戊型肝炎病毒结构区基因的克隆表达及其在诊断中的初步应用

目的研制戊型肝炎病毒诊断试剂。方法利用融合蛋白表达载体ｐＧＥＸ－３Ｘ表达了戊型肝炎病毒第二读码框区（ＯＲＦ２４０２～６６０）优势抗原表位。表达抗原溶于水，可利用商品化的谷胱甘肽Ｓｅｐｈａｒｏｓｅ－４Ｂ亲合层析柱得到纯化的抗原。结果经应用发现，此基因重组抗原作为酶联免疫试剂的抗原，用于检测血清中抗戊型肝炎病毒抗体，与新加坡进口试剂盒有高度的一致性，和血清中抗体反应性更强。结论预示该基因抗原可能具有较好的反应谱，应用前景乐观     

戊型肝炎酶联免疫诊断方法的建立及其应用

用基因工程重组的戊型肝炎病毒抗原ＯＦＲ３，ＯＲＦ２和ＯＦＲ３－２嵌合抗原及化学合成的ＯＲＦ３多肽抗原，分别建立了酶联免疫方法，检测５５份临床可凝的戊型肝炎病人血清中ＨＥＶ抗体，以ＯＲＦ３－２嵌合抗原检测的抗体阳性率最高，为９４．５％，ＯＲＦ３重组抗原和多肽抗原检测的抗体阳性率分别为９３％和９１％，ＯＲＦ２抗原检测的抗体阳性率为４９％。     

合成肽作抗原酶免疫技术检测非甲—戊型肝炎病人血清中抗HGV

本文应用人工合成肽作为抗原建立了检测庚型肝炎病毒抗体的酶免疫技术，最适抗原包被浓度为４μｇ／ｍｌ。在特异性验证的基础上，检测了３４例非甲－戊５型肝炎病人血清和３２例丙型肝炎感染病人血清。     

用杆状病毒系统表达戊型肝炎病毒全长结构基因的研究

目的：获取含有戊型肝炎病毒（HEV）全长结构基因的重组杆状病毒，表达戊型肝炎病毒结构蛋白。方法：将HEV全长结构基因（5147－7126nt）插入杆状病毒表达载体pAcUW51，与线性化杆状病毒DNA（Baculo Gold DNA）共转染Sf9昆虫细胞，挑病毒斑进一步感染Sf9细胞，用SDS－PAGE，Western Blot及免疫荧光检测戊型肝炎病毒结构蛋白的表达及活性。结果：SDS－PAGE分析表明HEV结构基因在杆状病毒系统中高效表达，有相对分子质量约为73000和63000两种形式；Western Blot及免疫荧光检测证明表达产物可与HEV阳性血清特异反应，说明具有HEV特异抗原性。结论：应用杆状病毒表达系统成功表达了HEV结构蛋白。     

散发性戊型肝炎病毒感染的诊断

用基因工程重组的戊型肝炎病毒基因结构区第二码框架和第二读码框架具有免疫表位的嵌合抗原，建立了间接酶联免疫法，检测散发性急性肝炎病人血清中抗－ＨＥＶＩｇＧ和ＩｇＭ抗体。在４６例急性肝炎病人中出抗－ＨＥＶＩｇＧ抗体阳性７例，阳性率为１５．２２％，７例ＩｇＧ抗体阳性中，有５例ＩｇＭ抗体也阳性，占７１．４％。     

戊型肝炎病毒ORF2 C端抗原片段的表达及其免疫学特性研究

目的　表达戊型肝炎病毒 (hepatitisEvirus ,HEV)ORF2C端 12 8个氨基酸残基的抗原片段ORF2 3 ,并进行其免疫学特性的研究。方法　用pBV2 2 0载体进行抗原的非融合表达 ,包涵体经变性凝胶过滤层析及离子交换层析纯化后透析复性 ,以Westernblot、ELISA、动物免疫与抗原捕获RT nPCR等方法研究其免疫学特性。结果　获得了ORF2 3的高效表达 ,表达量占菌体总蛋白 5 0 %左右 ,纯化后纯度达 98%以上 ,Westernblot表明表达抗原可与戊肝患者阳性血清特异性结合 ;在HEV感染恒河猴实验中用于IgG抗体的检测 ,具有较好灵敏度与特异性 ;用其免疫豚鼠 ,抗体经ELISA法测定效价为 1∶80 0 0 ;用制备的豚鼠抗血清捕获戊型肝炎病毒颗粒 ,经RT nPCR扩增出特异性片段。结论　ORF2 3抗原片段具有HEV抗体识别的抗原表位 ,能够刺激机体产生抗体 ,抗血清具有一定的识别与结合戊型肝炎病毒颗粒的能力     

