通过受体介导法将核酶特异导入肝细胞以阻断HBV蛋白表达的初步研究

应用半乳糖末端糖蛋白受体（ＡＳＧＰ－Ｒ）介导的内吞作用，将外源基因导入真核细胞，与脂质体介导的转染和细胞表面转铁蛋白受体（Ｔｆ－Ｒ）介导的内吞作用相比，虽然三种方式均能有效介导外源基因的转移，但ＡＳＧＰ－Ｒ法具有肝细胞特异性，而脂质体法和Ｔｆ－Ｒ法不具此特性。将克隆于真核表达载体的针对乙型肝炎病毒（ＨＢＶ）ｍＲＮＡＰｒｅＣ／Ｃ区的核酶质粒ｐＣＭＶ－Ｒｉｐｃ特异性导入肝细胞并发挥作用，通过酶联免疫吸附法（ＥＬＩＳＡ）检测细胞培养液中的乙型肝炎表面抗原（ＨＢｓＡｇ）和ｅ抗原（ＨＢｅＡｇ），评价核酶在细胞水平对ＨＢＶ抗原表达的阻断作用。结果表明当核酶质粒ｐＣＭＶ－Ｒｉｐｃ与ＨＢＶ抗原表达质粒ｐＵＣ－２ＨＢＶ共转染ＨｅｐＧ２细胞时，核酶对ＨＢｓＡｇ和ＨＢｅＡｇ表达的抑制率分别为５５．２９％和６８．７３％。     

应用重组质粒pAM－HBsAg在果蝇细胞中表达乙型肝炎病毒表面抗原及基因免疫的初步研究

应用果蝇（ＤＳ２）表达系统，构建了含有乙型肝炎病毒表面抗原（ＨＢｓＡｇ）、摄金蛋白启动子（ＭＴｎ－ｐｒｏｍｏｔｅｒ）的共表达质粒ｐＡＭ－ＨＢｓＡｇ，转染细胞，经克隆，存活细胞株的培养上清液经硫酸铵沉淀、氯化铯（ＣＳＣｌ）密度梯度离心沉淀，获得的抗原用酶联免疫吸附试验（ＥＬＩＳＡ）、放射免疫分析（ＲＩＡ）法检测抗体，免疫吸印法（Ｗｅｓｔｅｒｎｂｌｏｔ）和电泳凝胶银染显色证实分子量为２３０００和２７０００，免疫电镜观察显示表达产物为２２ｕｍ球型颗粒，通过重金属离子（ＣｕＳＯ４、ＺｎＳＯ４）的诱导可增加抗原的表达量。用共表达质粒ｐＡＭ－ＨＢｓＡｇ的ＤＮＡ，注射Ｂａｌｂ／Ｃ小鼠的股四头肌。经ＥＬＩＳＡ、ＲＩＡ检测抗体产生情况，结果免疫后的小鼠经硫酸锌喂养抗体高于普通喂养的小鼠。Ｓｏｕｔｈｅｒｎ杂交证实鼠肌肉细胞存在ＨＢｓＡｇ基因。小鼠免疫接种实验表明，ＤＳ２细胞表达的抗原与直接用ＤＮＡ含有ＨＢｓＡｇ的重组质粒）免疫小鼠均获抗ＨＢｓＡｇ的抗体。     

PA－MSHA菌苗对小鼠免疫活性细胞的作用

ＰＡ－ＭＳＨＡ菌苗对小鼠免疫活性细胞的作用锦州医学院微生物学教研室（锦州１２１００１）张明策，牟希亚ＰＡ－ＭＳＨＡ（Ｐｓ．ａｅｒｕｇｉｎｏｓａｗｉｔｈｍａｎｎｏｓｅｓｅｎｓｉ－ｔｉｖｅｈｅｍａｇｇｌｕｔｉｎａｔｉｏｎｐｉｌｌ，ＰＡ－ＭＳＨＡ）菌苗是携...     

