负载肿瘤抗原的DC体外诱导抗肿瘤免疫反应的实验研究

目的 研究自体及同种异体树突状细胞(DC)体外负载肿瘤抗原后刺激T淋巴细胞增殖及诱导抗肿瘤免疫反应的能力.方法 利用细胞因子诱导人骨髓单个核细胞生成DC,尼龙毛柱法分离T淋巴细胞,3H-TdR掺入法检测负载肺癌细胞凋亡小体的自体及同种异体DC体外刺激T细胞增殖反应,乳酸脱氢酶(LDH)释放法检测负载肺癌细胞凋亡小体的自体及同种异体DC刺激的T细胞对肺癌细胞和乳腺癌细胞系MCF-7的杀伤作用.结果 骨髓细胞诱生的自体及同种异体DC负载肿瘤抗原后,均具有刺激T淋巴细胞增殖的能力,负载肿瘤抗原的自体及异体DC激活的T淋巴细胞后均可杀伤两种靶细胞,T细胞对MCF-7的杀伤力明显低于对患者肺癌细胞的杀伤力. 结论人自体或异体DC体外负载细胞性肿瘤抗原后,可有效地刺激T淋巴细胞的增殖,产生特异性肿瘤杀伤作用.     

树突状细胞介导的T细胞抗多发性骨髓瘤细胞活性的研究

多发性骨髓瘤（MM）是B细胞来源的恶性肿瘤。化疗和造血干细胞移植等综合治疗，可获得较高的缓解率，但微小残留病的存在，使骨髓瘤易复发。树突状细胞（DC）为基础的免疫治疗是近几年来治疗MM的热点之一。国外报道用凋亡的骨髓瘤细胞或分泌的异常单克隆Ig，即M蛋白脉冲DC，得到DC瘤苗，再回输体内，可以观察到骨髓瘤特异的抗瘤效应。本实验体外诱导培养DC，负载骨髓瘤细胞全抗原或分泌的M蛋白，探讨负载抗原的DC对淋巴细胞的活化作用及活化的淋巴细胞对自体、异体骨髓瘤细胞的杀伤活性。     

两种不同抗原致敏方式负载DC疫苗对Lovo细胞的体外杀伤作用

目的比较重组痘苗病毒负载人癌胚抗原（CEA）基因转染方式与Lovo细胞裂解物诱导方式对产生DC疫苗的影响。方法分别采用重组痘苗病毒负载CEA基因转染方式及Lovo肿瘤细胞裂解物转染方式转染未成熟DC,诱导特异性细胞毒性T淋巴细胞（CTL）。体外培养CTL并检测其活性;MTT法检测两组CTL对kovo细胞的杀伤作用。结果两种方式致敏DC均可诱导激活CTL并分泌INF-γ,而重组痘苗病毒转染Dc组CTL诱导率高于细胞裂解物组;重组痘苗病毒转染组诱导的CTL对Lovo细胞的特异性杀伤活性显著高于细胞裂解物组。结论两种不同抗原致敏方式负载DC疫苗均能够诱导高效而特异的CTL杀瘤活性,而使用重组痘苗病毒转染CEA至DCs的方式明显优于肿瘤细胞裂解物的抗原负载方式,为DC疫苗用于结肠癌的免疫治疗奠定基础。     

负载食管癌抗原的DC诱导特异性CTL对食管癌细胞体外杀伤作用观察

目的观察负载食管癌抗原的树突状细胞（DC）活化的特异性细胞毒性T淋巴细胞（CTLs）对食管癌细胞的体外杀伤作用。方法冻融法获取食管癌细胞抗原,联合应用粒细胞—巨噬细胞集落刺激因子（rhGM-CSF）、白细胞介素4（IL-4）和肿瘤坏死因子α（TNF-α）诱导培养外周血DC并负载肿瘤抗原,激活自体T淋巴细胞,制备特异性CTLs。将其加入食管癌细胞中培养48 h,用MTT法检测食管癌细胞裂解率,ELISA法检测γ干扰素（γ-IFN）水平。结果负载食管癌抗原的DC激活的CTLs表现出对食管癌Eca109细胞的特异性杀伤作用,γ-IFN水平为（1 625±37.55）pg/ml;而对A549细胞仅有微弱的杀伤作用,γ-IFN水平为（169.04±13.81）pg/ml。未负载食管癌抗原DC刺激的CTLs对食管癌细胞几无杀伤作用。结论负载食管癌抗原的DC激活的CTLs在体外对食管癌细胞能产生高效而特异性的杀伤作用。     

