1．2倍基因组长度C基因型乙型肝炎病毒重组体构建及其在HepG2细胞中表达和复制

目的构建基于pBlueBac4．5质粒的1．2倍基因组长度C基因型乙型肝炎病毒（HBV）重组体，并研究其在HepG2细胞中的表达和复制。方法以重组质粒pWT上的1．2倍基因组长度C基因型HBVDNA序列和pBB4．5HBV1．3（D基因型）上的pBlueBac4．5载体序列为模板，构建重组质粒pBB4．5HBV1．2（C基因型）。用FuGENEHD瞬时转染法，将pBB4．5HBV1．2导人HepG2细胞。用化学发光免疫分析法、Southern印迹杂交法、荧光定量PCR法，分别检测转染后不同时间点HBsAg和HBeAg、HBV复制中间体及HBVDNA水平。此外，对转染时重组质粒用量进行优化。结果酶切和序列分析证实，pBB4．5HBV1．2重组质粒构建成功。初步转染实验证实，在转染细胞培养上清中可检测到HBsAg和HBeAg。优化后转染条件为：使用60mm细胞培养皿，8～11tLgpBB4．5HBV1．2，质粒与转染试剂5：9（μg：μl）。在此条件下，5d实验周期内可检测到HBsAg和HBeAg持续表达（峰值一般出现在转染后第3天）、HBVDNA持续复制（10^6～10^8拷贝／ml）及HBVDNA复制中间体形成。结论在HepG2细胞中，建立了以杆状病毒转移载体pBlueBac4．5为基础的1．2倍基因组长度C基因型HBV体外培养体系，有望为研究HBV耐药、筛选新抗病毒药物等提供新技术平台。     

替比夫定在预防肝移植后乙肝复发中的应用

目的评价替比夫定在预防肝移植后乙肝复发中的疗效及安全性。方法54例乙肝终末期肝病息者移植术后应用替比夫定及乙肝免疫球蛋白（HBIG）预防乙肝复发;6例移植术后应用拉米夫定出现病毒变异者停用拉米夫定,换用替比夫定＋阿德福韦。观察用药后HBVDNA复制、HBsAg以及HBeAg的变化及不良作用。结果54例患者[29例术前HBVDNA高复制（〉10^3 copies／ml）及25例低复制（〈10^3 copiea／ml）]在术后6个月时HBV DNA、HBsAg、HBeAg全部阴转;6例移植术后乙肝复发病例加用替比夫定3个月以上,5例乙肝标记物转阴。结论肝移植术前应用替比夫定,术后继续替比夫定治疗,可有效改善肝功能、抑制肝炎复发。     

青蒿琥酯对乙型肝炎病毒复制及肝癌细胞株HepG2.2.15凋亡的影响

目的 探讨青蒿琥酯在体外对乙型肝炎病毒复制及肝癌细胞株HepG2.2.15凋亡的影响.方法 将不同浓度青蒿琥酯作用于转染乙型肝炎病毒全基因组DNA的肝癌细胞株HepG2.2.15,收集48 h上清,采用酶联免疫吸附实验检测上清中乙型肝炎病毒表面抗原(HBsAg)和e抗原(HBeAg),采用荧光定量PCR法检测HBV-DNA,流式细胞术检测细胞凋亡.结果 青蒿琥酯对HBV复制具有抑制作用,随着浓度增加,对HBsAg和HBeAg的抑制率逐渐上升,细胞内HBV-DNA 复制水平下降;青蒿琥酯可诱导肝癌细胞早期凋亡及导致细胞死亡,随浓度增加,HepG2.2.15细胞早期凋亡率及死亡率均增加.结论 青蒿琥酯对HepG2.2.15细胞HBsAg和HBeAg的分泌及HBV-DNA复制具有抑制作用,并具有诱导HepG2.2.15细胞凋亡的作用.     

