诺如病毒表达衣壳蛋白单克隆抗体的制备、鉴定和初步应用

目的:建立能稳定分泌抗诺如病毒(Norovirus)N蛋白的单克隆抗体(mAb)细胞株, 制备抗诺如病毒核衣壳蛋白的mAb, 为诺如病毒的早期快速检测及致病机制的研究提供实验材料.方法:用E.coli表达的GⅡ组广州株NVgz01(DQ369797)Norovirus-N蛋白免疫BALB/c小鼠, 通过PEG使小鼠脾细胞和Sp2/0细胞融合, 使用HAT选择性培养基培养融合细胞, 用间接ELISA和Western blot测定mAb的效价、免疫球蛋白亚型和mAb的特异性, 并将各mAb之间进行配对.结果:通过细胞融合和克隆化, 共筛选出4株分泌抗Norovirus-N蛋白抗体的杂交瘤细胞株N2C3、 N7C2、 N4B1、 N8A9.间接ELISA和Western blot检测结果表明, 这4株mAb都可以与E.coli表达的GⅡ组广州株Norovirus-N蛋白产生特异性反应, 并且能与天然粪便标本中的GⅡ组Norovirus产生特异性反应.配对结果显示N2C3和N7C2之间配对, 对表达蛋白和天然病毒都具有较强的检测灵敏度.结论:获得了诺如病毒GⅡ组特异性mAb, 为制备免疫诊断试剂盒及致病机制的研究奠定了基础.     

A characterization of epitopes on potato leafroll virus coat protein

Summary A panel of ten stable hybridoma cell lines secreting monoclonal antibodies (MAbs) specific for potato leafroll virus (PLRV) antigen, was produced in two fusion experiments with murine splenic and myeloma cells. Using different ELISA procedures and Western blotting it was shown that one MAb detected a continuous epitope and nine MAbs reacted with conformation-dependent ones. The conformation-dependent epitopes could be separated into two groups after alkaline treatment of the virions. The MAbs were further differentiated in competitive binding assays. Within the group of MAbs reacting with epitopes not sensitive to alkaline degradation, only two MAbs were directed to the same epitope. The MAbs detecting epitopes formed by the quaternary protein structure or by a protein subunit configuration sensitive to alkaline degradation, displayed positive cooperative binding among each other. In total, a minimum number of nine different, but overlapping, epitopes on the PLRV coat protein could be revealed.The immune response to PLRV antigen in rabbit appeared to be directed mainly towards epitopes recognized by three MAbs.Most MAbs displayed heterologous reactivity to other luteoviruses, i.e., tomato yellow top virus (TYTV), beet western yellow virus (BWYV), beet mild yellowing virus (BMYV), bean leafroll virus (BLRV), and different strains of barley yellow dwarf virus. Three MAbs solely reacted with PLRV and TYTV. Six MAbs gave different reaction patterns in these tests; one of these MAbs differentiated BMYV from BWYV, and another detected a common epitope on PLRV and BLRV, a serological relationship not reported previously to our knowledge.     

Cross-reactivity among several recombinant calicivirus virus-like particles (VLPs) with monoclonal antibodies obtained from mice immunized orally with one type of VLP

