AsiaⅠ口蹄疫病毒VP1蛋白单克隆抗体的制备与鉴定

目的:制备AsiaI口蹄疫病毒VP1蛋白单克隆抗体(mAb)并进行鉴定。方法:用纯化的AsiaI型口蹄疫病毒VP1表位重组蛋白为抗原免疫6～8周龄的雌性BALB/c小鼠,经过3次免疫后,取其脾细胞与Sp2/0骨髓瘤细胞融合。采用有限稀释法和间接ELISA克隆和筛选阳性杂交瘤细胞株,用SDS-PAGE电泳、间接ELISA以及微量细胞中和试验对所获得的mAb的特异性进行鉴定。结果:成功获得3株能稳定传代并分泌抗AsiaImAb的杂交瘤细胞株,分别命名为:1B8、5E1、5E2,其分泌的mAb为IgG1(1B8)和IgG2a(5E1、5E2)亚类,他们均能特异性的识别VP1重组蛋白和AsiaI型全病毒,其腹水效价在1:105～1:106。微量细胞中和试验表明该mAb能很好地识别灭活的FMDV,中和效价达1:1024以上。交叉试验表明该mAb具有高度特异性,型间无交叉反应,证明所获得的mAb均完全针对AsiaI FMDV抗原决定簇。结论:在口蹄疫病毒mAb的研究中,VP1重组蛋白有望代替活病毒来制备mAb。AsiaI口蹄疫病毒VP1mAb的成功制备,为进一步研究和开发新型口蹄疫的检测方法和抗原表位奠定了基础。     

抗O型口蹄疫病毒VP1单克隆抗体的制备与鉴定

目的：制备抗O型口蹄疫病毒（FMDV）衣壳蛋白VP1的单克隆抗体（mAb）并进行特性鉴定。方法：以自行构建表达的O型FMDV—VP1表位重组蛋白（VP1epi）为抗原免疫BALB／c小鼠，按常规方法进行细胞融合。采用有限稀释法和间接ELISA法克隆和筛选阳性杂交瘤细胞株，用Western blot、间接ELISA和斑点免疫测定法对mAb的特异性进行鉴定。结果：成功地获得1株分泌抗VPlepi重组蛋白mAb的杂交瘤细胞株“C7”，其分泌的mAb为IgG1亚类，能特异性地识别VP1epi重组蛋白，其腹水效价可达1：12800。斑点免疫测定法显示，该mAb能很好地识别灭活的FMDV。结论：VP1epi重组蛋白可代替FMDV制备抗天然FMDV—VP1的mAb。抗O型FMDV—VP1 mAb的成功制备，为进一步研究开发新型FMDV的检测方法奠定了基础。     

EV71结构蛋白VP1的原核表达及VP1单克隆抗体的制备

目的:原核表达EV71结构蛋白VP1并制备其单克隆抗体。方法:以肠道病毒71型(EV71)P1基因为模板,设计引物扩增出目的片段VP1,将其连接至大肠杆菌表达载体pET-32a(+)上,转化大肠杆菌TG1,筛选出阳性克隆后进行测序。将重组表达载体pET-32a(+)-VP1转化大肠杆菌表达菌株BLgold(DE3),对该工程菌进行诱导表达,SDS-PAGE电泳分析,表达产物以包涵体的形式存在。包涵体用6 mol/L盐酸胍溶解,经过Ni-NTA亲和层析法纯化,获得了纯度较高的目的蛋白。用纯化的VP1蛋白免疫小鼠,制备单克隆抗体(mAb)。结果:获得了24株mAb,其中1株EV71 Westernblot法鉴定呈阳性,5株EV71间接免疫荧光法(IFA)鉴定阳性。结论:成功地制备了VP1的mAb。     

肠道病毒71型外壳蛋白VP1的可溶性表达、纯化及活性鉴定

目的克隆、表达和鉴定肠道病毒71型（EV71）VP1基因,得到可溶性的蛋白VP1,为制备EV71的抗体和诊断试剂的开发打下基础。方法优化EV71VP1蛋白基因,克隆并构建重组表达质粒pET15b/VP1,转化大肠杆菌BL21。使用Ni2＋亲和层析柱对重组蛋白进行纯化,并用Westernblotting检测目的蛋白。以重组蛋白VP1为抗原,ELISA检测抗原活性。结果重组蛋白在大肠杆菌中可以高效表达,SDS-PAGE显示其相对分子质量为36000,与预计大小一致。ELISA实验证实,重组蛋白具有良好的抗原性。结论本研究成功克隆和表达了EV71VP1蛋白,并得到可溶性的蛋白,对肠道病毒71型诊断试剂的开发有进一步潜在的应用价值。     

PC-1蛋白单克隆抗体制备和鉴定

为获得高效价PC-1蛋白的鼠单克隆抗体(mAb),用于PC-1功能的实验,采用纯化的PC-1蛋白与GST的融合蛋白(GST-PC-1)为抗原,免疫小鼠和骨髓瘤细胞进行细胞融合,用直接ELISA法进行克隆化筛选,mAb的染色体分析及亚类鉴定及初步应用.结果表明细胞融合和ELISA筛选后,获得2株抗鼠PC.1蛋白mAb,两株PC-1 mAb效价分别为1:25600,1:13600,抗体亚型为IgG1,Western blot证实其特异性识别PC-1蛋白.该mAb可以用于测定PC-1蛋白.     