丙型肝炎病毒及恶性疟原虫复合抗原基因表达及诱导小鼠免疫应 …

将合成的丙型肝炎病毒（ＨＣＶ）复合多表位抗原基因ＰＣＸ及恶性疟原虫（Ｐｆ）多价抗原基因ＡＢ（ＳＰｆ６６＋ＳＰｆ１０５）克隆到表达载体ｐ＾ＷＲ４５０－１中,以β－半乳糖甘酶（ＧＺ）－ＨＣＶ－Ｐｆ复合多肽抗原的形式在大肠杆菌中高效融合表达了目的蛋白ＧＺ－ＣＡＢ,表达量约３０％。所表达的重组抗原可被ＨＣＶ患者血清及鼠抗Ｐｆ抗体特异识别,显示了该融合蛋白质具有ＨＣＶ和Ｐｆ的免疫原性。该蛋白免疫小鼠后,诱发     

1995至2000年北京地区散发性急性肝炎患者肝炎病毒抗体的检测与分析

目的 了解北京市地区散发性肝炎患者甲型、乙型、丙型和戊型肝炎病毒感染型别分布及重叠感染。方法 用EIA法检测1995斫2月至2000年12月北京地区散发性急性肝炎患者抗－HAVIgM、HBsAg／抗－HBcIgM、抗－HCVIgM/IgG和抗－HEVIgM/IgG。结果 214例散发性急性肝炎患者血清,抗甲、乙、内和戊型肝炎病毒IgM总阳性数155例,戊型肝炎76例。有9名患者检出2种肝炎病毒抗原或抗体阳性,其中在3名肝硬化患者和2名静脉吸毒者同时检测到HBV和HCV抗原或抗体,1例HBsAg阳性者检测到抗－HAVIgM,3例－HCVIgG阳性者中分别检测到2例抗－HBVIgM和1例抗－HEVIgM。肝炎病毒重叠感染的9名患者年龄在31岁至49岁之间。结论 北京地区散发性急性肝炎78％是由消化道传染的甲戊型肝炎病毒引起,戊型肝炎在四种肝炎中位居首位,其次为甲型肝炎、乙型肝炎和丙型肝炎。肝炎病毒重叠感染多见乙、丙型肝炎病毒合并感染或慢性乙、丙型肝炎患者合并甲型或戊型肝炎病毒感染。在我国对散发性病毒性肝炎的预防应引起高度重视。     

戊型肝炎病毒中国株结构区ORF2 cDNA的克隆及表达

将戊型肝炎病毒（ＨＥＶ）中国株结构区第二开放读码框架（ＯＲＦ２）８３７ｂｐ ｃＤＮＡ片段插入ｐＧＥＸ１λＴ质粒中进行表达。经免疫吸印法证明，该质粒表达的融合蛋白具有识别抗－ＨＥＶ的抗原表位，可用于制备抗－ＨＥＶ检测试剂。     

中国株庚型肝炎病毒C(GBV-C)感染的检测及部分核酸序列测定

国内首次采用合成肽抗原筛查高危人群血液中的庚型肝炎病毒Ｃ（ＧＢＶ－Ｃ）抗体。单采浆站供血者ＧＢＶ－Ｃ抗体阳性率为０．４４％（１１／２５００）；非甲－戊型肝炎患者ＧＢＶ－Ｃ抗体阳性率为６．６７％（２／３０）。抗体阳性血清再用ＲＴ－ＰＣＲ法检测ＧＢＶ－ＣＲＮＡ。部分扩增产物进行了核苷酸序列测定，其核苷酸序列与Ｓｉｍｏｎｓ等报道的ＧＢＶ－Ｃ序列同源性为８９．０９％至９２．４８％。该研究提示，ＧＢＶ－Ｃ可能不是非甲－戊型肝炎的主要致病因子，可能存在ＧＢＶ－Ｃ健康携带者，应尽快研制出ＧＢＶ－Ｃ感染检测试剂盒，以筛选献血员。     