Human caliciviruses (HuCVs) are classified into the Norwalk-like viruses (NLV) and Sapporo-like viruses (SLV) as genera within the family CALICIVIRIDAE: The NLV genus is further classified into genogroups I and II, based on sequence similarities. To study the antigenic determinants on the HuCV capsid protein and develop new diagnostic tools for field samples, we established and characterized monoclonal antibodies (MAbs) against baculovirus-expressed recombinant HuCV virus-like particles (VLPs). Hybrid clones producing MAbs were obtained from cultures of PAI myeloma cells fused with spleen or mesenteric lymph node cells from mice immunized orally with either a single type of recombinant Norwalk virus (rNV), Kashiwa 47 virus (rKAV), Snow Mountain agent (rSMA), or Sapporo virus (rSV) VLP or with mixtures of two types of VLPs from different genogroups. Twenty MAbs, obtained as mouse ascites, were characterized and classified into six groups according to their enzyme-linked immunosorbent assay (ELISA) and Western blotting (WB) cross-reactivity patterns to VLPs. Five groups of MAbs reacted by both WB and ELISA and were classified as follows: common cross-reactive MAbs for four genogroup I and six genogroup II VLPs (group A), genogroup I-specific MAbs (group B), genogroup II-specific MAbs (group C), and strain-specific MAbs (groups D and E). One MAb group (group F) reacted only by ELISA. The group A MAbs, which showed broad cross-reactivity with VLPs of both NLV genogroups, were obtained from mice immunized orally with a single type of VLP (either rNV or rKAV). Two MAbs, which were obtained from mice immunized with rSV, reacted with rSV but not with any NLV VLP. These are the first MAbs to be reported for any SLV. These strain-, genogroup-, and genus-reactive MAbs will be useful tools for further study of the antigenic and structural topography of the HuCV virion and for diagnostic assays for HuCVs.     

西尼罗病毒E蛋白结构域Ⅲ特异性单克隆抗体的研制

目的研制针对西尼罗Ⅲ重组融合蛋白的特异性单克隆抗体。方法用西尼罗Ⅲ重组融合蛋白免疫BALB／c小鼠，用淋巴细胞杂交瘤技术进行细胞融合，并用间接ELISA方法进行筛选，所获得的单抗经间接ELISA、免疫印迹和间接免疫荧光试验进行鉴定。结果共获得了3株能稳定分泌针对西尼罗河病毒E蛋白结构域Ⅲ的特异性单抗的杂交瘤细胞株，分别命名为4F7、6H3和8FA，其单抗亚类鉴定分别属于IgG1、IgG1和Ig2a。这3株单克隆抗体均能与重组西尼罗河病毒E蛋白结构域Ⅲ发生特异性反应，而与日本脑炎病毒无交叉反应，并且，8FA和6H3识别同一抗原位点，4F7识别西尼罗河病毒E蛋白结构域Ⅲ的另一抗原位点。结论本实验成功研制出针对西尼罗河病毒E蛋白结构域Ⅲ的特异性单克隆抗体，为我国建立西尼罗河病毒的病原学检测方法并与日本脑炎病毒进行鉴别诊断提供了技术贮备。     

Production,characterization and use of monoclonal antibodies to grapevine virus A

Summary Four stable hybridoma cell lines secreting monoclonal antibodies to grapevine closterovirus A (GVA) were obtained by fusing spleen cells of immunized BALB/c mice with mouse myeloma cell line Sp 2/0-Ag 14. In ELISA all MAbs reacted with virus in leaf extracts fromNicotiana benthamiana, glass-house-, field-, or in vitro-grown grapevines, or with cortical shavings from mature grape canes. In IEM tests, only one of the MAbs (PA 3.F 5) decorated virus particles on the entire surface. This MAb was likely induced by a surface antigenic determinant, whereas the other three MAbs (PA 3.D 11, PA 3.C 6, and PA 3.B 9) were originated by cryptotopes. Coupling polyclonal antibodies for coating protein A-sensitized plates, and monoclonal antibody conjugates for antigen detection, gave highly efficient and reproducible results for identification of GVA in field-grown grapevines.     

An improved enzyme linked immunosorbent assay for detection of anti-ranavirus antibodies in the serum of the giant toad (Bufo marinus)

An improved ranavirus antibody ELISA (R Ab ELISA) for the specific detection of anti-ranavirus antibodies in toad sera was developed. Sheep anti-epizootic haematopoietic necrosis virus (EHNV) was used as the antigen-capture antibody. EHNV was used as the antigen and sera from field and challenged toads were used to detect the virus. Rabbit anti-toad IgG and IgM were used to detect bound toad antibody. Pre-absorption of toad sera with a monoclonal antibody, raised against the 50 kDa EHNV protein, improved the specificity of the technique. A blocking ELISA, immunofluorescence and immuno-electron microscopy were used to confirm the validity of the ELISA. The assay has potential use in screening sera from Bufo marinus for the presence of antibodies against ranaviruses and to facilitate understanding of the humoral immunological response in toads during virus infection.     