异戊烯焦磷酸刺激γδT细胞增殖及体外抗HBV作用

目的采用异戊烯焦磷酸(isopentenyl pyrophosphate,IPP)刺激人外周血单个核细胞(peripheral bloodmononuclear cells,PBMCs)中γδT细胞特异性增殖,观察其体外对HBV复制和表达的抑制作用。方法体外用IPP和rhIL-2刺激人PBMCs培养10天,流式细胞术检测培养前后γδT细胞含量;将γδT细胞与HepG2.2.15细胞按一定比例共孵育培养后,ELISA法测定上清中HBsAg,HBeAg的表达,荧光定量PCR检测HBVDNA的含量。结果采用IPP和rhIL-2刺激人PBMCs,可以使人外周血γδT细胞选择性激活和扩增,由4.34%±1.79%。增加至55.65%±6.88%。所扩增的γδT细胞,能够部分抑制HepG2.2.15细胞中HBVDNA复制和HBeAg的表达,对HB-sAg的表达没有明显抑制作用。结论采用IPP刺激PBMCs,能使γδT细胞选择性增殖,增殖的细胞能够降低HepG2.2.15细胞中HBV的复制和HBeAg表达,在乙型肝炎的过继性免疫治疗中具有潜在的临床应用价值。     

体内与转染细胞中乙型肝炎病毒株复制特性的相关性

目的 比较不同乙型肝炎病毒（HBV）株在体内及转染细胞中复制特性是否相符。方法 以核酸杂交定量和聚合酶链反应-酶联免疫吸附试验（PCR-ELISA）测定5例孕妇血清中HBVDNA含量,并测定乙型肝炎表面抗原（HBsAg)和乙型肝炎e抗原（HBeAg)含量,分别克隆血清中的HBV基因组转染细胞,检测培养上清液中HBsAg和HBeAg表达水平,并以Southern印迹及核酸杂交检测转染细胞内、外HBVDNA复制水平。结果 转染细胞内、外HBVDNA复制水平与相应血清HBVDNA量呈正相关趋势,转染细胞表达的病毒抗原水平与相应血清中病毒抗原含量也呈正相关趋势。结论 感染者血清中HBVDNA和病毒抗原的含量与毒株在细胞中复制和抗原表达水平有相符趋势。HBV不同毒株在转染细胞中的复制可基本反映体内毒株的复制特性。     

HBV临床分离株复制型质粒的构建与鉴定

目的克隆HBV临床分离株全长基因组,构建真核表达复制载体,为研究HBV的耐药机制提供基础。方法从乙型肝炎患者血清中提取HBV DNA,PCR扩增HBV全长基因组,经SapI酶切后,克隆入pHY106载体,测序分析序列,然后用lipofectamine 2000将重组载体转染Huh7细胞,3 d后收集培养上清液,ELISA检测HBsAg、HBeAg水平;Real-time PCR检测细胞培养上清液中HBV含量;Southern印迹检测细胞内HBV复制中间体。结果获得5株HBV临床分离株均为野生型,其中基因B型3株,基因C型2株。成功构建5株HBV临床分离株的复制型质粒,在转染Huh7细胞的上清液中检测到HBsAg、HBeAg及HBV DNA,细胞内检测到HBV复制中间体。结论成功克隆并构建了HBV临床分离株复制型质粒,这种复制型质粒将在HBV临床分离株的耐药机制和药物敏感性等方面研究中发挥重要作用。     

