中国登革2型病毒分离株乳鼠致病性差异与基因变化关系的研究

本文报道１９８７年从广西病人血清中分离的登革２型（Ｄ２）病毒Ｄ２－４３株和１９８５年从海南病人血清中分离的Ｄ２－０４株乳鼠致病性的差异与基因变化的关系。结果表明Ｄ２－４３株对乳鼠致病，Ｄ２－０４株不致病。Ｄ２－４３株和Ｄ２－０４株Ｃ到ＮＳ１基因的读码框架基本相同，均由３３８１核苷酸组成，编码氨基酸总数１１２７。包含三个结构蛋白Ｃ．ＰｒＭ（Ｍ）、Ｅ和一个非结构蛋白ＮＳ１。该两株病毒核苷酸序列同源性为９３．８％，氨基酸序列的类似性为９１．３％。Ｃ和Ｅ基因同源性为９５．０％～９５．８％，ＮＳ１基因为９２．２％，Ｍ基因为８６．７％，两株之间核苷酸序列的主要差异是在Ｍ基因。两株病毒的Ｃ－ＮＳ１基因与国际参考毒株比较，４３株与ＪＡＭ株类侧性最高，其次是ＮＧＣ株，与Ｓ１株类似性最小。而０４株只有Ｃ、Ｅ和ＮＳ１与ＪＡＭ株最高，ＰｒＭ（Ｍ）都与ＮＧＣ株最高。４３株与０４株的Ｍ基因相比较，０４株的ＰｒＭ（Ｍ）基因的同源性低于４３株，说明两株与国际参考毒株比较，主要差异也在Ｍ基因，乳鼠致病性差异可能与Ｍ基因变化有关。     

我国登革2型病毒43株非结构蛋白NS1基因的特征

对我国１９８７年从广西分离的登革２型病毒４３株非结构蛋白ＮＳ１基因的核苷酸序列进行了分析，结果表明登革２型病毒４３株非结构蛋白ＮＳ１基因含有１０５６核苷酸编码３５２个氨基酸，并就其核苷酸序列及其相应的氨基酸序列与我国１９８５年海南流行高峰期分离的Ｄ２－０４株、国际参考株新几内亚Ｃ株（ＮＧＣ）、牙买加株（ＪＡＭ）、候选疫苗株（Ｓ１）和马来西亚流行株Ｍ１（登革出血热）、Ｍ２（登革休克综合征）、Ｍ３（登革热）进行比较，发现核苷酸序列的同源性分别为９２．２％，９３．７％，９３．３％，９０．７％，８９．９％，８９．５％，８９．３％，氨基酸的类似性分别为８９．８％，９２．６％，９３．３％，９１．２％，９０．６％，９０．１％，８９；９％，推断的氨基酸序列含有两个糖基化位点，分别位于氨基酸残基的１３０和２０７位，一个可能的蛋白裂解位点３５０～３５２和１０个保守的半胱氨酸残基。     

丙型肝炎病毒E2／NS1区基因cDNA的克隆及序列分析

从北京地区１份丙型肝炎病毒（ＨＣＶ）感染者血清中提取ＲＮＡ，经逆转录和套式聚合酶链反应扩增ＨＣＶＥ２／ＮＳ１区基因约９３０ｂｐ，将其插入至ｐＧＥＭ－Ｔ质粒载体中，利用双脱氧链末端终止法测出该基因５’端４３１ｂｐ的核苷酸序列，将此序列与其它９个ＨＣＶ分离株的相应序列进行比较分析，结果表明，此序列与ＨＣＶⅡ型序列同源性较高，核苷酸水平同源性在８０％以上。由其编码的ＨＣＶ外膜蛋白Ｎ端存在两个高变部位（ＨＶＲ），在ＨＶＲ内、外具有几个保守氨基酸残基和氨基酸区域，它们与外膜蛋白空间构型的维持有关。     