HCV NS3蛋白单克隆抗体的制备及其识别区域的分析

目的 制备针对丙型肝炎病毒（HCV）非结构区NS3全长蛋白的单克隆抗体（MAb），并分析获得的单抗识别表位所在区域，为建立以NS3蛋白为靶位的抗HCV研究提供抗体工具。方法 用原核表达的HCV非结构区NS3全长蛋白作为免疫原，采用小鼠腹股沟皮下NC膜包埋法免疫小鼠，按常规杂交瘤细胞的制备方法，经细胞融合、克隆化制备抗NS3蛋白的MAb。用间接免疫荧光法和Westem blot鉴定其特异性。分别构建NS3丝氨酸蛋白酶（NS3蛋白的N末端1／3）编码基因的真核表达质粒pcDNA3．1（-）-ns3p、NS3解旋酶（NS3蛋白的C末端2/3）编码基因的真核表达质粒pcDNA3．1（-）-ns3A，将其瞬时转染COS-7细胞后，以获得的单克隆抗体作为一抗，通过免疫荧光分析获得单抗识别表位所在的区域。结果 获得了2株抗NS3蛋白的单克隆抗体，这2株MAbs均特异识别NS3蛋白，并确定了它们的结合区域。结论 获得了针对NS3蛋白的单克隆抗体，并对其单抗识别表位所在的区域进行了分析，为下一步进行以NS3蛋白为靶位的抗HCV研究奠定了良好的基础。     

抗人hnRNP A1单克隆抗体的制备及在颅咽管瘤组织中的应用

目的制备核不均一核糖核蛋白Al（heterogeneous nuclear ribonucleoprotein Al，hnRNPAl）的单克隆抗体，探讨hnRNP Al蛋白的生物学功能。方法利用重组hnRNPA1蛋白为免疫原，免疫BALB／c小鼠。取免疫小鼠的脾细胞和同系小鼠的骨髓瘤细胞SP2／0进行常规融合，通过间接ELISA的筛选和有限稀释克隆化。获得鼠抗hnRNPAl单克隆抗体的杂交瘤细胞株，通过ELISA、Western Blot和免疫组织化学实验等方法分别对其效价和特异性进行鉴定。结果成功地建立了3株稳定分泌抗hnRNPAl的单克隆抗体杂交瘤细胞株。分别命名为E006、E009和E012。3株单克隆抗体的免疫球蛋白亚类均为IgG1。3株单克隆抗体通过组织化学实验和Western Blot实验都能特异性地结合真核细胞内源性的hnRNPAl蛋白。结论获得了效价高、特异性好的抗hnRNPAl蛋白的单克隆抗体，这为进一步研究hnRNPAl的生物学功能及它在癌发生事件中的作用奠定了基础。     

抗土拨鼠肝炎病毒核心蛋白单克隆抗体的制备、性质鉴定及初步应用

目的研制出能特异与土拨鼠肝炎病毒核心蛋白（WHc）结合的单克隆抗体,使之能特异性地对土拨鼠肝炎病毒（WHV）进行检测,并可能应用于相关肝炎病毒的筛查。方法以原核表达的土拨鼠肝炎病毒重组核心蛋白（WHc 1～149氨基酸）免疫BALB/c小鼠,常规杂交瘤技术进行细胞融合,有限稀释法克隆化,间接酶联免疫吸附试验（ELISA）和免疫组织化学（IHC）筛选、鉴定。结果筛选出5株（4B1E、6C5D、6C5C、6D1D、6D1G）能稳定分泌抗土拨鼠肝炎病毒核心蛋白抗体的杂交瘤细胞株。此5株单抗适用于ELISA、IHC、Western blot等方面的研究,与HBcAg有交叉反应,并且在部分中国旱獭的肝脏组织进行IHC检测呈现阳性反应。结论制备的5株单抗可用于土拨鼠肝炎病毒等嗜肝脱氧核糖核酸病毒的研究,可能在寻找新的相关肝炎病毒中起重要作用。     

