶(TPCK-trypsin, TT),在基于无血清悬浮细胞培养的四价流感病毒裂解疫苗制备中的可行性。方法 用不同浓度的RT处理无血清悬浮培养的犬肾细胞(madin-darby canine kidney cell,简称MDCK细胞),检测其对细胞密度和细胞活力的影响。在流感病毒感染环节添加不同浓度的RT,在不同时间细胞收获病毒液，检测病毒滴度，确定适合的RT浓度。在2μg/mL RT的条件下，接种不同(亚)型流感病毒毒株，以检测不同时间病毒滴度及细胞密度，并在3 L生物反应器中验证RT对流感病毒扩增的影响。结果 当RT浓度<5μg/mL时，对无血清悬浮培养的MDCK细胞生长密度和细胞活力均无显著影响；在病毒感染与扩增过程中，添加终浓度为2μg/mL RT可保证不同(亚)型流感病毒疫苗株的有效扩增。其中，H1N1、H3N2、B/Vic、B/Ya...     

类弹性蛋白多肽的从头设计、非色谱纯化及盐效应

近年来,因病毒侵害人类每年都要蒙受巨大的经济损失和社会损失。犬肾细胞MDCK以其具有的培养容易、增殖快、流感病毒感染效率高等特点,成为适用于流感病毒疫苗生产的重要细胞系之一。以MDCK细胞为研究对象,在自制无血清培养基中成功实现了MDCK细胞从有血清培养到无血清培养的驯化;并通过单细胞悬浮培养驯化过程实现了MDCK细胞的无血清单细胞悬浮培养,获得了适于无血清单细胞悬浮生长的ssf-MDCK细胞株,无血清单细胞悬浮批培养最大活细胞密度可达3.81×106 cells/mL,最大比生长速率可达0.056 h?     

ELISA法检测H3N2亚型流感病毒Vero细胞适应株

目的:流感病毒Vero细胞适应株A/Yunnan/1/2005va(H3N2)是一株以Vero细胞为培养基质能高产的病毒株,可用于制备以Vero细胞为基质的流感病毒裂解灭活疫苗;通过在低温下连续传代培养,可选育出流感病毒Vero细胞冷适应株,用于制备Vero细胞流感病毒减毒活疫苗为了便于对Vero细胞冷适应株的进一步研究,建立一个检测该病毒株的ELISA方法.方法:以流感病毒Vero细胞适应株A/Yunnan/1/2005Va (H3N2)的纯化抗原为免疫原制备羊抗A/Yunnan/1/2005Va (H3N2)和鸡抗A/Yunnan/1/2005Va (H3N2)的抗血清.将抗血清先后经硫酸铵沉淀法和Protein G亲和层析柱纯化后,以纯化的羊抗A/Yunnan/1/2005Va(H3N2) IgG为包被抗体,鸡抗A/Yunnan/1/2005Va(H3N2) IgG为第二抗体,测定包被抗体、第二抗体和酶标抗体最佳工作浓度,建立双抗体夹心ELISA检测方法.结果:羊抗A/Yunnan/1/2005Va (H3N2) IgG的最佳工作浓度为5μg/mL,鸡抗A/Yunnan/1/2005Va(H3N2) IgG的最适浓度为10 μg/mL,酶标抗体最佳稀释倍数为1∶4000.对已知的阳性样品,经双抗体夹心ELISA法测定的病毒滴度比血凝方法测定病毒滴度灵敏度高.结论:通过测定包被抗体、第二抗体和酶标抗体最佳工作浓度,建立了双抗体夹心ELISA检测流感病毒Vero细胞适应株病毒含量的方法.该方法操作简单、方便快速、敏感性高,可应用于Vero细胞冷适应株选育时对流感病毒Vero细胞适应株A/Yunnan/1/2005va(H3N2)的检测,对于研制Vero细胞流感减毒活疫苗有重要意义.     

hTERT基因组成型过量表达的Vero细胞系的建立

目的:建立组成型过量表达hTERT的Vero细胞系。方法:从质粒pCI-neo-hTERT酶切、分离纯化hTERT cDNA,克隆入phEF/chMAR-hyg载体中,构建重组真核表达质粒phEF/chMAR-hyg-hTERT。采用脂质体转染法转染Vero细胞,经潮霉素筛选、克隆分离培养,用RT-PCR检测转染阳性细胞克隆的hTERT mRNA表达丰度,Western blotting验证高丰度表达hTERT mRNA克隆的hTERT表达。用Cedex AS20细胞密度和活力分析系统考察过量表达hTERT Vero细胞在组织培养板中批次培养的生长特性。结果:从phEF/chMAR-hyg-hTERT转染阳性细胞中筛选出hTERT mRNA和蛋白高丰度表达的Vero细胞系(Vero-T1),Vero-T细胞在批次培养中后期的细胞密度和活力均高于野生型Vero细胞。结论:成功建立了hTERT基因组成型过量表达的Vero细胞系,为探索以组成型过量表达hTERT的技术途径改善细胞培养特性、提高病毒疫苗生产工艺水平奠定了基础。     