环孢素A对乙型肝炎病毒作用的体外实验

目的探讨环孢素A（CsA）在体外对乙型肝炎病毒（HBV）蛋白合成、DNA复制的影响。方法将不同浓度的CsA（0．6～20．0μg／ml）作用于HepG2．2．15细胞系，通过检测细胞培养上清液中乙型肝炎表面抗原（HBsAg）和乙型肝炎e抗原（HBeAg）水平；以及细胞内乙型肝炎核心抗原（HBcAg）mRNA水平和HBVDNA水平来评价HBV复制情况；通过检测细胞内PyK2激酶402位点酪氨酸（PyK2Y402）磷酸化水平来探讨CsA对HBV复制的作用机制。结果CsA对HBV复制具有抑制作用，随着CsA浓度的升高，对HBsAg和HBeAg的抑制率逐渐上升，细胞内HBVDNA复制水平下降。10．0μg／ml CsA作用4d时，对HBsAg和HBeAg的抑制率分别为49．7％和34．3％，HBVDNA的表达量仅为对照组的34．9％。在2．0“g／ml CsA作用下PyK2 Y402的磷酸化水平下降。结论CsA对HepG2．2．15细胞HBsAg和HBeAg表达、HBVDNA复制均有抑制作用，并呈剂量依赖性。CsA可能通过降低PyK2 Y402的磷酸化水平抑制HBV的复制。     

核苷的亲脂性磷酸酰胺酯β-LPA体外抗乙型肝炎病毒的作用

目的:探讨β-LPA体外抗乙型肝炎病毒(hepatitis B virus,HBV)的作用. 方法:通过β-LPA干预培养HepG2.2.2.15细胞,ELISA法检测上清HBsAg和HBeAg,32p标记HBV DNA为探针,Southern blot法检测细 胞内的HBV DNA,再以计算机图像处理进行定量分析,得出50%抑制的药物浓度(ED50),以MTT法检测不同浓度药物的细胞毒性,求出50%细胞抑制的药物浓度(ID50).结果:β-LPA体外明显抑制HBV DNA的复制,并呈浓度依赖性.ED50为0.01 μmol/L,β-LPA 细胞毒性实验显示ID50为50 μmol/L.低浓度的β-LPA对上清HBsAg,HBeAg无明显影响,高浓度时有显著的抑制作用.结论:β-LPA具有明显的体外抑制病毒DNA复制作用,且细胞毒性小.     

不同修饰的左氧氟沙星体外抗乙型肝炎病毒的作用及其作用机理的研究

目的本文用2.2.15细胞研究不同修饰的左氧氟沙星(磺酸左氧氟沙星、左氧氟沙星、乳酸左氧氟沙星)体外抗乙型肝炎病毒的作用及其作用机理。方法以HBsAg、HBeAg及细胞存活率为观察指标,综合评价不同修饰的左氧氟沙星体外抗HBV效果,进一步用荧光定量PCR方法测细胞内HBV DNA、HBV RNA及细胞上清HBV DNA的拷贝数,推测药物体外抗乙型肝炎病毒的作用机理。结果结果提示磺酸左氧氟沙星对HBsAg和HBeAg的ID_(50)分别为63.1μg/ml及81.3μg/ml,CD_(50)为182.0μg/ml,TI>2。磺酸左氧氟沙星对细胞内、外HBVDNA及细胞内HBV RNA均有明显的剂量依赖型抑制作用(P<0.05)。结论磺酸左氧氟沙星有明显的抗HBV作用,对HBV抑制位点可能在HBV DNA水平。     

乙型肝炎病毒表达载体pHY106在筛选抗病毒药物中的意义

目的应用新的HBV表达载体,建立体外筛选临床抗HBV药物的方法。方法克隆对拉米夫定耐药的CHB患者体内HBV全基因组,然后将其亚克隆到HBV真核表达载体pHY106,体外转染Huh7细胞,检测转染后不同时间HBsAg、HBeAg、HBV DNA及HBV复制中间体水平。分析拉米夫定和阿德福韦对HBV基因表达和复制的抑制作用,指导临床用药。结果成功构建全部8个HBV临床分离株全基因组真核表达质粒,HBV聚合酶基因YMDD有5个产生YVDD突变,3个产生YIDD突变。该质粒上HBV基因能在Huh7细胞中进行复制和表达,拉米夫定不能体外抑制HBV复制,阿德福韦抑制了HBV在Huh7细胞中的复制,抑制程度与药物浓度相关。阿德福韦在患者体内也抑制了HBV的复制。结论新建立的体外筛选抗HBV药物的方法能用于临床快速筛选抗HBV药物,对CHB的治疗用药具有指导意义。     