Production of monoclonal antibodies specific for Haemophilus ducreyi: a screening method to discriminate specific and cross-reacting antibodies

Haemophilus ducreyi is the etiological agent of chancroid. The organism shares extensive immunological cross-reactivity with other Haemophilus species. This presents substantial difficulties for the production of specific monoclonal antibodies (MAbs). A competition ELISA was devised for hybridoma screening which allowed the detection of H. ducreyi-specific antibody-producing hybridoma cultures during the initial screening process. With this screening method, seven MAbs specific for H. ducreyi were obtained in a single cell fusion exercise. The specificities of the 7 MAbs were demonstrated by direct ELISA and dot immunobinding assays against several strains each of H. influenzae, H. parainfluenzae and Neisseria gonorrhoeae. Five of the MAbs reacted against all ten strains of H. ducreyi. These MAbs may permit the development of rapid and efficient immunodiagnostics for chancroid. The principle of the competition ELISA for hybridoma screening should be widely applicable to the development of specific MAbs to other organisms in which immunological cross-reactivity is an impediment to hybridoma screening by conventional methods.     

抗AIV(H9)独特型单克隆抗体的制备及其免疫原性的研究

用H9N2亚型AIV作为抗原免疫接种SPF鸡制备高免血清,用饱和硫酸铵法从该血清中提取免疫球蛋白G(IgG)。以该IgG制备弗氏佐剂疫苗免疫SPFBALB/c小鼠,取其脾细胞与小鼠骨髓瘤细胞NS-1在聚乙二醇(PEG)作用下融合,采用间接ELISA检测法,筛选获得3株(2H1D1、2H1G4、3H2D7)分泌特异性单克隆抗体的杂交瘤细胞。3株融合细胞培养上清液中的单克隆抗体效价均为2-4,小鼠腹水中的单抗效价是细胞培养上清液中的300～500倍。经检测表明,3株细胞系产生的单克隆抗体仅与相应的鸡抗H9N2亚型AIV血清发生特异性反应。用2H1D1分泌的抗独特型单克隆抗体制备疫苗与抗AIV灭活疫苗同时免疫SPF鸡收获的高免血清与AIV在MDCK细胞上进行中和实验,中和效价分别为10-1.8/10μl、10-1.6/10μl。由此表明,该抗独特型抗体疫苗具有良好的免疫原性。     

Mapping of epitopes of VP2 protein of chicken anemia virus using monoclonal antibodies

To map the epitopes of VP2 protein of chicken anemia virus (CAV), VP2 was expressed as a fusion protein in Escherichia coli BL21 (DE3). The Western blot demonstrated that recombinant VP2 protein could be recognized by sera of chickens infected with CAV. Female BALB/c mice were immunized with purified recombinant VP2 produced in E. coli BL21 (DE3) and seven VP2-specific monoclonal antibodies (MAbs) were developed. The results of Western blot showed that all the seven MAbs recognized the recombinant VP2 protein expressed in the baculovirus and reacted with MDCC-MSB1 cells infected with CAV by indirect immunofluorescence assay. The VP2 protein was dissected into 21 overlapping fragments, expressed as fusion peptides in E. coli and used for epitope mapping by pepscan analysis. ELISA and Western blot assays indicated that most of MAbs reacted with the 12th and 13th fragments (amino acids 111-136) and one of them reacted with the 3rd fragment (amino acids 21-36). The linear immunodominant epitope of VP2 was located mainly in amino acid residues 111-126 and 121-136.     

