丙型肝炎病毒NS4区多肽的抗原性研究及应用

为挑选NS4中的优势抗原表位用于丙型肝炎病毒(HCV)的血清学检测,对相应区段的多肽进行了细致分析,以选择合适的肽段进行研究。在以Goldkey软件分析NS4肽氨基酸序列的基础上,采用人工合成肽技术合成了3条多肽,分别含15,21和28个氨基酸残基(依次命名为P15P21和P28),并研究了各肽段的抗原性。通过DNA合成和基因工程技术,表达了选择的优势抗原决定簇。将其用于HCV阳性和阴性系列血清的检测,结果表明,根据上述研究构建的融合NS4多肽抗原的抗原性优于合成肽,可用于作为HCVEIA的试剂。     

HCV高变区合成多肽的抗原性研究

目的：通过计算机同源模建，寻找丙型肝炎病毒高变区（HCV HVR1）中保护性多肽抗原表位。方法：计算机同源模建，预测多肽的抗原性，然后用淋巴细胞转化的方法验证其抗原性，结果：同源模建与实验结果一致，多肽抗原性有待进一步的提高。结论：同源模建是一种高效寻找具有保护性抗原多肽的经济快速方法。     

鼠抗丙型肝炎病毒ns—5区单克隆抗体的研究

用ＨＣＶ非结构区ｎｓ－５合成多肽抗原交联后免疫小鼠，成功地建立了３株抗ｎｓ－５单克隆抗体（ＭｃＡｂ），经检测这３株ＭｃＡｂ属于同一位点，与其它区域无明显交叉反应，具有高度特异性。ＭｃＡｂ的研制为检测ｎｓ－５抗原奠定了一定基础。     

丙型肝炎病毒NS3区辅助性T细胞抗原表位的应答

观察２例慢性ＨＣＶ携带者及１例ＨＣＶＲＮＡ转阴者外周血淋巴细胞对ＨＣＶＮＳ３区辅助性Ｔ细胞抗原表位的应答。方法用血清学方法检测患者的ＨＬＡ分型。根据计算机软件分析和文献资料,合成了１个位于ＨＣＶＮＳ３区长度为１４个氨基酸的辅助性Ｔ细胞表位,与在ＧｅｎｅＢａｎｋ中已发表达的３４个ＨＣＶ全长序列进行了比较。     

丙型肝炎病毒不同基因型NS3蛋白的抗原异质性分析

目的探讨不同基因型丙型肝炎病毒(HCV)NS3蛋白的抗原特性及其用于抗-HCV检测的意义。方法分别构建和表达含有HCV1型和6型NS3基因片段的重组质粒和重组蛋白，以EIJSA法和Western blot分析不同基因型重组蛋白与已知抗-HCV阳性血清的抗原反应性。结果HCV1型和6型NS3重组蛋白氨基酸序列的同源性为83．2％；85份抗-HCV阳性血清以此不同基因型HCV NS3单片段抗原检测，阳性检出率分别为61．2％(1型)和58．8％(6型)，其中有7份标本以NS3-1型抗原检测阴性，但可被NS3-6型抗原检出，反之，有9份血清以NS3-6型重组蛋白检测为阴性，而NS3．1型检测阳性；54份大学生体检血清和39份阴性质控血清以此两种抗原检测均为阴性。结论HCV1型和6型NS3重组蛋白存在抗原异质性，在发展HCV抗体检测试剂时需考虑加入不同基因型的NS3抗原。     

肝细胞癌中丙型肝炎病毒NS3抗原和HBsAg的表达

肝细胞癌中丙型肝炎病毒ＮＳ３抗原和ＨＢｓＡｇ的表达汪荣泉周子成杨建民房殿春作者单位：６３００３８重庆第三军医大学西南医院消化科１９９６年９月１８日收稿１９９７年６月１７日修回原发性肝细胞癌（ＨＣＣ）是我国目前最常见的恶性肿瘤之一，血清学和分子流行病学...     

