抗HSV-IICP22蛋白抗原多肽抗体对ICP22定位的检测分析

ICP22作为单纯疱疹病毒进入细胞后最早表达的蛋白之一,对于病毒的复制具有重要的调节功能,由于抗原表位的同源性,使用完整的ICP22蛋白作为抗原难以获得特异性的抗体.通过氨基酸序列预测,ICP22蛋白1～36位氨基酸具有较强的抗原性,将ICP22蛋白1-36位氨基酸偶联于GTS蛋白作为抗原免疫小鼠,所制备抗体能够特异性识别具有正常生理构象的ICP22蛋白.抗体检测结果显示,ICP22不但定位于细胞核内,而且还能够形成特殊的点状结构.     

HIV-1辅助蛋白Vpr多肽抗体的制备与鉴定

预测Vpr蛋白的B细胞抗原表位,并利用合成的B细胞表位肽制备Vpr特异性抗体。应用生物信息学技术获得Vpr蛋白共享氨基酸序列并预测其潜在B细胞抗原表位,与载体蛋白血蓝蛋白(KLH)偶联合成多肽并免疫家兔,鉴定及纯化获得的多肽特异性抗体。软件预测显示,Vpr蛋白N端的第3～19位(N)和C端的第82～95位(C)氨基酸序列为潜在B细胞抗原表位;ELISA检测抗血清中多肽特异性抗体的效价都达到1:105以上;Western-Blotting结果显示,无论对HIV-1B亚型还是CRF07_BC重组型的Vpr蛋白,其多肽N抗体和C抗体均能特异性识别;免疫沉淀结果显示,Vpr多肽N和C抗体也能特异性结合未变性的野生型Vpr或GFP-Vpr融合蛋白。利用生物信息学技术能成功预测Vpr蛋白B细胞抗原表位,免疫所获得的抗体具有较好的特异性和应用性。     

汉滩病毒S基因的分段表达及其线性和构象型抗原表位分析

构建汉滩病毒76—118N蛋白及其分别从N-端和C-端缺失的共6个突变体,在大肠杆菌BL-21中进行表达,并对其中一些蛋白进行了纯化。通过Western blot、酶联免疫吸附试验(ELISA)进行汉滩病毒N蛋白的抗原表位分析,N蛋白及6个缺失突变体都与组特异性抗体L13F3呈阳性反应,而缺失突变体与型特异性抗体AH30呈阴性反应。构建汉滩病毒76—118N蛋白及其6个缺失突变体的真核表达载体,并在COS-7细胞中进行表达。通过间接免疫荧光试验(IFA)进行汉滩病毒N蛋白的抗原表位分析,病人血清与真核表达的N蛋白及6个缺失突变体呈阳性反应。而仅有N蛋白及缺失N端1～30位氨基酸序列的NPN30与型特异性抗体AH30呈阳性反应。证实组特异性抗体L13F3结合的抗原表位位于N端1～30位氨基酸;而C端抗原表位对于型特异性抗体AH30与N蛋白的识别和结合具有重要意义,缺失N端100位氨基酸序列可能破坏羧基端构象型表位,也可以影响N蛋白与AH30的结合。     

单纯疱疹病毒1型立即早期蛋白ICP22研究进展

单纯疱疹病毒1型(Herpes simplex virus 1,HSV-1)感染细胞蛋白22(Infected Cell Protein 22,ICP22)是Us1基因编码的一种翻译后修饰多功能蛋白,为HSV-1的五种立即早期蛋白之一。HSV-1 ICP22能与不同的细胞和病毒成分相互作用来执行不同的功能,包括改变RNA聚合酶Ⅱ(RNA polymeraseⅡ,RNAPⅡ/PolⅡ)的磷酸化状态、参与抵抗细胞对病毒复制的消极作用、引起细胞周期蛋白A和B水平降低、介导修饰拓扑异构酶Ⅱα、参与胞核内病毒诱导的分子伴侣富集(Virus-induced chaperone-enriched,VICE)区域的形成及促进病毒新生核衣壳的初次包装。这些作用大多与调节病毒在胞核中有效复制相关。此外,HSV-1 ICP22还在限制细胞中的病毒复制、病毒致病力和潜伏感染建立过程中发挥重要作用,但ICP22发挥这些作用的机制尚未知。本文就上述目前国内外对HSV ICP22的研究进展作一综述,以期为后续研究提供参考。     