口蹄疫病毒非结构蛋白3D单克隆抗体的制备及鉴定

目的:制备并鉴定口蹄疫病毒(FMDV)非结构蛋白3D的单克隆抗体(mAb).方法:以纯化的原核表达3D蛋白免疫BALB/c小鼠, 取其脾细胞与小鼠骨髓瘤细胞融合, 杂交瘤细胞经间接ELISA法筛选, 有限稀释法克隆, 直至所克隆的细胞能够100%的分泌抗体, 用Western blot以及间接免疫荧光法对mAbs的特异性等进行鉴定.结果:免疫的BALB/c小鼠经过多次融合筛选, 共获得5株抗pET28a-3D的mAb, 其亚类鉴定3株为IgG1 , 2株为IgG2b, 初步判定所得5株mAb识别2个不同表位.Western blot显示这些mAbs与重组3D蛋白和FMDV O/China99感染的BHK-21细胞中的3D抗原均特异性结合, 免疫荧光结果显示这5株mAb能够特异结合FMDV感染细胞中的3D蛋白.结论:成功获得了能识别自然3D蛋白的特异性mAb , 为进一步研究3D蛋白的结构和功能以及诊断方法奠定基础.     

西尼罗病毒NS1蛋白特异性单克隆抗体的制备与鉴定

目的:制备针对西尼罗病毒NS1蛋白的特异性单克隆抗体。方法:以原核表达的重组NS1蛋白为免疫原,免疫BALB/c小鼠并通过常规杂交瘤技术将免疫后小鼠脾细胞与SP2/0细胞进行融合。以真核表达的重组NS1蛋白为检测用抗原,建立间接ELISA检测方法筛选分泌NS1蛋白单克隆抗体的杂交瘤细胞。并利用Western blot和IFA试验对所获得的单克隆抗体进行鉴定。结果:共获得了2株稳定分泌NS1蛋白单克隆抗体的杂交瘤细胞株,分别命名为WN-1C10和WN-3D10,其亚类鉴定分别属于IgG2a和IgG1。这2株单克隆抗体均能与西尼罗病毒NS1蛋白和病毒抗原发生特异性反应,而与日本脑炎病毒无交叉反应。结论:本实验成功制备出针对西尼罗病毒NS1蛋白的特异性单克隆抗体,为我国建立西尼罗病毒与日本脑炎病毒的血清学鉴别诊断方法奠定了基础。     

人类微小病毒B19结构蛋白VP2的重组表达及单克隆抗体的制备

目的：制备特异性的抗人类微小病毒B19单克隆抗体（mAb）杂交瘤。方法：采用PCR从B19病毒感染患者的血清标本中扩增编码VP2蛋白的基因，经克隆、测序确认后，再分别亚克隆至原核表达载体和真核表达载体。以从SDS-PAGE凝胶中回收的原核表达产物免疫BALB／c小鼠，制备可分泌特异性B19 mAb的杂交瘤细胞。以真核表达载体转染CHO细胞后，筛选单细胞表达克隆，将真核表达产物与用原核表达产物为免疫原制备的mAb反应。结果：从患者血清标本中扩增出了1665bp长的DNA，测序结果证实为vp2基因。将该基因克隆至原核表达载体中后，在大肠杆菌中获得了表达。表达产物经SDS-PAGE后，在Mr约为6000处可见1条明显的表达带。Western blot的结果表明，该电泳带与B19患者的血清呈特异性免疫反应。以从SDS-PAGE凝胶中回收的表达产物为免疫原，免疫BALB／c小鼠，经细胞融合、克降化，获得2株分泌特异性的抗VP2 mAb的杂交瘤细胞。以这2株杂交瘤细胞制备的腹水可与SDS-PAGE凝胶Mr6000的蛋白条带也出现很强的免疫反应。用ELISA证明以Vp2基因真核表达载体转染的CHO培养上清，也与筛选到的mAb呈阳性反应。结论：成功地制备抗VP2的mAb，为进一步研制可用于B19病毒感染早期免疫诊断试剂盒奠定了基础。     