禽流感病毒H5N1全基因组克隆与分析

为明确广东地区分离的一株禽流感病毒H5N1的遗传背景,建立流感病毒反向遗传的平台。对该株禽流感病毒进行了空斑纯化与组织细胞培养,检测其在MDCK细胞中的增殖特性;利用H5N1病毒通用引物,通过RT-PCR对该病毒全基因组的8条片段进行全长克隆及测序分析;将H5N1的8条全长基因组片段分别插入反向遗传通用载体中,构建禽流感病毒H5N1的感染性克隆。结果表明,该H5N1毒株在MDCK细胞中可不依赖胰酶进行有效增殖与复制,可使MDCK细胞出现典型细胞病变,具有高致病性禽流感病毒的细胞增殖特征。RT-PCR克隆得到该H5N1毒株的PB2、PB1、PA、HA、NP、NA、M和NS八条全长片段,经测序分析确认该毒株的基因序列,其内部编码序列出现多处突变,其中HA连接肽为多个连续碱性氨基酸,表明该毒株可不依赖胰酶进行有效复制,与细胞培养结果一致,未出现抗药性的遗传突变。PCR与测序证明,插入H5N1八个全长基因组片段的载体序列完全正确,表明成功构建了该毒株的感染性克隆。为明确病毒遗传信息,建立流感病毒反向遗传的平台,为进一步研究禽流感病毒相关疫苗提供了研究基础。     

Development and strategies of cell-culture technology for influenza vaccine

Influenza is a pandemic contagious disease and causes human deaths and huge economic destruction of poultry in the world. In order to control and prevent influenza, mainly type A, influenza vaccine for human and poultry were available since the 1940s and 1920s, respectively. In the development of vaccine production, influenza viruses were cultured originally from chicken embryos to anchorage-dependent cell lines, such as MDCK and Vero. The anchorage-independent lines have also been used to produce influenza virus, such as PER.C6 and engineering modified MDCK and Vero. During the process of influenza vaccine production, the common problem faced by all producers is how to improve the titer of influenza virus. This paper focuses on the developments of cell culture for influenza virus vaccine production, limitations of cell culture, and relative strategies for improvement virus yields in cell-culture systems.     

MDCK and Vero cells for influenza virus vaccine production: a one-to-one comparison up to lab-scale bioreactor cultivation

Over the last decade, adherent MDCK (Madin Darby canine kidney) and Vero cells have attracted considerable attention for production of cell culture-derived influenza vaccines. While numerous publications deal with the design and the optimization of corresponding upstream processes, one-to-one comparisons of these cell lines under comparable cultivation conditions have largely been neglected. Therefore, a direct comparison of influenza virus production with adherent MDCK and Vero cells in T-flasks, roller bottles, and lab-scale bioreactors was performed in this study. First, virus seeds had to be adapted to Vero cells by multiple passages. Glycan analysis of the hemagglutinin (HA) protein showed that for influenza A/PR/8/34 H1N1, three passages were sufficient to achieve a stable new N-glycan fingerprint, higher yields, and a faster increase to maximum HA titers. Compared to MDCK cells, virus production in serum-free medium with Vero cells was highly sensitive to trypsin concentration. Virus stability at 37 °C for different virus strains showed differences depending on medium, virus strain, and cell line. After careful adjustment of corresponding parameters, comparable productivity was obtained with both host cell lines in small-scale cultivation systems. However, using these cultivation conditions in lab-scale bioreactors (stirred tank, wave bioreactor) resulted in lower productivities for Vero cells.     

The expression of essential components for human influenza virus internalisation in Vero and MDCK cells

MDCK and Vero cell lines have been used as substrates for influenza virus replication. However, Vero cells produced lower influenza virus titer yield compared to MDCK. Influenza virus needs molecules for internalisation of the virus into the host cell, such as influenza virus receptor and clathrin. Human influenza receptor is usually a membrane protein containing Sia(α2,6) Gal, which is added into the protein in the golgi apparatus by α2,6 sialyltransferase (SIAT1). Light clathrin A (LCA), light clathrin B (LCB) and heavy clathrin (HC) are the main components needed for virus endocytosis. Therefore, it is necessary to compare the expression of SIAT1 and clathrin in Vero and MDCK cells. This study is reporting the expression of SIAT1 and clathrin observed in both cells with respect to the levels of (1) RNA by using RT-PCR, (2) protein by using dot blot analysis and confocal microscope. The results showed that Vero and MDCK cells expressed both SIAT1 and clathrin proteins, and the expression of SIAT1 in MDCK was higher compared to Vero cells. On the other hand, the expressions of LCA, LCB and HC protein in MDCK cells were not significantly different to Vero cells. This result showed that the inability of Vero cells to internalize H1N1 influenza virus was possibly due to the lack of transmembrane protein receptor which contained Sia(α2,6) Gal.     