莱茵衣藻IFT22蛋白的原核表达、纯化及其多克隆抗体的制备

纤毛内运输蛋白IFT22是IFT复合物B中(IFT-B)的一个重要组分,但对其功能研究存在很大的争议,为深入研究IFT22功能,制备一支特异性好的IFT22抗体是必不可少的。该研究首先用纯度为93%的6×His标签IFT22抗原免疫新西兰大白兔,采集3次免疫后血清,间接ELISA法测定效价为1?64 000。抗血清经Protein A和抗原抗体纯化后, Western blot检测结果表明,以Chlamydomonas reinhardtii CC125全细胞为抗原时,孵育IFT22抗体后,只有一条带出现,说明anti-IFT22特异性非常好,是研究IFT22蛋白功能的绝佳材料。     

基于纳米抗体CDR3区抗原表位展示制备生存素抗体及其鉴定

目的:通过纳米抗体CDR3区展示生存素N端表位的方式,探索纳米抗体在抗原表位展示中的作用。方法:通过基因合成方法将生存素N端起始表位(氨基酸序列1~15)插入纳米抗体CDR3区,再构建到原核表达载体pET24a中,IPTG诱导表达,用带His标签的填料纯化,获得高纯度的目的蛋白,免疫雌性BALB/c小鼠,间接ELISA检测5次免疫后的效价,用抗原偶联纯化介质纯化免疫多抗,Western印迹检测多抗特异性。结果:IPTG诱导后,目的蛋白主要以包涵体形式存在,亲和层析获得纯度大于96%的目的蛋白,包涵体经复性后免疫小鼠,效价可达1∶512000,West?ern印迹特异性检测显示免疫多抗能够特异性结合生存素。结论:纳米抗体CDR3区生存素抗原N端表位展示的方法可用于抗生存素抗体的制备,并为今后纳米抗体表位展示相关研究奠定基础。     

SARS冠状病毒NS融合蛋白的重组表达纯化与免疫学性质分析(英文)

刺突蛋白(S)和核心蛋白(N)是SARS冠状病毒的主要结构蛋白.在病毒细胞受体结合和病毒包装过程起重要作用.重组融合表达这2种蛋白具有较高的诊断学价值.对SARS病毒N蛋白和S蛋白氨基酸序列进行计算机分析,选择含有优势抗原表位的N蛋白1～227位氨基酸片段和S蛋白450～650位氨基酸片段,采用序列重叠延伸策略(sequenceoverlappingextension,SOE)构建编码N1227LinkerS450650新型融合蛋白的基因片段,导入原核表达载体,实现融合蛋白在大肠杆菌的高效表达.利用组氨酸标签亲和层析的方法纯化,获得高纯度的融合蛋白.对该融合蛋白的结构特征模拟分析的结果显示,其免疫化学性质均无显著改变.采用ELISA和Western印迹方法对其识别SARS冠状病毒特异性抗体的能力进行初步鉴定,显示该融合蛋白具有较好的抗原性和特异性,可有效特异性地检测恢复期SARS病人血清中抗SARS冠状病毒结构蛋白的抗体,可以作为SARS冠状病毒感染的辅助诊断手段.     