Characterization of Zaire ebolavirus glycoprotein-specific monoclonal antibodies

Zaire ebolavirus (ZEBOV) can be transmitted by human-to-human contact and causes acute haemorrhagic fever with case fatality rates up to 90%. There are no effective therapeutic or prophylactic treatments available. The sole transmembrane glycoprotein (GP) is the key target for developing neutralizing antibodies. In this study, recombinant VSVΔG/ZEBOVGP was used to generate monoclonal antibodies (MAbs) against the ZEBOV GP. A total of 8 MAbs were produced using traditional hybridoma cell fusion technology, and then characterized by ELISA using ZEBOV VLPs, Western blotting, an immunofluorescence assay, and immunoprecipitation. All 8 MAbs worked in IFA and IP, suggesting that they are all conformational MAbs, however six of them recognized linearized epitopes by WB. ELISA results demonstrated that one MAb bound to a secreted GP (sGP 1-295aa); three bind to a part of the mucin domain (333-458aa); three MAbs recognized epitopes on the C-terminal domain of GP1 (296-501aa); and one bound to full length GP (VLPs/GP1,2 ΔTm). Using a mouse model these MAbs were evaluated for their therapeutic capacity during a lethal infection. All 8 MAb improved survival rates by 33%-100% against a high dose lethal challenge with mouse-adapted ZEBOV. This work has important implications for further development of vaccines and immunotherapies for ZEBOV infection.     

Development of a monoclonal antibody specific for serotype 3 rotavirus strains

Monoclonal antibodies were prepared against serotype 3 simian rotavirus SA11. Antigenic analysis of 18 hybridoma cell lines secreting monoclonal antibodies by radioimmunoprecipitation and Western blot revealed that seven monoclonals were directed against the major inner capsid protein VP6, four against VP3, an outer capsid protein with hemagglutinating activity, and one against VP7, the main outer capsid protein of the virus. The specificity of six monoclonals could not be determined. One monoclonal (1P14E2) directed against VP3 showed serotype 3-specific neutralizing activity. This monoclonal, which recognized only serotype 3 viruses in an enzyme-linked immunosorbent assay, could be useful in assays for serotyping rotavirus directly in stool samples.     

Development of a capsid based competitive inhibition enzyme-linked immunosorbent assay for detection of bovine immunodeficiency virus antibodies in cattle and buffalo serum

The aim of this study was to develop a more specific and sensitive competitive inhibition ELISA (CI-ELISA) than the currently used indirect ELISA for detection of antibodies to bovine immunodeficiency virus (BIV) in cattle and buffaloes. Murine monoclonal antibodies (MAbs) were generated against a recombinant capsid (CA) protein of bovine immunodeficiency virus. Of the 13 anti-CA MAbs developed, MAb-9G10 was selected for CI-ELISA based on the maximum inhibition (98%) obtained with reference BIV antibody positive serum. Based on the distribution of percent inhibition of known negative sera (n=50), a cut-off value was set at 40% inhibition. The MAb-based CI-ELISA showed much higher agreement (concordance: 95.4%) than the indirect ELISA (concordance: 77.8%) with Western blot. Out of 672 sera of cattle and buffaloes tested by CI-ELISA from four states of India, 22% (113/516) of cattle and 19% (30/156) of buffalo were sero-positive for BIV with an overall seroprevalence of 21% (143/672) in India.     

自制NSE单抗的鉴定及其双抗夹心ELISA方法的建立

目的:制备并鉴定NSE(Neuron-specific enolase)单克隆抗体,建立可检测NSE蛋白的双抗夹心ELISA方法。方法:用本实验室已表达纯化的NSE融合蛋白免疫BALB/c小鼠,采用杂交瘤技术制备单克隆抗体。采用WB、IP、IF、IHC等方法对获得的NSE单抗进行鉴定及亚型检测。利用辣根过氧化物酶标记纯化后的NSE单抗,建立一个可检测NSE蛋白的双抗夹心ELISA法。结果:通过分析和鉴定,选定2株可稳定分泌抗NSE抗体的杂交瘤细胞株,效价达4.2×107～6.5×107,亚型为IgG2b。免疫印迹结果显示,该抗体不仅能识别细胞内源NSE蛋白,还能识别分泌到细胞培养上清液中的NSE蛋白,此外还可用于免疫荧光及免疫组化检测。文中所建立的双抗夹心ELISA法,最低检测极限为8.85 ng/ml。结论:成功获得了效价高、灵敏度好及特异性强的NSE单抗,建立了一个双抗体夹心ELISA检测系统,具有良好的临床应用前景。     