登革2型病毒43株膜蛋白前体基因片段的克隆与表达

依照国际标准株ＮＧＣ的序列，设计合成了一对引物，用于扩增登革２型病毒中国分离株Ｄ２－４３的ＰｒＭＣ端抗原区的基因片段，结构分析及特异性分析的结果表明引物合乎要求，反转录（ＲＴ）－ＰＣＲ扩增出一３８５ｂｐ的目的片段，经ＨａｅⅢ酶切得到２１９、１６６ｂｐ的两条预期片段，表明ＲＴ－ＰＣＲ扩增出ＰｒＭ基因片断。扩增产物经ＢａｍＨＩ酶切后插入经ＳｍａＩ、ＢａｍＨＩ双酶切的ｐＵＥｘ１中，转化ＭＣ１０６１菌，表达与β－半乳糖苷酶的融合蛋白，ＳＤＳ－ＰＡＧＥ结果表明有一约１３０ｋＤ的目的蛋白带，表达量占菌体总蛋白的３０％，Ｗｅｓｔｅｒｎｂｌｏｔ及ＥＬＩＳＡ结果表明表达产物能与Ｄｅｎｇｕｅ－２多抗血清结合，为ＰｒＭ的免疫学及生物学性质研究打下了基础。     

中国广西狂犬病毒野毒株（CGX89－1株）糖蛋白基因核酸序列测定和分析

本文报告了中国广西狂犬病毒野毒株（ＣＧＸ８９－１株）糖蛋白基因ｃＤＮＡ的核苷酸序列及其推导的氨基酸序列。ＣＧＸ８９－１株的糖蛋白基因从起始密码ＡＴＧ到终止密码ＴＡＡ共有１５７５个核苷酸残基，可编码形成５２４个氨基酸残基的多肽链，经修饰后形成具有５０５个氨基酸残基构成的狂犬病毒糖蛋白。ＣＧＸ８９－１株的糖蛋白基因和核苷酸组成分别为：Ａ占２７．１１％，Ｔ占２６．２９％，Ｃ占２１．９７％和Ｇ占２４．６３％。核苷酸序列和巴斯德株（ＰＶ株），国际标准攻击毒株（ＣＶＳ株），中国狂犬病毒疫苗株（３ａＧ株）相比，同源性分别为８４．１％，８３．１％和８４．５％。其推导的氨基酸序列和ＰＶ株、ＣＶＳ株和３ａＧ株相比其同源性分别为９２．４％，８９．７％和８９．５％。ＣＧＸ８９－１株也具有３个Ｎ－糖基化位点，分别位于第３７位、１５７位和３１９位的氨基酸残基上。糖蛋白的膜外区部分重要抗原位点和ＰＶ株、ＣＶＳ株及３ａＧ株具有较高的一致性。     

中国狂犬病固定毒aG株N,NS和M蛋白基因的核苷酸序列测定

报告了中国狂犬病固定毒ａＧ株核衣壳蛋白（Ｎ蛋白），核蛋白壳磷酸蛋白（ＮＳ蛋白，又称Ｍ１蛋白）和基质蛋白（Ｍ蛋白，又称Ｍ２蛋白）蛋白基因的核苷酸序列和氨基酸推导序列。各基因编码区的全长分别是：Ｎ基因１３５２，ＮＳ基因８９４和Ｍ基因６０９个核苷酸。ａＧ和ＣＶＳ株的Ｎ，ＮＳ和Ｍ基因的核苷酸序列都具有高的同源性，分别为９１．９５％，９０．２７％和９０．８０％。     

中国狂犬病固定毒aG株N,NS和M蛋白基因的核苷酸序…

报告了中国狂犬病固定毒ａＧ株核衣壳蛋白（Ｎ蛋白），核蛋白壳磷酸蛋白（ＮＳ蛋白，又称Ｍ１蛋白）和基质蛋白（Ｍ蛋白，又称Ｍ２蛋白）蛋白基因的核苷酸序列和氨基酸推导序列。各基因编码区的全长分别是：Ｎ基因１３５２，ＮＳ基因８９４和Ｍ基因６０９个核苷酸。ａＧ和ＣＶＳ株的Ｎ，ＮＳ的Ｍ基因的核苷酸序列都具有高的同源性，别为９１．９５％，９０．２７％和９０．８０％。     