丝裂霉素诱导凋亡癌细胞致敏树突状细胞后的免疫应答

目的 观察树突状细胞(DC)从丝裂霉素诱导的凋亡胆管癌细胞获取抗原后,抗肿瘤免疫应答及对胆管癌细胞的特异性免疫杀伤效果。 方法 用粒细胞-巨噬细胞集落刺激因子(GM-CSF)加IL-4从人外周血分化、诱导DC,丝裂霉素在体外诱导培养的人胆管癌细胞凋亡,将DC、T淋巴细胞和凋亡胆管癌细胞共培养,同时设计不同类型肿瘤细胞(坏死胆管癌细胞及培养胆管癌细胞)作对照,7d后,分离、富集DC、T淋巴细胞进行免疫应答及肿瘤细胞杀伤试验。 结果 与凋亡胆管癌细胞共培养的DC可以有效提呈胆管癌细胞抗原,有强烈的免疫应答,刺激的细胞毒T淋巴细胞特异性地杀伤胆管癌细胞。 结论 丝裂霉素诱导凋亡癌细胞可以致敏rhGM-CSF加rhIL-4从人外周血单个核细胞诱导、扩增出的DC,并产生显著的杀伤胆管癌细胞的免疫反应,可望成为特异性免疫治疗肿瘤的一条新途径。     

凋亡U937细胞负载的树突细胞介导的免疫应答

目的:探讨凋亡U937细胞负载的树突细胞(DC)能否介导抗白血病免疫应答。方法:用紫外线辐照诱导U937细胞凋亡。从正常人外周血单个核细胞诱生DC,用凋亡的U937细胞负载DC并添加肿瘤坏死因子-α(TNF-α)诱导DC成熟,然后与自体T淋巴细胞共育,并联合白细胞介素(IL)-2以诱生肿瘤特异性细胞毒T淋巴细胞(CTL)。采用免疫荧光标记和流式细胞术测定DC膜分子的表达;Dextran-FITC内吞试验检测DC的抗原摄取能力;用ELISA法检测IL-12p70的产生;采用MTT法分别检测CTL的增殖和细胞毒效应。结果:U937细胞经紫外线辐照后培养2h,凋亡指数明显增高,并于照射后4～8h时达高峰(56.61%～66.96%)。DC在未成熟阶段时吞噬Dextran-FITC的能力最强,负载凋亡U937细胞之后并不能促使未成熟DC(i DC)分化为成熟DC(mDC)。凋亡U937细胞负载后的i DC在TNF-α的作用下成为mDC后其分泌IL-12p70显著增加的同时可显著诱导T细胞增殖生成对U937细胞具有特异杀伤作用的CTL。结论:凋亡细胞负载的DC能有效地诱导抗白血病效应。     

负载胰腺癌抗原的树突状细胞疫苗诱导T淋巴细胞抗肿瘤效应的研究

培养树突状细胞(DC),反复冻融法裂解培养的负载胰腺癌细胞(PC-3),提取细胞抗原,致敏DC,获得负载胰腺癌抗原的DC疫苗后诱导特异性细胞毒性T淋巴细胞(CTL)的生成,MTT法检测CTL对不同肿瘤细胞的杀伤作用.发现负载PC-3细胞抗原的DC疫苗能诱导产生肿瘤特异性的CTL,其对PC-3细胞具有明显地杀伤效应,而对人乳腺癌细胞MCF-7、人肝癌细胞7721细胞杀伤作用弱.认为负载胰腺癌抗原的DC疫苗能够诱导高效而特异地CTT杀瘤活性,为将来DC疫苗在胰腺癌的免疫治疗中提供了实验依据.     