Development and characterization of neutralizing monoclonal antibodies against the pandemic H1N1 virus (2009)

The 2009 H1N1 influenza pandemic was a major international public health crisis which caused considerable morbidity and mortality worldwide. The goal of this study was to produce anti-H1 monoclonal antibodies (MAbs) for improving diagnostic immunological assays and to develop potential immunotherapeutics. Nine MAbs were produced after immunizing mice with recombinant hemagglutinin (HA) protein from A/California/06/09. Two spleenocyte myeloma fusions yielded 1588 hybridoma cultures. After screening the hybridoma culture supernatants for antibody reactivity to rHA, nine clones were selected for further characterization. Cross-reactivity studies of the anti-rHA antibodies against a panel of influenza viruses (H1-H16) revealed eight out of nine MAbs were specific to the pandemic H1 subtype, except for MAb F256G2sc1 which also cross-reacted with H5 subtype virus. All MAbs were of the IgG1κ isotype, except F256G2sc1 which was IgG2aκ. The anti-rHA MAbs had binding affinities to rHA that ranged from a K(D) (disassociation constant) of 1.34×10(-9)M (F255G7sc1) to the weakest affinity of 4.60×10(-8)M (F255G4sc1). Interestingly, in a plaque reduction neutralization assay, all MAbs except F255G3sc1 demonstrated neutralizing ability. Furthermore, all MAbs except F255G3sc1 and F255G9sc1 exhibited anti-hemagglutinin activity against pandemic H1N1 viruses, but not against classical North American swine influenza viruses of the same subtype. Immunofluorescence assay (IFA) demonstrated that all MAbs except F255G1sc1 and F255G3sc1 were able to detect 2009 pandemic H1N1 (2009) virus- infected MDCK cells. The MAbs were also evaluated for potential use in competitive ELISA (cELISA), and with the exception of F255G3sc1, all MAbs showed competitive activity with serum collected from pigs infected with pandemic H1N1 virus (2009). The developed MAbs have demonstrated utility as immunodiagnostic and research reagents, and their neutralizing capabilities also hold potential for designing antiviral drugs against pandemic influenza.     

A monoclonal antibody to ICP4 of MDV recognizing ICP4 of serotype 1 and 3 MDV strains

Monoclonal antibodies (MAbs) were prepared against ICP4 of Marek's disease virus (MDV). Mice were inoculated with ICP4 obtained from High-Five insect cells infected with a recombinant baculovirus expressing ICP4. MAbs were selected by enzyme-linked immunosorbent assay (ELISA) using MDV-infected and control chick kidney cells as antigens. One of the MAbs, 5H8, recognized an epitope toward the carboxyl terminus of ICP4 based on staining of reticuloendotheliosis virus-transformed cells transfected with full-length and truncated ICP4 constructs. This MAb recognized ICP4 in chicken embryo fibroblasts (CEFs) infected with MDV strains JM16 and HVT but not with SB-1 strain. Using Western blot analysis a protein of 155 kDa was detected in CEFs infected with JM16 and HVT strains.     

Monoclonal antibodies against a plant virus

Summary Eight stable hybridoma clones derived from fusion of spleen cells of Tobacco Mosaic Virus (TMV) immunized mice with murine myeloma cells were grown in mass culture. They were obtained by 2 subsequent limiting dilution cloning cycles and subcultivation. Five of these clones secreted monoclonal antibodies which reacted with TMV nucleocapsid but not with capsid monomers and the monoclonal antibodies secreted by 3 other clones reacted with the TMV capsid monomer but not with the nucleocapsid. The specificity was determined by Enzyme Linked Immunosorbent Assay (ELISA) adjusted for the detection of antibodies in hybridoma culture supernatants.With 2 Figures