丙型肝炎病毒（HCV）E2／NS1相对保守区多肽抗原在检？…

目的 研究（ＨＣＶ）Ｅ２／ＮＳ１相对保守区多肽抗原在检测抗－ＨＣＶ中的意义。方法 利用ＨＣＶＥ２／ＮＳ１基因编码的膜区糖蛋白合成Ｅ２／ＮＳ１相对保守区多肽抗原,建立酶免疫试验（ＥＩＡ）,对９６例ＨＣＶ感染者及４０例正常献血员进行ＨＣＶＥ２／ＮＳ１抗体的检测,同时平行检测ＨＣＶＲＮＡ肝炎为１３．５５％,慢性丙型肝炎为２５．０４％,无症状感染者为２．０８％;正常献血员中发现３例抗ＨＣＶＥ２／ＮＳ１抗体     

鼻咽癌细胞株SUNE1中EB病毒LMP1全基因克隆及部分序列的测定

目的　研究广东地区鼻咽癌（ＮＰＣ） 细胞株ＳＵＮＥ１ 中ＥＢ病毒ＬＭＰ１ 基因的结构特征。方法　利用聚合酶链反应从ＳＵＮＥ１ 细胞基因组中扩增ＬＭＰ１ 全长ＤＮＡ,并克隆到ｐｃＤＮＡ３ 载体中,采用Ｓａｎｇｅｒ 双脱氧末端终止法测定ＳＵＮＥ１ＬＭＰ１ ３ 个外显子及２ 个内含子覆盖的序列,并与病毒原型Ｂ９５８ＬＭＰ１ 进行比较分析。结果　克隆到ｐｃＤＮＡ３ 中的ＳＵＮＥ１ＬＭＰ１ 全基因长度为２－６ ｋｂ,测序长度为１３１２ ｂｐ,与Ｂ９５８ＬＭＰ１ 比较,核苷酸与氨基酸的同源性分别为９８－５ ％ 和９６ ％ ,核苷酸及氨基酸变异主要在第３ 外显子,但无Ｃ端３４３～３５２ 密码子３０ 个碱基的缺失,第１ 外显子上有ＸｈｏⅠ酶切位点的丢失。结论　广东地区ＮＰＣ细胞株ＳＵＮＥ１ 中,病毒ＬＭＰ１ 基因与原型株之间尽管致瘤性存在差异,但仍具有较高的同源性。提示ＮＰＣ细胞中ＬＭＰ１ 的致瘤特征可能并非由于ＬＭＰ１ 基因某些特定核苷酸突变所致     

丙型肝炎病毒基因组部分E2／NS1蛋白基因在大肠杆菌中的表达

在大肠杆菌中表达了丙型肝炎病毒基因组的部分Ｅ２／ＮＳ１蛋白（氨基酸３６４－５１２）。表达蛋白经ＳＤＳ－ＰＡＧＥ分析，主要表达带的分子量在～４３０００左右。表达蛋白用于检测已用Ｃ３３ｃ及Ｑ２２检测过的血清，发现Ｅ２ＮＳ１引抗体阳性率占Ｃ３３ｃ及Ｑ２２抗体阳性血清的２０％，尚没有发现单独Ｅ２／ＮＳ１抗体阳性的血清。     

Nucleotide and deduced amino acid sequences of genes encoding the structural and nonstructural NS1 proteins of a dengue-2 virus isolated in China

We have determined the nucleotide and encoded amino acid sequences of the capsid, membrane precursor, membrane, envelope, and nonstructural NS1 protein genes of a dengue-2 virus (D2-04) isolated from a patient in Hainan, China. The sequenced region contains a gene organization similar to that of other flaviviruses. The overall amino acid sequence similarity between D2-04 and other dengue-2 viruses is greater than 92%, whereas that between D2-04 and members of the other dengue serotypes is about 65%.The nucleotide sequence data reported in this paper have been deposited in the EMBL database under the following accession numbers: X 65239 for the capsid (C), X 65240 for the envelope (E), X 65241 for the nonstructural (NS1), and X 65242 for the premembrane/membrane (prM/M) protein genes.     