HBV感染性克隆长度对其复制能力的影响

目的比较不同长度HBV感染性克隆复制能力的差异,为HBV复制相关研究提供依据。方法采用分子克隆的方法体外分别扩增HBV基因组的相应片段,并进行连接,分别构建含1.1、1.2、1.3倍HBV基因组的可复制性克隆。体外转染Huh7细胞系评价抗原分泌和病毒复制情况,使用高压水注射建立急性感染小鼠模型评价病毒分泌情况以及抗原在小鼠肝脏内的表达情况。结果所构建的克隆体外转染Huh-7细胞后均可分泌高浓度的HBsAg,而1.3倍HBV基因组的可复制性克隆HBeAg的分泌能力明显强于其他克隆,转录水平也最高。高压尾静脉注射小鼠后肝组织内均可检测到HBcAg的分布,血清中可以检测到HBV DNA并随时间发生动态变化。其蛋白表达水平和病毒分泌能力均以1.3倍HBV基因组的可复制性克隆较高。结论所构建的克隆在体外及体内均可进行复制,其中含HBV全基因组1.3倍体的可复制性克隆的复制能力最强,可以较好反映来源病毒株的天然复制能力。     

Inhibition of hepatitis B virus replication by APOBEC3G in vitro and in vivo

AIM: To investigate the effect of APOBEC3G mediated antiviral activity against hepatitis B virus (HBV) in cell cultures and replication competent HBV vector-based mouse model. METHODS: The mammalian hepatoma cells Huh7 and HepG2 were cotransfected with various amounts of CMV-driven expression vector encoding APOBEC3G and replication competent 1.3 fold over-length HBV. Levels of HBsAg and HBeAg in the media of the transfected cells were determined by ELISA. The expression of HBcAg in transfected cells was detected by western blot. HBV DNA and RNA from intracellular core particles were examined by Northern and Southern blot analyses. To assess activity of the APOBEC3G in vivo, an HBV vector-based model was used in which APOBEC3G and the HBV vector were co-delivered via high-volume tail vein injection. Levels of HBsAg and HBV DNA in the sera of mice as well as HBV core-associated RNA in the liver of mice were determined by ELISA and quantitative PCR analysis respectively. RESULTS: There was a dose dependent decrease in the levels of intracellular core-associated HBV DNA and extracellular production of HBsAg and HBeAg. The levels of intracellular core-associated viral RNA also decreased, but the expression of HBcAg in transfected cells showed almost no change. Consistent with In vitro results, levels of HBsAg in the sera of mice were dramatically decreased. More than 1.5 log 10 decrease in levels of serum HBV DNA and liver HBV RNA were observed in the APOBEC3G-treated groups compared with the control groups. CONCLUSION: These findings indicate that APOBEC3G could suppress HBV replication and antigen expression both in vivo and in vitro, promising an advance in treatment of HBV infection.     

1.3倍乙型肝炎病毒全基因真核表达载体的构建及在HepG2细胞中的表达

目的 构建1.3倍全基因乙型肝炎病毒(HBV)真核细胞表达载体,观察其在HepG2细胞中的表达。方法 从pGEM—HBV载体上将约4.1kb的1.3倍HBV全基因克隆至真核表达载体pCDNA3.1的Hind Ⅲ位点,将构建的pHBV经Lipofectamine2000导入肝癌细胞系HepG2细胞中。分别在转染后24、48、72h测定HepG2上清液乙型肝炎表面抗原(HBsAg)、乙型肝炎e抗原(HBeAg)的表达,细胞内HBsAg、乙型肝炎核心抗原(HBcAg)免疫组织化学染色,Southern、northern杂交鉴定HBV的复制与表达。结果成功构建了1.3倍HBV全基因真核表达载体,转染后24、48、72h细胞上清液中HBsAg分别为5.36±0.25,13.42±1.24,7.52±0.43;HBeAg分别为9.16±0.32,22.75±1.49,15.96±1.03。免疫荧光结果显示转染后24 h细胞内HBsAg表达最强,主要呈胞浆内弥漫性分布,HBcAg为核浆型分布,以浆型为主。Southern、northern杂交均证实细胞内存在各种病毒复制中间体和特异的病毒复制转录物。结论 该表达载体可介导高水平病毒复制,其转染细胞可望成为一种新型的HBV 体外感染模型。     