巴西甲肝病毒（HAF－203）在灵长目细胞系上的快速生长

巴西甲肝病毒（ＨＡＦ－２０３）在灵长目细胞系上的快速生长［英］／ＧａｓｐａｒＡＭ…ＢｒａｚＪＭｅｄＢｉｏｌＲｅｓ．－１９９３，２６（２）．－２０３～２０６将巴西分离的一株甲型肝炎病毒（ＨＡＶ，ＨＡＦ－２０３）接种到ＦＲｈｋ４细胞（恒河猴胚肾细胞）并传...     

红景天甙对缺氧状态下兔肺动脉平滑肌细胞增殖和c—fos,c— …

目的：研究红景天甙对缺氧（２－３％）状态下兔肺动脉平滑肌细胞（ＰＡＳＭＣ）增殖、ＤＮＡ合成、细胞周期和ｃ－ｆｏｓ、ｘ－ｍｙｃ原癌基因表达的影响。方法：应用细胞培养，四唑盐比色试验（ＭＴＴ），「＾３Ｈ」－胸腺嘧啶核苷（「＾３Ｈ」－ＴｄＲ）掺入、细胞周期测定和斑 交的方法。结果：发现缺氧２４ｈ可直接刺激ＰＡＳＭＣ，使ＭＴＴ之ＯＤ值增加９５％，「＾３Ｈ」－ＴｄＲ的掺入量增加１４０％；在缺氧的ＰＡＳＭＣ培     

人巨细胞病毒感染对肾移植受者血清sIL－2R水平的影响

用ＰＣＲ检测ＨＣＭＶ－ＤＮＡ，ＥＬＩＳＡ法检测ＨＣＭＶ－ＩｇＭ及ＩｇＧ，以诊断肾移植受者ＨＣＭＶ感染。用双抗体夹心法ＥＬＩＳＡ检测６５例肾移植受者血清ｓＩＬ－２Ｒ水平，结果表明：ＨＣＭＶ感染后宿主血清ｓＩＬ－２Ｒ水平明显增高（Ｐ＜０．０１），且ＨＣＭＶ疾病组ｓＩＬ－２Ｒ增高程度大于无症状感染组（Ｐ＜０．０１）；６例原发性ＨＣＭＶ感染者ｓＩＬ－２Ｒ水平与ＩｇＭ水平呈正相关（ｒ＝０．９９０８），提示随感染程度增加，血清ｓＩＬ－２Ｒ水平随之增高，还发现血清ｓＩＬ－２Ｒ水平与Ｃ９４／ＣＤ８比值是负相关（ｒ＝－０．９７８９），说明ＨＣＭｖ感染后ｓＩＬ－２Ｒ水平增高与Ｔ细胞亚群改变有关，反之也说明ｓＩＬ－２Ｒ增高程度可表明体内免疫抑制状态。对于ＨＣＭＶ感染后血清ｓＩＬ－２Ｒ水平增高的机理有待进一步探讨。     

针对包装信号起始区的硫代反义核苷酸抗HBV的研究

目的筛选高效特异的抗ＨＢＶ反义核酸药物。方法针对ＨＢＶ包装信号ε起始区设计并合成硫代反义寡聚核苷酸（ｓ－ａｓＯＤＮ）片段，通过ＥＬＩＳＡ检测法、ＭＴＴ法、电子显微镜等观察，研究此ｓ－ａｓＯＤＮ对ＨＢｓＡｇ、ＨＢｅＡｇ和ＨＢｃＡｇ表达，以及对细胞毒性，细胞形态的影响。结果针对ε起始区的ｓ－ａｓＯＤＮ显著抑制ＨＢｓＡｇ、ＨＢｅＡｇ和ＨＢｃＡｇ的表达，其中，对ＨＢｅＡｇ和ＨＢｃＡｇ的抑制率分别为３８．１％和５８．７％高于Ｓ基因起始区（３２．１％和３７．２％，Ｐ＜０．０１），对ＨＢｓＡｇ抑制率为８２％，低于Ｓ基因起始区（９３．４１％），在实验浓度下ｓ－ａｓＯＤＮ对细胞无毒性，对细胞形态无影响。结论ＨＢＶ包装信号区是反义核酸抗ＨＢＶ复制研究的重要的靶序列选择区域。     