体外负载冻融抗原的脐血树突状细胞诱导的抗肝癌效应

目的评价体外应用肝癌细胞冻融抗原负载的脐血树突状细胞（DC）所诱导的抗肝癌效应。方法采集健康足月剖宫产孕妇胎盘端脐血,分离脐血单个核细胞（CBMNC）及T淋巴细胞,用GM-CSF、IL-4及TNF-α联合诱导CBMNC分化为DC,观察形态学变化并以流式细胞术鉴定,选培养的第3天以肝癌细胞冻融抗原负载的CBMNC-DC,以负载抗原的DC刺激自体淋巴细胞活化为自体细胞毒性T淋巴细胞（CTL）,并用CTL对肝癌细胞进行杀伤,MTT法测定活化的自体淋巴细胞的相对数量和CTL对肝癌细胞的杀伤率。结果体外负载肿瘤冻融抗原的脐血DC可诱导显著的自体效应淋巴细胞增殖及抗肝癌效应。结论体外负载抗原的脐血DC可诱导显著的抗肝癌效应,是具有临床应用前景的肝癌疫苗。     

树突状细胞负载肝癌相关抗原后成熟调控的研究

目的 研究树突状细胞（DC）负载肝癌相关抗原后的成熟调控。方法 用SDS－PAGE制备电泳纯化牛结核分枝杆菌热休克蛋白70，用其诱导DC的分化与成熟。结果 DC负载肝癌可溶性抗原后，10％2细胞失去了DC特征，同时其表面CD54（90．0％），CD83（78．0％），CD86（85．0％）分子表达下降；牛分枝杆菌卡介苗－热休克蛋白70（BCG HSP70）的活化有利于负载肝癌可溶性抗原后的DC维持其特异性标志，同时DC表面CD54（92．0％），CD83（90．0％），CD86（91．0％）分子表达增加，DC诱导同种异体淋巴细胞转化的能力增加，淋巴细胞增殖加快，从而促进DC成熟，增加其抗原呈递能力。结论 预示BCG HSP70有可能成为促进DC活化和成熟的另一重要分子。     

胰腺癌细胞总RNA转染树突细胞诱导特异性CTL能力的体外研究

目的观察人胰腺癌Mia Pa Ca-2细胞总RNA电转染树突细胞(Dendritic Cell,DC)体外激发抗原特异性细胞毒T淋巴细胞(Cytotoxic T Lymphocyte,CTL)的能力。方法自6例胰腺癌患者外周血单核细胞中分离、培养DC。使用电穿孔法将Mia Pa Ca-2细胞总RNA体外转录和PCR扩增的MUC1m RNA转染DC,以未负载抗原的DC为对照。采用实时定量PCR技术检测各组DC中MUC1表达。四甲基偶氮唑盐(MTT)检测转染各组DC存活率变化;混合细胞培养法评价各组DC体外刺激自体T淋巴细胞增殖能力;ELISA法检测各组DC体外激发抗原特异性CTL细胞因子释放量。结果 Mia Pa Ca-2总RNA与MUC1 m RNA分别转染后48 h DC中目标抗原的相对表达量分别为37.24±3.17和34.53±2.02,两者比较无显著差异(P0.05)。电转染后96 h Mia Pa Ca-2总RNA转染组DC存活率降至60.81%,低于MUC1 m RNA单转染时DC的存活率(80%左右)(P0.05)。转染Mia Pa Ca-2总RNA DC刺激自体T细胞增殖指数为8 432±611.25,显著高于MUC1单独转染组3 664±305.17(P0.05);且转染Mia Pa Ca-2总RNA DC激发特异性CTL分泌IL-2、IL-10、Granzyme B、IFN-γ水平亦显著高于MUC1 m RNA单独转染组(P0.05)。结论胰腺癌肿瘤细胞总RNA转染的DC较单一胰腺癌相关抗原负载DC有更强的体外抗原特异性CTL激发能力。     

消化系恶性肿瘤病人LAK细胞和NK细胞功能与表型的变化

通过观察20例正常人和24例消化系恶性肿瘤病人外周血自然杀伤细胞(NK)和淋巴因子激活的杀伤细胞(LAK)的活性变化,以及加用重组白细胞介素2(rIL-2)刺激前后T淋巴细胞表型变化。结果发现肿瘤病人的NK细胞活性明显下降,但经rIL-2激活后LAK细胞活性得到明显提高,其溶解率接近正常水平。肿瘤病人的总T淋巴细胞(CD_(3+))和辅助/诱导T淋巴细胞(CD_(4+))水平低于正常,但抑制/杀伤淋巴细胞(CD_(8+))水平正常。辅助/诱导淋巴细胞与抑制/杀伤淋巴细胞之比为1.18,低于正常水平(1.55)。经加入rIL-2培养后,CD_(3+)和CD_(8+)淋巴细胞的比率明显升高并达正常水平。而在正常人此变化不明显,且加用rIL-2培养与不加者无显著差异。IL-2受体的表达正常人与肿瘤病人无异。结果显示胃肠道恶性肿瘤病人的免疫机制受到抑制,但能被IL-2提高至正常水平。     