一种新型戊型肝炎病毒样颗粒的表达、纯化及其免疫原性

目的以非包涵体形式表达含戊型肝炎病毒(HEV)中和抗原表位的新型HEV重组蛋白,并对其进行鉴定和分析。方法将HEV开放阅读框架2(ORF2)编码452~617位氨基酸的基因片段连接到载体pET28a( ),转化大肠杆菌,获取表达克隆。以Ni-NTA层析柱纯化表达的蛋白,并用SDS-PAGE、Westernblot和直接电镜负染等方法分析鉴定,最后免疫小鼠检测特异性抗体的产生水平。结果表达的重组蛋白天然可溶,相对分子质量(Mr)约为22000,并可形成直径为20nm左右的病毒样颗粒,能与戊型肝炎患者血清发生Westernblot阳性反应,免疫小鼠后可诱导产生高滴度的特异性抗体。体外中和试验显示产生的抗体具有中和HEV的活性。结论原核表达的、含HEV中和抗原表位的、长度仅166个氨基酸的HEVORF2近3′端编码蛋白能够形成病毒样颗粒,而且该新型病毒样颗粒具有良好的抗原性和免疫原性。     

新型戊型肝炎病毒ORF2部分基因的构建表达及表达产物的抗原性分析

目的对新型戊型肝炎病毒ORF2的3′端部分基因进行重组质粒构建及融合表达,并对表达蛋白进行抗原性分析。方法用PCR方法从含有HEVORF2基因的pGEM-T载体上扩增表达片段,双酶切后与原核表达载体pThioHisA构建重组质粒pThioHisA-T11。诱导表达后进行SDS-PAGE和免疫印迹分析。并用纯化的融合蛋白建立EIA检测方法,对40份抗-HEVIgG国家参比血清进行检测。结果含有pThioHisA-T11重组质粒的菌株表达相对分子质量为40×103的可溶性融合蛋白T11,免疫印迹证明融合蛋白T11能与抗HEVIgG发生特异反应。EIA检测结果显示,阳性参比血清符合率为80%(8/10),阴性参比血清符合率为87%(26/30),总符合率为85%。结论表达了新型HEVORF2羧基端278氨基酸并证明有抗原活性,为今后提高HEV检出率奠定了基础。     

一个能诱生戊型肝炎病毒中和抗体的ORF2编码蛋白短片段

目的：比较戊型肝炎病毒（HEV）第4基因型ORF2编码蛋白片段pN472-C617（aa472～617）和pN477-C613（aa477～613）的免疫原性，找到能诱生HEV中和抗体的ORF2编码蛋白的更短片段。方法：表达和纯化pN472-C617和pN477-C613，分别免疫BALB/c小鼠，以间接ELISA检测免疫血清的抗体效价，并以基于PCR的体外中和试验检测免疫血清的中和活性。结果：pN472-C617和pN477-C613可在大肠杆菌高效可溶性表达，纯化后的重组蛋白能在小鼠体内诱导出高效价的抗体。基于PCR的体外中和试验显示pN472-C617免疫血清可有效中和HEV，阻断其在敏感细胞表面的吸附和细胞内复制；而两端仅比pN472-C617各短5个氨基酸的pN477-C613的免疫血清不具有中和HEV的活性。结论：重组蛋白pN472-C617具有良好的抗原性和诱生中和抗体的能力，是目前文献报道中含有HEV中和抗原表位的最短ORF2编码蛋白片段，可作为重组亚单位候选疫苗用于HEV疫苗的开发。     