Retrospective study of Western blot profiles in immune sera of natural dengue virus infections

The Western blot (WB) assay was used to determine dengue virus antibodies present in human immune sera arising from recent primary and secondary dengue virus infections in Singapore. Cell lysates of dengue-2 virus-infected C6/36 and Vero cells were used. Antibodies directed against structural proteins of dengue-2 virus including envelope (E, gp60/50), capsid-premembrane (C-PrM, gp35), and premembrane (PrM, gp20) were detected, with antibody against envelope protein being most dominant. Similar WB profiles were detected in both primary and secondary dengue virus infections. The reactivity rate of antibodies to dengue-2 virus proteins was higher in infected Vero cell lysate than in infected C6/36 cell lysate, with the exception of antibodies to nonstructural proteins of NS1 and NS3, which were detected predominantly in infected C6/36 cell lysate. More than 75% of "normal" individuals (with no complaint of recent dengue virus infection) examined had low levels of dengue virus antibodies, but all presented with similar WB profiles as patients with recent dengue virus infections. This finding reflects a high seroprevalence of dengue virus infections and the long lasting nature of E, C-PrM, and PrM antibodies. Results from this study indicate that in natural dengue virus infections, native E, C-PrM, and PrM antigens of dengue virus are immunogenic and elicit long-lasting antibodies.     

Antibody responses of dengue fever patients to dengue 2 (New Guinea C strain) viral proteins

The present study was undertaken to investigate the antibody responses of dengue fever (DF) patients to specific dengue virus proteins. Partially purified dengue 2 New Guinea C (NGC) strain virus was used as antigen. Under the present experimental protocols, it was observed that almost all DF patients' sera had detectable presence of antibodies which recognize the dengue 2 envelope (E) protein. The convalescent-phase sera especially had significant detectable IgG, IgM and IgE against the protein. In addition, IgGs specific against the NS1 dimer and PrM were also detected. Antibody against the core (C) protein, however, was not detectable in any of the DF patients' sera. The substantial presence of IgG against the PrM in the convalescent-phase sera, and the presence of IgE specific for the E, reflect the potential importance of these antibody responses in the pathogenesis of dengue.     

Nucleotide sequence and deduced amino acid sequence of the structural proteins of dengue type 2 virus, Jamaica genotype

The nucleotide sequence of the 5'-terminal 2469 bases of dengue 2 (Jamaica genotype) virus has been determined and the encoded proteins compared with those of yellow fever and West Nile viruses, which belong to different flavivirus serogroups. The cDNA clone which was sequenced contains a 5'-noncoding region of 96 nucleotides followed by a single open reading frame coding for the structural proteins 5'-C-prM(M)-E-3' and the beginning of the NS1 nonstructural protein. The amino acid sequence homology between the structural polyprotein precursor of dengue 2 virus and those of yellow fever and West Nile viruses is 36.5 and 42%, respectively. The dengue virus structural proteins are similar in size and composition to those of the other flaviviruses. The basic capsid protein and the membrane and envelope proteins have hydrophobic regions at their C termini. The dengue 2 capsid C, membrane M, and envelope E proteins share 13, 36, and 43% homology, respectively, with the cognate proteins of yellow fever virus, and 33, 32, and 47% homology with the cognate proteins of West Nile virus. All 6 cysteine residues in the dengue 2 premembrane protein and all 12 cysteine residues in the dengue 2 envelope protein are conserved in the cognate proteins of yellow fever and West Nile viruses.     

Evolution of attenuating mutations in dengue-2 strain S16803 PDK50 vaccine and comparison of growth kinetics with parent virus

A live-attenuated dengue-2 virus strain S16803 vaccine candidate that is immunogenic and safe in humans was derived by 50 passages in primary dog kidney (PDK) cells. To identify mutations associated with attenuation of the dengue-2 PDK50 vaccine strain, we determined the nucleotide changes that arose during PDK passage of the dengue-2 virus. Thirteen mutations distinguished the PDK50 virus from low-passage parent resulting in amino acid substitutions in the premembrane (E89G), envelope (E202K, N203D), nonstructural proteins NS1 (A43T), NS2A (L181F), NS2B (I26V), and NS4B (I/T108T, L112F). In addition, the PDK50 virus contained a C to T change of nucleotide 57 in the 5′ non-coding region and four silent mutations of nucleotides 591, 987, 6471, and 8907. An infectious PDK50 cDNA clone virus was produced and characterized for growth kinetics in monkey (LLC-MK₂, Vero) and mosquito (C6/36) cells. Identification of mutations in the vaccine strain and availability of an infectious clone will permit systematic analysis of the importance of individual or collective mutations on attenuation of dengue virus.     