MicroRNA-224 is upregulated in HepG2 cells and involved in cellular migration and invasion

Background and Aim:  MicroRNAs are a class of small non-coding RNAs that negatively regulate the expression of their target genes. The aim of the present study was to explore the effects of microRNA on biological behaviors of HepG2 cells and further analyze its characteristics.
Methods:  We detected different expression profiles of miRNAs in HepG2 and L02 cell lines by microRNA microarray. Northern blot, quantitative real-time polymerase chain reaction, methylthiazolyl tetrazolium, fluorescence-activated cell sorting, scratch wound, transwell migration and Matrigel invasion assays and western blot were carried out to determine whether or not microRNA-224 ( miR-224 ) can influence the biological behaviors of HepG2 cells.
Results:  MiR-224 was significantly upregulated in HepG2 cells. Cell proliferation, migration and invasion, but not cell cycles, were altered after changing the expression of miR-224 . Taking invasion and migration as a breakthrough, a close relationship between the expression of miR-224 and its proteins such as PAK 4 and MMP9 , which were involved in the invasion of tumor, was found.
Conclusions:  Overexpression of miR-224 was involved in the malignant phenotype of HepG2 cells, and it may be an important factor in regulating the migration and invasion of HepG2 cells.     

Dynamic FtsA and FtsZ localization and outer membrane alterations during polar growth and cell division in Agrobacterium tumefaciens

Growth and cell division in rod-shaped bacteria have been primarily studied in species that grow predominantly by peptidoglycan (PG) synthesis along the length of the cell. Rhizobiales species, however, predominantly grow by PG synthesis at a single pole. Here we characterize the dynamic localization of several Agrobacterium tumefaciens components during the cell cycle. First, the lipophilic dye FM 4-64 predominantly stains the outer membranes of old poles versus growing poles. In cells about to divide, however, both poles are equally labeled with FM 4-64, but the constriction site is not. Second, the cell-division protein FtsA alternates from unipolar foci in the shortest cells to unipolar and midcell localization in cells of intermediate length, to strictly midcell localization in the longest cells undergoing septation. Third, the cell division protein FtsZ localizes in a cell-cycle pattern similar to, but more complex than, FtsA. Finally, because PG synthesis is spatially and temporally regulated during the cell cycle, we treated cells with sublethal concentrations of carbenicillin (Cb) to assess the role of penicillin-binding proteins in growth and cell division. Cb-treated cells formed midcell circumferential bulges, suggesting that interrupted PG synthesis destabilizes the septum. Midcell bulges contained bands or foci of FtsA-GFP and FtsZ-GFP and no FM 4-64 label, as in untreated cells. There were no abnormal morphologies at the growth poles in Cb-treated cells, suggesting unipolar growth uses Cb-insensitive PG synthesis enzymes.     

Measurement of adherent cell mass and growth

The characterization of physical properties of cells such as their mass and stiffness has been of great interest and can have profound implications in cell biology, tissue engineering, cancer, and disease research. For example, the direct dependence of cell growth rate on cell mass for individual adherent human cells can elucidate the mechanisms underlying cell cycle progression. Here we develop an array of micro-electro-mechanical systems (MEMS) resonant mass sensors that can be used to directly measure the biophysical properties, mass, and growth rate of single adherent cells. Unlike conventional cantilever mass sensors, our sensors retain a uniform mass sensitivity over the cell attachment surface. By measuring the frequency shift of the mass sensors with growing (soft) cells and fixed (stiff) cells, and through analytical modeling, we derive the Young's modulus of the unfixed cell and unravel the dependence of the cell mass measurement on cell stiffness. Finally, we grew individual cells on the mass sensors and measured their mass for 50+ hours. Our results demonstrate that adherent human colon epithelial cells have increased growth rates with a larger cell mass, and the average growth rate increases linearly with the cell mass, at 3.25%/hr. Our sensitive mass sensors with a position-independent mass sensitivity can be coupled with microscopy for simultaneous monitoring of cell growth and status, and provide an ideal method to study cell growth, cell cycle progression, differentiation, and apoptosis.     