恶性疟原虫海南株var2csa基因的克隆、表达及免疫识别研究

目的克隆、表达恶性疟原虫海南株HN（2）var2csa基因DBL4、DBL5、DBL6区,通过ELISA方法比较其与硫酸软骨素A（CSA）的亲和能力差异,以及人体对恶性疟原虫海南株HN（1）、（2）VAR2CSA不同DBL区的免疫应答差异。方法根据DBL区序列设计3对引物,PCR扩增目的片段,并与pMD18-T克隆载体连接。经PCR、酶切、测序鉴定正确后克隆至表达载体pET-22b,通过转化、诱导、纯化表达重组蛋白质,SDS-PAGE和Western blot检测。通过ELISA方法进行重组蛋白质与CSA的粘附实验以及与患者血清的免疫识别实验。结果酶切及DNA测序结果均表明表达载体构建成功,表达并纯化3个DBL区重组蛋白质,分子量与预计大小相同,Western blott检测目的蛋白质具有免疫反应性,ELISA显示不同蛋白浓度条件下DBL5区均明显比其它两个DBL区有更高的OD405值,并且DBL5区被妊娠相关疟疾病人血清识别水平显著高。结论 var2csa基因3个DBL区重组蛋白质表达成功,DBL5区与CSA的粘附能力较强,人体对DBL5区的免疫应答反应可能在抗病免疫过程中起到关键作用。     

Immunodominant epitopes mapped by synthetic peptides on the capsid protein of avian hepatitis E virus are non-protective

Avian hepatitis E virus (avian HEV) was recently discovered in chickens with hepatitis-splenomegaly syndrome in the United States. The open reading frame 2 (ORF2) protein of avian HEV has been shown to cross-react with human and swine HEV ORF2 proteins, and immunodominant antigenic epitopes on avian HEV ORF2 protein were identified in the predicted antigenic domains by synthetic peptides. However, whether these epitopes are protective against avian HEV infection has not been investigated. In this study, groups of chickens were immunized with keyhole limpet hemocyanin (KLH)-conjugated peptides and recombinant avian HEV ORF2 antigen followed by challenge with avian HEV virus to assess the protective capacity of these peptides containing the epitopes. While avian HEV ORF2 protein showed complete protection against infection, viremia and fecal virus shedding were found in all peptide-immunized chickens. Using purified IgY from normal, anti-peptide, and anti-avian HEV ORF2 chicken sera, an in-vitro neutralization and in-vivo monitoring assay was performed to further evaluate the neutralizing ability of anti-peptide IgY. Results showed that none of the anti-peptide IgY can neutralize avian HEV in vitro, as viremia, fecal virus shedding, and seroconversion appeared similarly in chickens inoculated with avian HEV mixed with anti-peptide IgY and chickens inoculated with avian HEV mixed with normal IgY. As expected, chickens inoculated with the avian HEV and anti-avian HEV ORF2 IgY mixture did not show detectable avian HEV infection. Taken together, the results of this study demonstrated that immunodominant epitopes on avian HEV ORF2 protein identified by synthetic peptides are non-protective, suggesting protective neutralizing epitope on avian HEV ORF2 may not be linear as is human HEV.     

Identification and characterization of the neutralization epitope(s) of the hepatitis E virus

The neutralization epitope(s) of the hepatitis E virus (HEV) was studied by an in vitro neutralization assay using antibodies obtained by immunization of mice with 51 overlapping 30-mer synthetic peptides spanning the region 221-660 amino acids (aa) of the HEV open reading frame 2 encoded protein (pORF2) and 31 overlapping recombinant proteins of different sizes derived from the entire pORF2 of the HEV Burma strain. Antibodies against synthetic peptides and short recombinant proteins of approximately 100 aa did not neutralize HEV, suggesting the HEV neutralization epitope(s) is conformation-dependent. However, one recombinant protein of approximately 400 aa in length comprising the pORF2 sequence at position 274-660 aa as well as all truncated derivatives of this protein containing region 452-617 aa elicited antibodies, demonstrating HEV neutralizing activity. These findings establish for the first time that the minimal size fragment, designated pB166, that can efficiently model the neutralization epitope(s) is 166 aa in length and is located at position 452-617 aa of the HEV pORF2. Additionally, antibodies against pB166 were found to cross-neutralize three different HEV genotypes, suggesting that a common neutralization epitope(s) may exist within the different HEV genotypes. Thus, recombinant proteins constructed in this study may be considered as potential candidates for the development of an HEV subunit vaccine as well as for the development of highly sensitive and specific diagnostic tests.     