Ⅲ型脊髓灰质炎病毒抗原表位嵌合蛋白的免疫学研究

目的:对以轮状病毒(RV)重组VP6蛋白为载体插入Ⅲ型脊髓灰质炎病毒(PV3)VP1蛋白上1个抗原表位(VP1的91~102、254和168位氨基酸残基)所构建的嵌合蛋白6F/PV3N1进行体外免疫学研究。方法:利用分子克隆和基因重组技术将PV3抗原表位插入RV载体蛋白,构建重组抗原表位嵌合蛋白表达质粒,转染大肠杆菌后表达重组蛋白,经SDS-PAGE确认表达产物,再通过Western印迹分析嵌合蛋白的抗原反应性。结果:用载体蛋白VP6F、轮状病毒Wa病毒株免疫的豚鼠血清抗体分别都能与VP6F和6F/PV3N1产生特异性结合;PV3免疫的豚鼠血清抗体只能与6F/PV3N1产生特异性结合,不能与VP6F产生特异性结合;PV1免疫的豚鼠血清抗体则不能与6F/PV3N1和VP6F产生特异性结合。结论:PV1、PV3之间不存在交叉反应现象,以RV VP6为载体构建的嵌合蛋白6F/PV3N1具有较好的免疫原性,为研发RV/PV3嵌合疫苗提供了基础。     

SM22-α蛋白结构与功能的生物信息学分析

[目的]通过生物信息学分析手段对SM22-α蛋白结构与作用进行系统性分析。[方法]从NCBI数据库中获取SM22-α蛋白的基本信息,应用NCBI GenBank、ExPAsy、TMHMM Server v.2.0、NetPhos 3.1 Server、IEDB、SIGNALP 5.0 Server等生物信息学分析软件对SM22-α蛋白的氨基酸序列、理化性质、跨膜结构、亲水/疏水性、功能位点、信号肽、序列同源性、糖基化和磷酸化位点、空间结构以及抗原表位进行分析。[结果]SM22-α蛋白编码201个氨基酸,为碱性蛋白,其等电点为8.85,不稳定指数为31.85,并将其归为稳定蛋白。其平均亲水系数为-0.607,为亲水性蛋白。根据IEDB在线软件发现SM22-α蛋白序列的第4-31、39-50、70-89、105-111、116-122、138-197存在B细胞抗原表位。利用HLA-A*0.2:0.1算法预测SM22-α蛋白序列第61和130位序列表面存在2个T细胞抗原表位;若利用HLA-DRBI*0401算法预测则第142位序列存在1个T细胞抗原表位。SM22-α蛋白的二级结构中α螺旋占46.77%,延伸链占6.47%,β-转角占4.48%,无规则卷曲占42.29%。且通过生物信息学分析可知SM22-α蛋白在不同物种之间的同源性为97.0%~68.7%。[结论]SM22-α为碱性、稳定、亲水性胞外蛋白,且蛋白表面含有T、B细胞抗原表位,可为其抗原性药物研究提供理论参考。     

合成多肽制备的抗体用于蛋白质免疫组织细胞化学定位研究

对本实验室克隆的小麦春化相关基因VER2编码蛋白的氨基酸序列进行软件分析,确定了具有免疫原性的一段（204～215位）含12个氨基酸的短肽,用化学法合成了该短肽并将其与牛血清白蛋白（BSA）相偶联,用偶联物作为抗原免疫家兔获得该12肽的抗体. 分别用VER2全蛋白抗体和该12肽抗体对VER2蛋白进行免疫细胞定位比较分析,两者所得结果一致,即二者在免疫组化检测蛋白质时的灵敏性和特异性方面具有一致的特性. 结果表明,化学法合成短肽制备的抗体可用于蛋白质的免疫组织细胞化学分析, 该方法快捷灵敏,且具有较高的特异性.     