丙型肝炎病毒NS5ab区的B细胞模拟表位的确认

目的：用噬菌体展示随机肽库研究丙型肝炎病毒(HCV)NS5ab区的B细胞表位。方法：在原核系统中表达了HCV NS5ab重组蛋白，亲和层析纯化血清中抗HCV NS5ab的特异多抗，用此多抗来筛选噬菌体递呈随机12肽库，获得HCV NS5ab区的B细胞表位。结果：成功地表达了HCV NS5ab重组蛋白，用此蛋白检验了130份HCV阳性血清，阳性率为36％。在筛选的噬菌体展示随机肽库后，挑取13个阳性克隆测序，有9个序列不同，最终通过噬菌体表位表达的方法确认了3个表位。结论：筛选噬菌体展示随机肽库研究HCV的B细胞模拟表位是可行的。     

中国人庚型肝炎病毒E1区5‘端基因相关多肽的抗原性初步研究

用逆转录－ＤＮＡ聚合酶链反应从１例中国庚型肝炎患者血清中扩增出仿前区部分基因及Ｅ１区５‘端共３０９ｂｐ基因片段，对其中包括Ｅ１区９６ｂｐ在内的１２０ｂｐ核苷酸进行了序列分析，发现此区段基因与录入号为Ｕ４４４０２Ｇｅｎｅｂａｎｋ报道的美国发现的ＨＧＶ相关序列具有９３％的同源性。     

慢性丙型肝炎患者丙型肝炎病毒NS5A区序列与干扰素疗效的关系

目的　探讨上海地区丙型肝炎病毒 (HCV) 1b亚型慢性感染者的血清HCV非结构基因5A(NS5A)与干扰素 (IFN)疗效的关系。方法　收集上海地区 2 4例HCV1b慢性感染者在干扰素治疗前后及随访过程中的血清标本 ,定量检测治疗前血清HCVRNA ,用逆转录 聚合酶链反应方法扩增NS5A的干扰素敏感决定区 (ISDR)基因并进行测序和分析。另扩增干扰素应答类型不同的 3例患者治疗前后共 5株HCV病毒的NS5A全长序列 ,测序后作种系发生树分析及蛋白二级结构预测。结果　治疗前血清HCVRNA的定量结果显示 ,持续应答组的病毒滴度 (平均滴度 4 50× 1 0 4copies ml)明显低于复发组和无应答组 (平均滴度 1 82× 1 0 7copies ml)。 2 4例慢性丙型肝炎患者干扰素治疗前血清HCV的ISDR氨基酸序列与抗干扰素的HCV J株比较 ,1 3例为野生型 ,1 1例为中间型 ,无突变型。 6例完全应答者 3例感染的是野生型株 ,另 3例感染的是中间型病毒株。 5株HCV病毒的NS5A全长序列种系发生树显示 ,3种不同应答类型株在种系发生上分属 3个组别 ,无应答株与抗干扰素的HCV J株关系相近被归为 1组。蛋白质二级结构预测显示 ,上述病毒株NS5A蛋白在二级结构方面基本相似 ,仅在 2 2 55～ 2 2 89范围内有明显不同 ,这一区域与PKR结合域部分重叠。结论　HCVNS5A基因     

丙型肝炎高变区多肽的同源建模与抗原性研究

目的 通过计算机同源模建,寻找丙型肝炎变区中保护性多肽抗原表位。方法 用计算机同源建模预测多肽的抗原性,然后用淋巴细胞转化试验验证其抗原性。结果 同源建模与实验结果相一致。结论 同源模建是一种高效寻找具有保护性的抗原多肽的经济快速的方法。     

SiRNA对丙型肝炎病毒5''非翻译区的干扰作用实验研究

目的研究多种siRNA对丙型肝炎病毒（HCV）5’非翻译区（5＇-UTR）的干扰作用。方法以绿色荧光蛋白基因（GFP）为报告基因，构建HCV5’UTR与GFP核酸序列连接的表达载体：pcDNA—HCV-5’UTR—GFP。设计针对HCV5’UTR区3段小干扰RNA（siRNA），siRNA与表达质pcDNA—HCV-5’UTR—GFP共转染HepG2细胞中，采用荧光显微镜观测细胞内荧光强度改变，并且用流式细胞术量化分析细胞荧光强度变化，评价多种siRNA对HCV基因表达的作用。结果成功构建含HCV5’UTR区的绿色荧光蛋白基因，siRNA能特异性地抑制绿色荧光蛋白基因的表达，siRNAA、siRNAB和siRNAC的抑制率分别为68．4％、72．6％、75．6％；siRNA＋siRNAB、siRNB＋siRNAC和siRNA＋siRNAc的抑制率分别为91．8％、87．2％、92．4％；siRNA＋siRNAB＋siRNAC的抑制率最高，为95．7％。结论多种siRNA对HCV5’UTR区具有干扰作用，组合使用效果更好。     