一种简便实用的大鼠Kupffer细胞的分离与鉴定方法

目的：研究一种简便实用的大鼠Kupffer细胞（KCs）的分离与鉴定方法.方法：原位两步灌流法对大鼠肝脏进行冲洗消化;利用Percoll液进行不连续密度梯度离心分离KCs;;选择性贴壁纯化KCs;台盼蓝染色法鉴定细胞存活率;吞噬实验鉴定细胞功能;ED1单克隆抗体免疫荧光细胞化学鉴定KCs;显微镜下观察KCs形态变化.结果：获取的KCs数量为（2.41±0.32）×107/只,其中活细胞数量占（92.3±2.12）％;吞噬实验显示（95.2±2.58）％的细胞内存在碳素颗粒;免疫荧光化学检测证明KCs纯度为（96.3±1.46）％;在显微镜下观察KCs形态,36h细胞形态变得不规则,3d后呈星形或多角形,体外培养可以存活7～10d.结论：此种KCs分离方法操作相对简便,获取的细胞数量、活性功能、纯度等方面均能达到进一步的实验要求,值得推广.     

单细胞测序技术及其在心血管研究方面的应用

单细胞测序在单个细胞水平研究细胞异质性以及生物多样性。与传统测序研究群体细胞基因的平均变化相比,充分展现了单个细胞间的差异性。近几年来,单细胞测序技术为单个细胞水平研究细胞命运谱系、动态分析细胞异质性、寻找心血管疾病治疗的新靶点、明确干细胞移植标准等提供了有力的帮助。本文介绍了单细胞测序的主要类型,并结合其在心血管研究方面的应用进行了综述。     

Basics and applications of stem cells in the pancreas

Enormous efforts have been made to establish pancreatic stem/progenitor cells as a source for regenerative medicine for the treatment of diabetes mellitus. In recent years, it has been recognized that the self-renewal of beta cells is the dominant process involved in postnatal beta-cell regeneration and expansion. Nevertheless, several in-vitro studies have suggested that ductal or as yet unidentified cells are candidates for pancreatic stem/progenitor cells that can differentiate into multilineage cells, including insulin⁺ cells. The question remains as to whether beta cells are generated postnatally from stem/progenitor cells other than pre-existing beta cells. Furthermore, mutated pancreatic stem cells are considered to be prospective candidates for cancer stem cells or tumor-initiating cells. This review highlights recent progress in pancreatic stem/progenitor cell research.     

Liver cell adenoma and liver cell adenomatosis

During the last three decades liver cell adenoma and liver cell adenomatosis have emerged as new clinical entities in hepato-logical practice due to the widespread use of oral contraceptives and increased imaging of the liver. On review of published series there is evidence that 10% of liver cell adenomas progress to hepatocellular carcinoma, diagnosis is best made by open or laparoscopic excision biopsy, and the preferred treatment modality is resection of the liver cell adenoma to prevent bleeding and malignant transformation. In liver cell adenomatosis, the association with oral contraceptive use is not as high as in solitary liver cell adenomas. The risk of malignant transformation is not increased compared with solitary liver cell adenomas. Treatment consists of close monitoring and imaging, resection of superficially located, large (>4 cm) or growing liver cell adenomas. Liver transplantation is the last resort in case of substantive concern about malignant transformation or for large, painful adenomas in liver cell adenomatosis after treatment attempts by liver resection.     

The role of stem cells in liver injury and repair

ABSTRACT

Introduction: Liver disease is an increasing cause of worldwide mortality, and currently the only curative treatment for end-stage liver disease is whole organ allograft transplantation. Whilst this is an effective treatment, there is a shortage of suitable grafts and consequently some patients die whilst on the waiting list. Cell therapy provides an alternative treatment to increase liver function and potentially ameliorate fibrosis.

Areas covered: In this review, we discuss the different cellular sources for therapy investigated to date in humans including mature hepatocytes, hematopoietic stem cells, mesenchymal stromal cells and hepatic progenitor cells. Cells investigated in animals include embryonic stem cells, induced pluripotent stem cells and directly reprogrammed cells. We then appraise the experience and evidence base underlying each cell type.

Expert opinion: We discuss how this field may evolve in the years to come focusing on opportunities to enhance the intrinsic regenerative response with therapeutic targets and cell therapies. Growing expertise in tissue engineering will likely lead to increasingly complex bio-reactors and bio-artificial livers, which open a further avenue to restore liver function and delay or prevent the need for transplantation.