尼帕病毒F糖蛋白在重组牛痘病毒中的表达及鉴定

尼帕病毒(NiV)F蛋白在病毒侵入细胞和诱导中和抗体等方面具有重要作用。通过over-lapping PCR合成密码子优化的F蛋白基因构建了表达NiV F蛋白的重组牛痘病毒(WR株)rWR-NiV-F。利用兔抗NiV血清为检测抗体,通过间接免疫荧光(IFA)检测到了F蛋白在重组病毒感染细胞中的表达。SDS-PAGE和Western blot检测证明重组蛋白F0被裂解为F1和F2。以rWR-NiV-F感染瞬时转染共表达NiV受体结合囊膜糖蛋白G的BHK细胞,可诱导细胞膜融合及合包体形成,证明该重组病毒表达F蛋白保持良好的抗原性及生物学活性,为NiV诊断及重组活载体疫苗研究奠定了重要基础。     

Isolation of a Fusion Protein Containing the Antigenic Domain 1 of Human Cytomegalovirus Glycoprotein B and its Application in ELISA Tests

The glycoprotein B (gB) of human cytomegalovirus represents a dominant antigen for the humoral immune response. The immunodominant region on gB is the antigenic domain 1 (AD-1), a complex structure that requires a minimal continuous sequence of more than 75 amino acids for antibody binding. In this study, this domain was expressed in Escherichia coli as a fusion protein with β-galactosidase but yielded insoluble protein aggregates as inclusion bodies. To recover the fusion protein, inclusion bodies were solubilized by two extractions with urea 8 m and the fusion protein then isolated using gel filtration chromatography. After confirmation of fusion protein antigenicity by Western blotting, the purified product was used as the capturing antigen in an enzyme-linked immunosorbent assay (ELISA) to determine the presence of viral antibodies in serum samples of pregnant women. A cut-off point of approximately 0.2 absorbance units could discriminate the results of seropositive from seronegative pregnant women. The data indicates the potential usefulness of the fusion protein for the development of immunoassay for detection of the HCMV antibodies. Received 22 September 2005; Revisions requested 10 October 2005; Revisions received 26 October 2005; Accepted 31 October 2005     

Expression of a human cytomegalovirus gp58 antigenic domain fused to the hepatitis B virus nucleocapsid protein

Abstract Hepatitis B virus core antigen (HBcAg) has been used as a carrier for expression and presentation of a variety of heterologous viral epitopes in particulate form. The aim of this study was to produce hybrid antigens comprising HBcAg and an immunogenic epitope of human cytomegalovirus (HCMV). A direct comparison was made of amino and carboxyl terminal fusions in order to investigate the influence of position of the foreign epitope on hybrid core particle formation, antigenicity and immunogenicity. HCMV DNA encoding a neutralising epitope of the surface glycoprotein gp58 was either inserted at the amino terminus or fused to the truncated carboxyl terminus of HBcAg and expressed in Escherichia coli . The carboxyl terminal fusion (HBc_3–144-HCMV) was expressed at high levels and assembled into core like particles resembling native HBcAg. Protein with a similar fusion at the amino terminus (HCMV-HBc_1–183) could not be purified or characterised immunologically, although it formed core like particles. HBc_3–144-HCMV displayed HBc antigenicity but HCMV antigenicity could not be detected by radioimmunoassay or western blotting using anti-HCMV monoclonal antibody 7–17 or an anti-HCMV human polyclonal antiserum. Following immunisation of rabbits with HBc_3–144-HCMV, a high titre of anti-HBc specific antibody was produced along with lower titres of HCMV/gp58 specific antibody.     

棉铃虫病毒gp41基因的克隆表达及抗体制备

根据棉铃虫单核衣壳核多角体病毒(Helicoverpa armigerasingle nucleocapsid nucleopolyhedrovirus,HaSNPV)gp41基因的序列,设计引物,引入适当的酶切位点,通过PCR的方法扩增目的片段。将扩增出的基因片段克隆至原核表达载体pET-28a,构建重组质粒并转化至大肠杆菌中,经IPTG诱导表达。纯化蛋白产物并免疫家兔产生抗血清。该抗血清可与原核表达的His-GP41融合蛋白及在感染的昆虫细胞中表达的GP41蛋白发生特异性免疫反应。该抗体的获得为深入研究GP41的功能提供了基础。     

Physical interaction between the herpes simplex virus type 1 immediate-early regulatory proteins ICP0 and ICP4.