庚型肝炎病毒NS5区优势抗原表位的表达及其抗原性的初步评价

目的 表达庚型肝炎病毒（HGV）基因且NS5区部分基因重组抗原，分析其抗原性。方法 分别亚克隆了HGV NS5a、NS5b以及NS5b与C区嵌和的基因至pThoiC表达载体上，构建成3个重组表达质粒，分别大肠埃希菌JM109（DE3），用IPTG诱导表达重组蛋白。表达产物经纯化后采用Western blot和间接ELISA方法分析3个重组蛋白的抗原性。结果 经酶切和序列分析鉴定正确，3种表达蛋白均高效表达且相对分子质量与预期大小相符。Western blot分析和间接ELISA试验表明，3种表达蛋白均能与抗－HGV阳性血清发生特异性反应。将应用重组蛋白检测的抗－HGV抗体与混合重组抗原（包括C区合成肽、NS5a合成肽、NS3区基因重组抗原）的检测结果进行了比较，在混合重组抗原阳性的22份血清中，P5a检出率为68％（15／22），P5b检出率为91％（20／22），Pc-5b检出率为73％（16／22）。在70份阴性标本中，3种抗原的检出率分别为P5a:7%(5/70);P5b:1%(1/70);Pc-5b:6%(4/70)。3个重组抗原单独检出阳性的标本，其中有一部分经RT－PCR检测亦为阳性。结论 原核表达的NS5区蛋白所检测的抗－HGV抗体不能完全被其他区段的抗原所覆盖，是免疫诊断HGV感染所必需的抗原表位之一。     

Localization and reactivity of an immunodominant domain in the NS3 region of hepatitis C virus

Analysis of the amino acid sequences of the non-structural region 3 (NS3) of the hepatitis C virus type 1 revealed four points with a high average hydrophilicity (Ah). Two of these potential anti-genie sites were expressed in E. coli as short fragments. The first fragment of 91 residues (NS3f3: residues 1359–1449) harbors the hexapeptide K-K-K-C-D-E with an Ah of 2.33; the second fragment is 73 residues long (NS3f4: residues 1460–1532) and encompasses the hep-tapeptide R-S-N-R-R-G-R with an Ah of 1.79. Both fragments were expressed with truncated hepatitis B core (tHBc) as a carrier protein. The fusion proteins were purified from the bacterial lysates by affinity chromatography on immobilized monoclonal antibodies against HBc, and evaluated as antigens in an enzyme immunoassay for the detection of HCV antibodies. In a specificity control panel, reactivity with NS3f3 was only found in proven HCV carriers, while reactivity with NS3f4 was weak in HCV carriers but accounted for some of the nonspecific serological reactions. In a group of 48 genotyped HCV-in-fected volunteer blood donors, antibodies against NS3f3 were detected in 90% (27/30) of HCV-type 1 infections and in all HCV-type 4 infections (5/5). However, in carriers infected with HCV-types 2, 3, or 5, the response rate was on average only 23% (3/13). With NS3f4 as antigen, weak antibody titers were found in only about half of the carriers, independent of the infectious genotype. In a cohort of hemodialysis patients, all infected with HCV-type 1b, NS3f3 antibodies were detected in 80% (16/20) of the carriers, while only one patient showed a weak NS3f4 reactivity. It is concluded that NS3f3 harbors an immunodominant domain of the NS3 region showing an apparently HCV-type-dependent serological response. © 1995 Wiley-Liss, Inc.     

2a型HCV E1、E2/NS1区基因cDNA的克隆及序列分析

目的：了解丙型肝炎病毒（HCV）2a型基因组E1 E2／NS1区序列，为进一步研究HCV包膜蛋白的生物学功能奠定基础。方法：用逆转录套式PCR（RT－nPCR)从江苏省1例丙型肝炎患者血清中扩增出两条分别约770bp、1100bp的片段，分别以限制性内切酶EcoR I、BamH I和EcoR I、Hand Ⅲ双酶切后连入pUC19载体中，转化感受态细胞，经限制性酶切长度多态性分析（RFLP）和PCR法证实为阳性克隆后，用全自动序列分析仪测序。结果：分别测得约770bp、1100bp的核苷酸序列，拼接后得到的完整核苷酸序列及其编码的氨基酸序列分别与HCV－1、HC－C2、HCV－BK、HC－J6、HC－J8相应序列作比较，显示分离株HCV在核苷酸水平上与以上分离株的同源性分别为60．5％、60．1％、59．7％、87．8％、67．5％；在氨基酸水平上的同源性分别为67．3％、66．4％、65．0％、87．8％、79．0％。结论：分离株（HCV－JS）与HC－J6同属2a型，但同源性有一定差异。     

Antigenic heterogeneity of the hepatitis C virus NS4 protein as modeled with synthetic peptides