抗病毒蛋白MxA的诱导和检测方法的实验研究

目的 研究抗病毒蛋白ＭｘＡ的表达及其活性。方法用ＩＦＮα２ｂ或３型腺病毒（Ａ＿３）分别对ＷＩ－３８细胞或人外周血单个核细胞（ＰＢＭＣｓ）作用 １２或２４ ｈ，并用Ｗｅｓｔｅｍ ｂｌｏｔ法或ＦＡＣＳ法，分别对Ｍ蛋白的表达进行定性和定量检测。采用微量细胞病变抑制法，对重组的ＭｘＡ和ＩＦＮα２ｂ进行抗病毒效应实验。结果 （１）低浓度的 ＩＦＮα２ｂ（＞ １×1０～＃ＩＵ／Ｌ）和Ａｄ＿３（＞２００ ＴＣＩＤ＿５０），均可诱导相应细胞表达 ＭｘＡ；（２）１０μｇ／Ｌ ＭｘＡ可抵抗２０个 ＴＣＩＤ＿（５０）的 ＨＳＶ－Ｉ、Ｐｏｌｉｏ． Ｖ感染 Ｖｅｒｏ细胞、Ａｄ＿３感染ＨｅＬａ细胞，抵抗２００个ＴＣＩＤ＿（５０）的ＶＳＶ感染Ｗｉｓｈ细胞。结论ＭｘＡ只能由干扰素（ＩＮＦα2ｂ）或病毒诱导产生，其具有广谱的抗病毒活性。     

TLSFJM对PMA诱导Jurkat细胞IL—2Ra链基因表达的抑制作用

本文应用原位杂交和双ＭｃＡｂ夹心ＥＬＩＳＡ方法，探讨了来自ＪＭＴ细胞白血病细胞系产生的抑制因子（ＴＬＳＦＪＭ）对ＰＭＡ诱导的Ｊｕｒｋａｔ细胞ＩＬ－２Ｒａ链基因表达的影响。结果表明：ＴＬＳＦＪＭ可明显抑制ＰＭＡ诱导的ｊｕｒｋａｔ细胞ＩＬ－２Ｒａ链ｍＲＮＡ转录，并降低膜表面ＩＬ－２Ｒａ链ｍＲＮＡ转录，并降低膜表面ＩＬ－２Ｒａ链的表达和细胞培养上清中可溶性ＩＬ－２Ｒ（ｓＩＬ－２Ｒ）水平。     

Epstein—Barr病毒膜抗原在昆虫细胞sf9中的表达,纯 …

将Ｅｐｓｔｅｉｎ－Ｂａｒｒ（ＥＢ）病毒膜抗原基因（ＥＢＶ－ＭＡ）称ＭＡ１和截去穿膜区的ＭＡ基因称ＭＡ２分别插入杆状病毒表达载体ｐＶＬ－９４１。将两种重组质粒分别与杆状病毒ＤＮＡ共转染ｓｆ９细胞后获得Ｂａｃｕｌｏ－ＭＡ１和Ｂａｃｕｌｏ－ＭＡ２两种重组病毒，表达产物分别位于重组病毒感染的细胞表面或释放到细胞培养液中。免疫荧光方法检查，在感染的细胞表面表达产物与抗ＭＡ的单克隆抗体特异性地结合，ＳＤＳ－Ｐ     

Expression of hMSH2 protein of the human DNA mismatch repair system in oral lichen planus