Expression of hepatitis B virus 1.3-fold genome plasmid in an SV40 T-antigen-immortalized mouse hepatic cell line

AIM:To investigate the expression of the hepatitis B virus(HBV)1.3-fold genome plasmid(pHBV1.3)in an immortalized mouse hepatic cell line induced by SV40T-antigen(SV40T)expression.METHODS:Mouse hepatic cells were isolated from mouse liver tissue fragments from 3-5 d old Kunming mice by the direct collagenase digestion method and cultured in vitro.The pRSV-T plasmid was transfected into mouse hepatic cells to establish an SV40LT-immortalized mouse hepatic cell line.The SV40LT-immortalized mouse hepatic cells were identified and transfected with the pHBV1.3 plasmid.The levels of hepatitis B surface antigen(HBsAg)and hepatitis B e antigen(HBeAg)in the supernatant were determined by an electrochemiluminescence immunoassay at 24,48,72 and 96 h after transfection.The expressions of HBsAg and hepatitis B c antigen(HBcAg)in the cells were investigated by indirect immunofluorescence analysis.The presence of HBV DNA replication intermediates in the transfected cells and viral particles in the supernatant of the transfected cell cultures was monitored using the Southern hybridization assay and transmission electronic microscopy,respectively.RESULTS:The pRSV-T plasmid was used to immortalize mouse hepatocytes and an SV40LT-immortalized mouse hepatic cell line was successfully established.SV40LT-immortalized mouse hepatic cells have the same morphology and growth characteristics as primary mouse hepatic cells can be subcultured and produce albumin and cytokeratin-18 in vitro.Immortalized mouse hepatic cells did not show the characteristics of tumor cells,as alpha-fetoprotein levels were comparable(0.58±0.37 vs 0.61±0.31,P=0.37).SV40LTimmortalized mouse hepatic cells were then transfected with the pHBV1.3 plasmid,and it was found that the HBV genome replicated in SV40LT-immortalized mouse hepatic cells.The levels of HBsAg and HBeAg continuously increased in the supernatant after the transfection of pHBV1.3,and began to decrease 72 h after transfection.The expressions of HBsAg and HBcAg were observed in the pHBV1.3-transfect     

乙型肝炎病毒B和C基因型全基因组的克隆与真核细胞表达

目的 构建B和C基因型重组HBV表达载体,检测其在Huh7细胞内的DNA复制和HBsAg、HBeAg的表达.方法 扩增B和C基因型HBV全基因组,并将其连接于真核表达载体pHY106,将这2个载体分别转染Huh7细胞,以pHY106空载体转染作对照.Southern印迹法检测转染72 h后HBV DNA的复制,实时定量PCR检测转染后24、48、72、96和120 h Huh7细胞内HBV DNA水平,ELISA检测转染后24、48、72、96和120 h细胞培养上清液中HBsAg和HBeAg的表达.结果 成功构建了B和C基因型HBV表达载体.转染Huh7细胞后72 h,Southern印迹法检测到细胞内HBV核心颗粒内的HBV复制中间体,包括松弛环状DNA、双链DNA和单链DNA.实时定量PCR检测发现病毒DNA复制水平可达8 lg拷贝/mL、ELISA结果显示HBsAg和HBeAg的表达于转染后72 h达高峰,然后逐渐下降.结论 成功构建B和C基因型重组HBV真核表达载体,并能在Huh7细胞内高水平复制和表达,为进一步研究HBV的结构与功能、基因表达与调控,以及抗HBV药物的筛选等提供了良好的平台.     