MDCK细胞的悬浮驯化及初步应用

目的：驯化MDCK细胞使之适应悬浮培养,以之作为生产流感病毒疫苗的介质,为以细胞代替鸡胚制备流感病毒疫苗提供保证。方法：通过直接法和间接法分别驯化MDCK细胞,放大培养能悬浮生长的MDCK细胞,并以之作为介质培养流感病毒。结果：获得了能悬浮培养的MDCK细胞,其在悬浮条件下生长良好;以之作为载体培养流感病毒,可获得较高产量的病毒。结论：建立了悬浮培养的MDCK细胞,以之作为载体培养流感病毒可获得较高病毒滴度,为细胞培养生产流感病毒疫苗奠定了基础。     

肠道病毒71型在RD细胞和Vero细胞中的增殖动力学特征

目的:利用噬斑法比较肠道病毒71型(EV71)在RD细胞和Vero细胞中的增殖动力学特征。方法:首先探讨培养基类型、羟乙基哌嗪乙磺酸(HEPES)、胎牛血清(FBS)、牛血清白蛋白(BSA)及甲基纤维素(MC)含量对EV71噬斑形成的影响,得到最适营养覆盖物配比;进一步,EV71以感染复数(MOI)为0.1分别接种RD细胞和Vero细胞,收集接种后不同时间点的细胞培养液,噬斑法测定各时间点培养液上清中的病毒滴度,并绘制log2(病毒滴度)-时间图,对比分析EV71在2种细胞中的增殖动力学特征。结果:终浓度含1%MC和2%FBS的MEM(1×)或DMEM(1×)为EV71噬斑形成的最适营养覆盖物;EV71在RD细胞和Vero细胞中的增殖周期均约为12 h,MOI=0.1时,EV71在RD细胞中的增殖活动较Vero细胞中活跃,增殖效率比Vero细胞中高2个数量级。结论:用RD细胞扩增EV71比Vero细胞更具优势。     

中华蜜蜂幼虫原代细胞培养及中华蜜蜂囊状幼虫病毒在培养的细胞中的复制

【目的】建立一种适用于蜜蜂源的细胞培养方法,为蜜蜂源细胞培养和蜂病毒的研究奠定基础。【方法】比较在Grace和WH2两种昆虫细胞培养基中培养的中华蜜蜂 Apis cerana cerana 幼虫原代细胞状况,筛选出适用于中华蜜蜂幼虫原代细胞培养的最佳培养基,并通过细胞活力比较,确定用于中华蜜蜂幼虫原代细胞培养的适宜胎牛血清(fetal bovine serum, FBS)浓度。在此基础上,用该原代细胞接种中华蜜蜂囊状幼虫病毒（Chinese sacbrood bee disease, CSBV）,并通过实时定量RT-PCR方法对病毒复制情况进行检测。【结果】相对于WH2培养基,在Grace培养基中生长的细胞大而圆,透明,边缘整齐,无颗粒物,活力明显高于WH2培养,且含15% FBS的Grace培养基更适合于中华蜜蜂幼虫原代细胞培养。CSBV接种在该原代细胞,能够复制增殖,同时伴随宿主细胞快速分裂。【结论】中华蜜蜂幼虫原代细胞培养基在含15%FBS的Grace中能够良好生长,并且CSBV可以在该原代细胞中进行复制。     

Overexpression of the alpha-2,6-sialyltransferase in MDCK cells increases influenza virus sensitivity to neuraminidase inhibitors

No reliable cell culture assay is currently available for monitoring human influenza virus sensitivity to neuraminidase inhibitors (NAI). This can be explained by the observation that because of a low concentration of sialyl-alpha2,6-galactose (Sia[alpha2,6]Gal)-containing virus receptors in conventional cell lines, replication of human virus isolates shows little dependency on viral neuraminidase. To test whether overexpression of Sia(alpha2,6)Gal moieties in cultured cells could make them suitable for testing human influenza virus sensitivity to NAI, we stably transfected MDCK cells with cDNA of human 2,6-sialyltransferase (SIAT1). Transfected cells expressed twofold-higher amounts of 6-linked sialic acids and twofold-lower amounts of 3-linked sialic acids than parent MDCK cells as judged by staining with Sambucus nigra agglutinin and Maackia amurensis agglutinin, respectively. After transfection, binding of a clinical human influenza virus isolate was increased, whereas binding of its egg-adapted variant which preferentially bound 3-linked receptors was decreased. The sensitivity of human influenza A and B viruses to the neuraminidase inhibitor oseltamivir carboxylate was substantially improved in the SIAT1-transfected cell line and was consistent with their sensitivity in neuraminidase enzyme assay and with the hemagglutinin (HA) receptor-binding phenotype. MDCK cells stably transfected with SIAT1 may therefore be a suitable system for testing influenza virus sensitivity to NAI.