Lichen planus is a mucocutaneous disease of inflammatory nature and unknown etiology. It is characterized by a cell-mediated immunological response to induced antigenic change in skin and/or mucosa. The possible malignant transformation of lichen planus remains a subject of controversial discussions in the literature. hMSH2 is one of the human DNA mismatch repair (hMMR) genes and it plays an important role in reducing mutation and maintaining genomic stability. hMSH2 alterations have been reported in oral squamous cell carcinoma and there are evidences suggesting the association between oral lichen planus and squamous cell carcinoma. In this study, we aim to investigate the immunolocalization of hMSH2 protein in oral lichen planus compared to oral normal mucosa epithelium. We examined the expression of hMSH2 protein by immunohistochemistry in twenty-six cases of oral lichen planus. Clinically, 12 of them were categorized into reticular subtype and 14 were atrophic/erosive. Ten cases of normal mucosa were added to the control group. Results showed that the percentage of positive cells to hMSH2 was smaller in reticular (46.54%; p=0,006) and atrophic/erosive (48.79%; p=0,028) subtypes of oral lichen planus compared to normal mucosa (61.29%). The reduced expression of hMSH2 protein in oral lichen planus suggests that this lesion is more susceptible to mutation and therefore facilitate the development of oral squamous cell carcinoma.     

维甲酸和茶多酚对结肠癌细胞微卫星序列不稳定的抑制作用

目的 以复制错误（replication error,RER^ )表型的人结肠癌细胞株RKO作为靶细胞，研究全反式维甲酸（all-trans-retinoic acid,ATRA)和茶多酚（polyphenon,PP)对肿瘤细胞微卫星序列（microsatellite sequence,MS)突变的影响，并观察肿瘤细胞内碱基错误误配对修复（mismatch repair,MMR)基因hMLH1和hMSH2的表达情况。方法 将含有外源性MS（CA）14的穿梭质粒pCMV-CAR转染RER^ 人结肠癌细胞株RKO。外源性的（CA）14的突变可使质粒标记基因Lac Z恢复正常读码，表达产生β－半乳糖苷酶，后者使X－gal变蓝。全反式维甲酸和茶多酚对MS的影响可直接通过X－gal染色结果判断。利用逆转录－聚合酶链反应方法，检测经全反式维甲酸和茶多酚处理的RKO细胞中碱基错误配对修复基因hMLH1和hMSH2的表达情况。结果 全反式维甲酸1μmol/L、0．1μmol/L，茶多酚3μg/ml，对RKO细胞的增殖无明显的影响。作用1周后，均显示对外源性（CA）14的突变有明显的抑制效应。但不能诱导hMLH1和hMSH2表达。结论 全反式维甲酸和茶多酚能抑制RER^ 细胞中外源性（CA）14重复序列突变，提示两者对人癌细胞MS遗传不稳定有保护作用。其作用机理可能不是通过影响hMLH1和hMSH2的表达而起作用。     

Alterations of DNA mismatch repair proteins and microsatellite instability levels in gastric cancer cell lines

Alterations in DNA mismatch repair (MMR) proteins result in microsatellite instability (MSI), increased mutation accumulation at target genes and cancer development. About one-third of gastric cancers display high-level microsatellite instability (MSI-High) and low-level microsatellite instability (MSI-Low) is frequently detected. To determine whether variations in the levels of MMR proteins or mutations in the main DNA MMR genes are associated with MSI-Low and MSI-High in gastric cancer cell lines, the MSI status (MSI-High, MSI-Low or MS-Stable (MSS)) of 14 gastric cancer lines was determined using multiple clone analysis with a panel of five microsatellite markers. Protein levels of hMLH1, hMSH2, hMSH6, hPMS2 and hPMS1 were determined by Western blot. Sequence analysis of hMLH1 and hMSH2 was performed and the methylation status of the hMLH1 promoter was examined. The cell lines SNU1 and SNU638 showed MSI-High, decreased to essentially absent hMLH1 and hPMS2 and reduced hPMS1 and hMSH6 protein levels. The hMLH1 promoter region was hypermethylated in SNU638 cells. The MKN28, MKN87, KATOIII and SNU601 cell lines showed MSI-Low. The MMR protein levels of cells with MSI-Low status was similar to the levels detected in MSS cells. A marked decrease in the expression levels of MutL MMR proteins (hMLH1, hPMS2 and hPMS1) is associated with high levels of MSI mutations in gastric cancer cells. Gastric cancer cell lines with MSI-Low status do not show significant changes in the levels of the main DNA MMR proteins or mutations in the DNA mismatch repair genes hMSH2 and hMLH1. These well-characterized gastric cancer cell lines are a valuable resource to further our understanding of DNA MMR deficiency in cancer development, progression and prognosis.     