抗戊型肝炎病毒噬菌体抗体库的构建与筛选

目的 :构建人抗戊型肝炎病毒 (HEV)噬菌体抗体库 ,筛选人源中和性抗HEV的单克隆抗体 (mAb)。方法 :取抗HEV抗体阳性的 6例HE患者静脉血 ,分离淋巴细胞 ,提取细胞总RNA后逆转录。用一组人IgGFab基因特异性引物 ,分别扩增IgGκ0轻链与重链Fd段基因。将κ轻链与Fd段基因先后克隆入噬菌体载体pComb3的相应位点 ,经电穿孔法转化大肠杆菌XL1 Blue ,再以辅助噬菌体VCSM13超感染 ,构建人抗HEV噬菌体抗体库。采用独特的 5轮筛选法 (逐渐降低抗原包被量 ,严格洗脱条件 ) ,以固相化的 4种含中和抗原表位的HEV代表株ORF2重组混合抗原 ,筛选人噬菌体抗体库 ,并以ELISA鉴定噬菌体抗体。结果 :经数次电转化构建了容量为1.9× 10 7重组率为 80 %的κ轻链基因库 ;容量为 1.8× 10 7重组率为 2 0 %的Fab基因库。以含中和抗原表位的HEV代表株ORF2重组混合抗原特异淘筛 5次 ,出现特异富集。ELISA鉴定第 5轮筛选产物 ,得到 4株与HEVORF2重组混合抗原具有较高亲和力的Fab噬菌体抗体 ,可能为中和抗体。结论 :成功地构建了人抗HEV噬菌体抗体库 ,并获得人源抗HEV特异性噬菌体抗体。     

恶性疟原虫红细胞表面膜蛋白1DBLα区不同区段与血型抗原的结合特性分析

根据大肠杆菌密码子组成特点,重新优化并合成FCR3S1.2株恶性疟原虫红细胞表膜蛋白1(PfEMP1)DBLα区基因序列,利用PCR的方法,将优化后的基因序列分为3段.分别将全长基因和3个基因片段在大肠杆菌中表达、纯化.通过重组蛋白与血型抗原的亲和试验,分析功能区与血型抗原是否具有亲和力.结果表明,重组的PfEMP1-...     

Identification of VAR2CSA Domain-Specific Inhibitory Antibodies of the Plasmodium falciparum Erythrocyte Membrane Protein 1 Using a Novel Flow Cytometry Assay

VAR2CSA, a member of the Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family, is a leading candidate for use in vaccines to protect first-time mothers from placental malaria (PM). VAR2CSA, which is comprised of a series of six Duffy binding-like (DBL) domains, binds chondroitin sulfate A (CSA) on placental syncytiotrophoblast. Several recombinant DBL domains have been shown to bind CSA. In order to identify and develop recombinant proteins suitable for clinical development, DBL2X and DBL3X, as well as their respective third subdomain (S3) from the FCR3 parasite clone, were expressed in Escherichia coli, refolded, and purified. All but DBL3X-S3 recombinant proteins bound to CSA expressed on Chinese hamster ovary (CHO)-K1 cells but not to CHO-pgsA745 cells, which are CSA negative as determined by flow cytometry. All but DBL3X-S3 bound to CSA on chondroitin sulfate proteoglycan (CSPG) as determined by surface plasmon resonance (SPR) analysis. Purified IgG from rats and rabbits immunized with these four recombinant proteins bound homologous and some heterologous parasite-infected erythrocytes (IE). Using a novel flow cytometry inhibition-of-binding assay (flow-IBA), antibodies against DBL3X-S3 inhibited 35% and 45% of IE binding to CSA on CHO-K1 cells compared to results for soluble CSA (sCSA) and purified multigravida (MG) IgG, respectively, from areas in Tanzania to which malaria is endemic. Antibodies generated against the other domains provided little or no inhibition of IE binding to CSA on CHO-K1 cells as determined by the flow cytometry inhibition-of-binding assay. These results demonstrate for the first time the ability to identify antibodies to VAR2CSA DBL domains and subdomains capable of inhibiting VAR2CSA parasite-IE binding to CSA by flow cytometry. The flow cytometry inhibition-of-binding assay was robust and provided an accurate, reproducible, and reliable means to identify blocking of IE binding to CSA and promises to be significant in the development of a vaccine to protect pregnant women.