The herpes simplex virus type 1 immediate-early protein ICP0 enhances expression of a spectrum of viral genes alone and synergistically with ICP4. To test whether ICP0 and ICP4 interact physically, we performed far-Western blotting analysis of proteins from mock-, wild-type-, and ICP4 mutant virus-infected cells with in vitro-synthesized [35S]Met-labeled ICP0 and ICP4 as probes. The ICP4 and ICP0 polypeptides synthesized in vitro exhibited molecular weights similar to those of their counterparts in herpes simplex virus type 1-infected cells, and the in vitro-synthesized ICP4 was able to bind to a probe containing the ICP4 consensus binding site. Far-Western blotting experiments demonstrated that ICP0 interacts directly and specifically with ICP4 and with itself. To further define the interaction between ICP0 and ICP4, we generated a set of glutathione S-transferase (GST)-ICP0 fusion proteins that contain GST and either ICP0 N-terminal amino acids 1 to 244 or 1 to 394 or C-terminal amino acids 395 to 616 or 395 to 775. Using GST-ICP0 fusion protein affinity chromatography and in vitro-synthesized [35S]Met-labeled ICP0 and ICP4, ICP4 was shown to interact preferentially with the fusion protein containing ICP0 C-terminal amino acids 395 to 775, whereas ICP0 interacted efficiently with both the N-terminal GST-ICP0 fusion proteins and the C-terminal GST-ICP0 fusion proteins containing amino acids 395 to 775. Fusion protein affinity chromatography also demonstrated that the C-terminal 235 amino acid residues of ICP4 are important for efficient interaction with ICP0. Collectively, these results reveal a direct and specific physical interaction between ICP0 and ICP4.     

Identification of sequences in herpes simplex virus type 1 ICP22 that influence RNA polymerase II modification and viral late gene expression

Previous studies have shown that the herpes simplex virus type 1 (HSV-1) immediate-early protein ICP22 alters the phosphorylation of the host cell RNA polymerase II (Pol II) during viral infection. In this study, we have engineered several ICP22 plasmid and virus mutants in order to map the ICP22 sequences that are involved in this function. We identify a region in the C-terminal half of ICP22 (residues 240 to 340) that is critical for Pol II modification and further show that the N-terminal half of the protein (residues 1 to 239) is not required. However, immunofluorescence analysis indicates that the N-terminal half of ICP22 is needed for its localization to nuclear body structures. These results demonstrate that ICP22's effects on Pol II do not require that it accumulate in nuclear bodies. As ICP22 is known to enhance viral late gene expression during infection of certain cultured cells, including human embryonic lung (HEL) cells, we used our engineered viral mutants to map this function of ICP22. It was found that mutations in both the N- and C-terminal halves of ICP22 result in similar defects in viral late gene expression and growth in HEL cells, despite having distinctly different effects on Pol II. Thus, our results genetically uncouple ICP22's effects on Pol II from its effects on viral late gene expression. This suggests that these two functions of ICP22 may be due to distinct activities of the protein.     

Antigenic modulation induced by monoclonal antibodies: antibodies to measles virus hemagglutinin alters expression of other viral polypeptides in infected cells

Polyclonal antibody to measles virus can have profound effects on external (outer plasma membrane) as well as internal (cytoplasmic) viral polypeptides expressed in infected cells. The process, termed "antibody-induced antigenic modulation," was further investigated by using monoclonal antibody to several viral polypeptides. Four monoclonal antibodies against the viral hemagglutinin had the ability to decrease the expression of the phosphoprotein, fusion, and membrane protein. A monoclonal antibody to the nucleocapsid protein did not cause these changes. The observed decreases were not due to preferential degradation of viral polypeptides as determined by pulse-chase experiments. Our results indicate that a specific signal to an epitope on the plasma membrane (monoclonal antibody measles virus hemagglutinin) can alter the expression of measles virus phosphoprotein and membrane protein, both polypeptides present in the cytoplasm of infected cells.