人MutS同源蛋白2(hMSH2)过表达的肺癌细胞模型的构建

目的构建人Mut S同源蛋白2(h MSH2)过表达的肺癌细胞模型,探究h MSH2分子介导γδT细胞杀伤肺癌细胞的效应。方法 PCR扩增h MSH2编码序列,同源重组法构建h MSH2-EGFP融合蛋白过表达载体;转染肺癌细胞系NCI-H520细胞以构建h MSH2分子过表达的NCI-H520细胞模型;Western blot检测细胞中h MSH2分子表达,流式细胞计量术检测细胞膜上h MSH2分子表达,体外扩增人外周血单个核细胞中的γδT细胞,乳酸脱氢酶释放法检测γδT细胞对过表达h MSH2的NCI-H520细胞的杀伤效率。结果获得h MSH2编码序列(2 805 bp),构建Fugw-h MSH2重组载体,酶切鉴定结果与预期目的条带大小相符;h MSH2-EGFP融合蛋白在NCI-H520细胞中得到表达,过表达h MSH2的NCI-H520细胞表面的h MSH2分子水平显著升高(P0.001);γδT细胞对过表达h MSH2的NCI-H520细胞的杀伤效率较野生型NCI-H520细胞显著升高(P0.05)。结论成功构建h MSH2分子过表达的肺癌细胞模型;细胞膜上表达水平上调的h MSH2分子增强了γδT细胞对肺癌细胞的细胞毒作用。     

Germline hMLH1 promoter mutation in a Newfoundland HNPCC kindred

Hereditary non-polyposis colon cancer (HNPCC) is an autosomal dominant form of inherited predisposition to colorectal and other malignancies. It is associated with mutations in DNA mismatch-repair genes, especially hMSH2 and hMLH1. Management of HNPCC families is improved if the underlying mutation in each family can be discovered. We describe a Newfoundland kindred, meeting the Amsterdam Criteria for HNPCC, in which a mutation in the promoter region of the hMLH1 gene co-segregates with the disease phenotype. The -42C > T mutation is within a putative Myb proto-oncogene binding site. Using electrophoretic mobility shift assays, we demonstrated that the mutated Myb binding sequence is less effective in binding nuclear proteins than the wild-type promoter sequence. Using in vivo transfection experiments in HeLa cells, we further demonstrated that the mutated promoter has only 37% of the activity of the wild-type promoter in driving the expression of a reporter gene. The average age of onset in six family members affected with colorectal cancer is 62 years, which is substantially later than the typical age of onset in HNPCC families. This is consistent with a substantial decrease, but not total elimination, of mismatch repair function in affected members of this family. This is the first report of a heritable hMLH1 promoter mutation in any HNPCC family.     