Replication of clinical hepatitis B virus isolate and its application for selecting antiviral agents for chronic hepatitis B patients

AIM： To establish a cell model harboring replicative clinical hepatitis B virus （HBV） isolates and evaluate its application in individualized selection of anti-HBV agents for chronic hepatitis B （CHB） patients.
METHODS： The full-length HBV genomic DNA from 8 CHB patients was amplified by polymerase chain reaction （PCR）. All the patients were treated with lamivudine for at least seven months and finally became resistant to lamivudine. The amplified HBV DNA fragments were inserted into pHY106 vectors by Sap Ⅰ digestion. The recombinant plasmids containing 1.1 copies of HBV genome were transiently transfected into Huh7 cell line, and the levels of HBsAg, HBeAg and intercellular HBV replicative intermediates were determined by ELISA and Southern blot analysis, respectively, with or without lamivudine and adefovir treatment. The antiviral treatment with adefovir was administered to the patients and analyzed in parallel.
RESULTS： A total of 25 independent HBV isolates were obtained from the sera of 8 patients, each patient had at least two isolates. One isolate from each individual was selected and subcloned into pHY106 vector, including 5 isolates with YVDD mutation and 3 isolates with YIDD mutation. All recombinant plasmids harboring HBV isolates were transfected into Huh7 cells. The results indicated that HBV genome carried in HBV replicons of clinical HBV isolates could effectively replicate and express in Huh7 cells. Adefovir, but not lamivudine, inhibited HBV replication both in vitro and in vivo, and in vitro inhibition was dose-dependent.
CONCLUSION： The novel method described herein enables individualized selection of anti-HBV agents in clinic and is useful in future studies of antiviral therapy for CHB.     

Replication of hepatitis B virus in primary duck hepatocytes transfected with linear viral DNA

AIM: To explore the expression and replication of hepatitis B virus (HBV) DNA in primary duck hepatocytes (PDHs). METHODS: Complete HBV genome was transfected into PDHs by electroporation (transfected group, 1.19×1012 copies of linear HBV DNA/1×107 PDHs). After 1-5 d of transfection, HBsAg and HBeAg in the supernatant and lysate of PDHs were measured with the IMX System. Meanwhile, replicative intermediates of HBV DNA were analyzed by Southern blotting and Dot blotting. PDHs electroporated were used as control group. RESULTS: HBsAg in the hepatocyte lysates of transfected group was 15.24 (1 d), 14.55 (3 d) and 5.13 (5 d; P/N values, positive≥2.1) respectively. HBeAg was negative (<2.1). Both HBsAg and HBeAg were negative in the supernatant of transfected group. Dot blotting revealed that HBV DNA was strongly positive in the transfected group and negative in the control group. Southern blot analysis of intracellular total DNA indicated that there were relaxed circular (rc DNA), covalently closed circular (ccc DNA), and single-stranded (ss DNA) HBV DNA replicative intermediates in the transfected group, there was no integrated HBV DNA in the cellular genome. These parameters were negative in control group. CONCLUSION: Expression and replication of HBV genes can occur in hepatocytes from non-mammalian species. HBV replication has no critical species-specificity, and yet hepatic-specific regulating factors in hepatocytes may be essential for viral replication.     

N-terminal and C-terminal cytosine deaminase domain of APOBEC3G inhibit hepatitis B virus replication

INTRODUCTION Hepatitis B virus (HBV) infects more than 350 million people worldwide and is a leading cause of end-stage liver disease and of hepatocellular carcinoma[1]. HBV is non- cytopathic for hepatocytes; however, most newly HBV-infected adult patien…