登革2型病毒04株5‘和3’末端的序列分析

目的 观察登革２型病毒０４株（Ｄ２－０４）基因组５’和３’末端序列。方法 从Ｄ２－０４感染的Ｃ６／３６细胞中提取总ＲＮＡ,以该ＲＮＡ为模板,利用ＲＡＣＥ法,分别扩增Ｄ２－０４株的５’和３’末端ｃＤＮＡ片段。将其分别与ｐＧＥＭ－Ｔ载体连接得到含有５’端５３５ｂｐ和３’端５０３ｂｐ ｃＤＮＡ的重组质粒,并测定上述ｃＤＮＡ插入片段的序列。将Ｄ２－０４的５’和３’端非编码区的核苷酸序列与其它登芏２型毒株进     

Antigenic cell associated dengue 2 virus proteins detected in vitro using dengue fever patients sera

At least three major antigenic dengue 2 virus proteins were recognized by pooled dengue fever patients' sera in infected Aedes albopictus (C6/36) mosquito cells. Dengue virus envelope (E), premembrane (PrM) and non-structural protein 1 (NS 1) dimer were detected beginning on day 3 postinfection in both the cell membrane and cytosolic fractions. Using the patients' sera, the presence of antigenic intermediate core protein (C)-PrM and NS1-non-structural protein 2a (NS2a) in the cytoplasmic fraction of dengue 2 virus infected cells was revealed. The presence of a approximately 92 and approximately 84 kDa NS 1 dimer in the membrane (NS 1m) and cytosolic (NS 1c) fractions of C6/36 cells, respectively, was also recognized. Using individual patient's serum, it was further confirmed that all patients' sera contained antibodies that specifically recognized E, NS 1 and PrM present in the dengue 2 virus-infected cell membrane fractions, suggesting that these glycosylated virus proteins were the main antigenic proteins recognized in vivo. Detection of dengue 2 virus C antibody in some patients further suggested that C could be antigenic if presented in vivo.     

Comparative analysis of the NS 1 gene sequences of dengue-1 viruses prototype Hawaii strain and Thai isolate TH-Sman,and determination of the intratypic variation of NS 1 protein among dengue-1 viruses

Summary In view of a previous report on significant antigenic and biophysical differences between the purified soluble complement-fixing antigens of dengue-1 virus strains Hawaii and TH-Sman, the NS 1 genes of both virus isolates were cloned, sequenced, and compared in an attempt to define the genetic basis for the observed differences. Sequence comparison revealed ten encoded amino acid differences between the NS 1 genes of both viruses. Three of these amino acid differences, which are associated with a change in charge distribution, are clustered within the major antigenic region previously defined by studies of recombinant dengue-1 NS 1 protein expressed inE. coli. In parallel, the NS 1 sequences of both Hawaii and TH-Sman isolates were also aligned and compared with two other published dengue-1 NS 1 protein sequences to determine the intratypic variation of dengue-1 NS 1 antigen. Pairwise comparisons between the encoded amino acid sequences revealed a variability of 1.1% to 3.1% difference in the NS 1 protein among dengue-1 strains, which is comparable to that reported for dengue-1 envelope protein (0.2% to 3.6% difference) but less than that of dengue-2 NS 1 protein (0.6% to 7.4% difference).     

新分离登革2型病毒福建株基因组全序列的测定

目的 对新近分离的导致1999年福建省登热流行的登革2型病毒FJ－10株进行基因组全序列测定及系统发生树分析。方法 利用RT－PCR和5′、3′RACE法扩增FJ－10株cDNA,并进行克隆测序,利用DNASTAR折Clustal方法绘制系统发生树。结果 JF－10株基因组全长10723个核苷酸,有1个单一开放读码框架（ORF,第97－10269nt）,编码3391个氨基酸,5′和3′非编码区长度分别为96和454个核苷酸,通过与标准株NGC株和我国其他地区分离株DEN2－04、43、44株比较,核苷酸同源性分别为94.0%、92.8%、93.9%和93.9%,氨基酸同源性分别为97.9%、97.2%、97.7%和97.9%。以47株登革2型病毒E／NS1连接区240个核苷酸序列进行发生树分析,福建株与印度尼西亚和斯里兰卡分离株亲缘关系较近,同属第Ⅳ基因型。结论 FJ－10株基因组全序列一级结构与其他登革2型病毒类似,其基因型不同于我国其他地区分离株DEN2－04、43和44株。