The effect of sequence heterogeneity on the immunologic properties of two strong antigenic regions of the hepatitis C virus (HCV) NS4 protein was studied by using a set of 443 overlapping 20-mer synthetic peptides. One antigenic region comprising the cleavage site between NS4a and NS4b (region 5-1-1) was modeled with peptides derived from 73 different known sequences, representing HCV genotypes 1-6. The other antigenic region, designated region 59 and located at the C-terminus of the NS4b protein, was modeled with peptides from 7 known sequences representing genotypes 1-3. All peptides were tested for antigenic reactivity by enzyme immunoassay with a panel of anti-HCV-positive serum specimens representing genotypes 1-5. The data demonstrated that immunoreactive peptides fell into two groups. One group, represented by N-terminal peptides, demonstrated genotype-independent immunoreactivity; the other group, from the central part of region 5-1-1, showed strict genotype specificity. Nineteen peptides from the genotype-independent group strongly immunoreacted with a wide range of serum samples containing antibodies to all 5 HCV genotypes. Twenty-five peptides from the genotype-specific group were found to strongly react with serum containing antibodies only to the genotype from which the peptides were derived. Similar to the N-terminal part of region 5-1-1, peptides derived from region 59 did not show genotype-specific immunoreactivity. Some peptides derived from the central part of region 59 showed very strong and broad antigenic reactivity. Thus, after examining two antigenic regions of the NS4 protein, we identified short sequences that can be used for the efficient detection of either genotype-independent or genotype-specific HCV antibodies.     

The NS5a gene of hepatitis C virus in patients treated with interferon-alpha

Patients infected with hepatitis C virus (HCV) genotype 3 have a better response to interferon-alpha (IFN-alpha) therapy than those infected with genotype 1. There are extensive sequence differences between genotypes in the 3' half of the NS5a gene. An association between IFN-alpha response and the interferon sensitivity-determining region (ISDR) (amino acids 2209-2248) of HCV genotype 1b has been described [Enomoto et al. (1996) New England Journal of Medicine 334:771-776]. A prospective study was conducted to determine whether the derived NS5A amino acid sequence or quasi-species diversity could predict response to IFN-alpha therapy. Serum samples were obtained before, during, and after treatment from 35 IFN-alpha-treated patients chronically infected with HCV (eight with type1b,13 with type1a, and 14 with type3a). Nucleotide sequences were determined, and amino acid sequences corresponding to residues 2178-2390 of the polyprotein were derived. Quasi-species complexity was analysed by amplification of the ISDR region (2270-2403), followed by single-stranded conformation polymorphism (SSCP). No amino acid sequence that could be used to predict response to treatment was found, and there was no selection of specific amino acid residues during treatment. A striking lack of variability was seen in HCV genotype 3a, but the small degree of variation could suggest an effect on response. SSCP showed that variation in the predominant NS5a sequence occurred in the presence and absence of therapeutically administered IFN-alpha. HCV quasi-species diversity pretreatment did not predict IFN-alpha treatment outcome. The conclusion of the study is that the amino acid sequence of NS5a cannot be used to predict the efficacy of treatment with IFN-alpha in HCV-infected patients in Scotland. No evidence was found to support the selection of IFN-alpha-resistant strains in the NS5a gene.     

反义RNA体外抑制丙型肝炎病毒基因表达的研究

目的 研究丙型肝炎病毒(HCV)基因调控方式及反义RNA对HCV基因表达的体外抑制作用。方法 采用业已建立的HCV基因调控细胞模型，以重组质粒共转染策略，将反义RNA重组质粒与HCV5′非翻译区(5′UTR)调控的报道基因——虫荧光素酶(luc)重组质粒共同转染人肝癌细胞系(HepG2)，并以不表达反义RNA的原核重组质粒和不含有HCV5′UTR的luc重组质粒做为对照。转染细胞经短期培养后制备细胞提取液，荧光检测法检测luc基因的表达。结果 针对HCV5′uTR的反义RNA可以在体外有效抑制由HCV5′UTR调控的luc基因的表达，并具有剂量依赖效应。对照重组质粒转染实验证明，上述抑制作用呈序列特异性。结论 HCV5′UTR具有调控下游目的基因表达的重要功能，反义RNA可以在体外有效抑制由HCV5′UTR介导的病毒基因的表达。     

慢性丙型肝炎病毒患者表面蛋白多变区的变异

目的: 探讨慢性丙型肝炎患者HVR1核苷酸变异的频率。方法: 通过RT-PCR、LightCycler测序及序列分析对3例丙型肝炎病毒慢性感染患者进行核苷酸的动态分析。结果: 我们发现此3名患者多变区多处核苷酸出现不同程度的变异。结论: 慢性感染患者多变区核苷酸变异与免疫逃逸有关。