DNA错配修复基因甲基化在肝细胞癌发生发展中的作用

目的探讨DNA错配修复基因(MMR)hMLH1,hMSH2和hMSH3甲基化在肝细胞癌(HCC)发生发展中的作用。方法采用甲基化特异性聚合酶链反应(MSP)法对38例新鲜HCC组织,相应非肿瘤肝组织,2例正常的捐肝组织及6种肝癌细胞系的hMLH1,hMSH2和hMSH3基因启动子CpG岛甲基化进行检测;培养6种肝癌细胞系,MSP法检测加入5-aza-2‘-deoxycytidine前后hMSH2基因在HCC中的甲基化状态改变;逆转录．聚合酶链反应(RT-PCR)方法检测加入5-aza-2’-deoxycytidine前后hMSH2在肝癌细胞株中的mRNA表达改变。结果HCC标本中13．2％(5／38)发生了hMLH1启动子甲基化,68．4％(26／38)发生了hMSH2启动子甲基化;相应的非肿瘤肝组织中hMLH1,hMSH2启动子甲基化阳性率分别为2．6％(1／38),55．3％(21／38);2例正常肝组织中未发现甲基化;6株肝癌细胞系中有5株发生了hMSH2启动子甲基化,而未发现有MLH1启动子甲基化。所有标本中均未发现有hMSH3启动子甲基化。5-aza-2‘-deoxycytidine处理细胞株后,可部分或完全逆转hMSH2启动子甲基化,各细胞株的mRNA均有不同程度的表达增加。结论hMSH3基因启动子CpG岛甲基化与HCC的发生发展关系不大。hMSH2基因甲基化与mRNA表达密切相关,是基因表达调节的一种重要方式。hMLH1和hMSH2基因启动子CpG岛的高甲基化在HCC中是一个常见的基因改变,DNA错配修复基因尤其是hMSH2基因启动子甲基化在HCC的发生中起了重要作用,是早期事件,其可能为临床诊断HCC提供新的检测指标。     

hMSH3 and hMSH6 interact with PCNA and colocalize with it to replication foci

Proliferating cell nuclear antigen (PCNA) has been implicated in eukaryotic postreplicative mismatch correction, but the nature of its interaction with the repair machinery remained enigmatic. We now show that PCNA binds to the human mismatch binding factors hMutSalpha and hMutSbeta via their hMSH6 and hMSH3 subunits, respectively. The N-terminal domains of both proteins contain the highly conserved PCNA-binding motif Qxx[LI]xx[FF]. A variant of hMutSalpha, lacking this motif because of deletion of 77 N-terminal residues of the hMSH6 subunit, no longer was able to interact with PCNA in vitro and failed to restore mismatch repair in hMSH6-deficient cells. Colocalization of PCNA and hMSH6 or hMSH3 to replication foci implies an intimate link between replication and mismatch correction. We postulate that PCNA plays a role in repair initiation by guiding the mismatch repair proteins to free termini in the newly replicated DNA strands.     

Infection of HeLa cells by avian infectious bronchitis virus is dependent on cell status.

To investigate the adaptation of avian infectious bronchitis virus (IBV) in a human cell line may be beneficial to understanding the potential mechanisms of coronavirus interspecies infection. The current study addressed the poor replication of IBV in the HeLa human cell line demonstrated in previous reports. We showed that IBV strains M41, H52, H120 and Gray could be propagated in HeLa cells with distinct cytopathic effect. The virus titre in freshly dispersed HeLa cells was 1000-fold higher than in cell monolayers. Trypsin was not the determinant for the viral replication, suggesting that the restriction of IBV replication in HeLa cells is the result of intracellular events rather than the binding to or fusion with host cells. These IBV strains replicated to an average titre of 10(3.4+/-0.2)/0.1 ml median tissue culture infectious doses in freshly dispersed HeLa cells and maintained this titre for the first 12 passages. Then an approximately 10-fold increase (10(4.20+/-0.19)/0.1 ml) occurred in passage 13, which was maintained to passage 16, after which there was another, bigger rise to 10(6.6+/-0.3)/0.1 ml in passage 17. This titre was maintained until passage 24 when the experiment was terminated. The IBV M41 S1 gene was amplified and sequenced for passages 0, 5 and 21. There was only one amino acid replacement in the S1 protein, in passage 21. The presence of sialic acid on HeLa cells contributed to efficient virus replication, while human aminopeptidase N was not involved in the infection. Haemagglutinin activity gradually reduced with increased passages. These results indicated that the virus adaptation would probably be determined by host cell modification such as receptor glycosylation and different receptor utilization instead of viral gene mutation.