建立一种用重组蛋白检测抗口蹄疫病毒抗体的间接ELISA方法

目的研究以重组蛋白作为包被抗原检测口蹄疫病毒（FMDV）感染后的动物血清中特异性抗体的可能性,为建立一种非病毒颗粒的ELISA检测试剂盒提供实验依据。方法利用自行构建表达的O型口蹄疫病毒VP1表位肽重组蛋白（VP1epi）作为包被抗原,采用间接ELISA方法确定抗原的最佳工作浓度和包被方法,优化各项实验条件,并以FMDV感染后的豚鼠血清作为标准阳性血清确定ELISA方法的特异性和灵敏度。结果FMDV感染后的阳性豚鼠血清可以很好地识别VP1epi重组蛋白,用此蛋白包被检测抗FMDV抗体的灵敏度可达1∶3200,并证明所检测的抗体是FMDV特异性的。结论VP1epi重组蛋白可以替代FMDV颗粒用于建立检测抗FMDV抗体的ELISA试剂盒。     

SAT2型口蹄疫病毒南非地区分离株结构蛋白VP1及其C端的表达、纯化和反应原性分析

目的:表达SAT2型口蹄疫病毒结构蛋白VP1及其C端,进行反应原性分析并制备多克隆抗体。方法:以SAT2型口蹄疫病毒南非地区分离株结构蛋白VP1编码区的重组克隆载体为模板,设计特异性引物,扩增VP1基因及其C端编码区,然后将该其分别克隆至原核表达载体pET-30a(+)中,转化大肠杆菌工程菌株BL21(DE3)plysS,经IPTG诱导,以金属离子螯合层析法对表达的VP1、VP1C端融合蛋白进行纯化,经Westernblot对其反应原性进行分析。用纯化的蛋白免疫新西兰大耳白兔制备其多克隆抗体,以ELISA方法测定抗体效价。结果:实现了SAT2型口蹄疫病毒结构蛋白VP1及其C端的高效表达,表达产物主要以包涵体的形式存在。SDS-PAGE显示纯化的目的蛋白分别在相对分子质量35000和19000处有单一目的条带,具有较高的纯度。Westernblot结果显示,纯化的VP1及其C端均可与牛SAT2型FMDV阳性血清反应,而与阴性对照血清无交叉反应。结论:用纯化的VP1及VP1C融合蛋白免疫新西兰大耳白兔制备的多克隆抗体效价达1∶12800以上,具有较高的特异性。     

Sequences of capsid protein VP1 of two type a foot-and-mouth disease viruses

We have sequenced the nucleotides of the regions that encode the capsid protein VP1 of the foot-and-mouth disease viruses (FMDV) A₅Bernbeuren/1984 and A Iran/1987. Amino acid sequences and secondary protein structures are provided. Both proteins consist of 212 amino acids. The sequences and secondary structures are compared to those of FMDV A₂₂/CCCP/64, a strain previously endemic in the Near East. Nucleotide divergency among the three sequences is highest for FMDV A₅Bernbeuren/1984 (18% compared to 13% for each other case). Thirty amino acid divergencies are observed between A₂₂/CCCP/64 and A₅ Bernbeuren/1984 or A Iran/1987, whereas the latter two differ by 27 residues. The secondary structures of all three proteins are different. A Iran/1987 is considered to belong to a thus far unknown subtype.     

Partial sequence analysis of VP1 of Indian isolates of foot-and-mouth disease virus type Asia-1

Nucleotide sequence of 3' end of VP1 (1D region) was determined using RT-PCR amplified DNA of 31 foot and mouth disease virus (FMDV) type Asia-1 field isolates originating from 11 different geographically distinct states of India during the period 1987-2000. These field strains exhibited an average of 7.5% divergence among them and were found to be divergent from the Indian vaccine strains Asia-1 WBN 117/85, IND 8/79, and IND 63/72, by an average 5.9, 14.8, and 7.4% divergence, respectively. Phylogenetic analysis of these 31 field isolates including 3 of the vaccine strains of India and sequences of 22 Indian field isolates obtained from the GenBank revealed that all the Indian FMDV type Asia-1 isolates belonged to a single genotype comprising of two distinct lineages (Lineages A and B). All the field isolates under study belonged to the Lineage-B comprising 8 different clusters, which also includes the vaccine strains WBN-117/85 and IND 8/79. Surprisingly, another vaccine strain IND 63/72 formed Lineage-A. Phylogenetic analysis of sequences of another 23 exotic type Asia-1 isolates from 15 different countries obtained from the GenBank along with the 56 Indian isolates revealed the existence of three distinct genotypes. The prototype strain Asia-1 PAK 1/54 belongs to a separate genotype. Two strains from India along with one strain each from China and Russia belongs to another genotype. The third genotype is formed by the remaining isolates including all the 31 isolates from the present study and exotic viruses from 14 other different countries. Comparison of deduced amino acid (aa) sequence indicated that majority of the mutations were found within two distinct regions corresponding to amino acid positions 130-160 and 193-211. The motif at aa positions 138-141 in vaccine strains WBN 117/85, IND 8/79 and in all the field isolates was ETTS/P; however, the same motif in IND 63/72 was TQPT. The motif 153-156 in majority of Indian isolates including vaccine strains WBN 117/85 and IND 8/79 was LSGQ/R whereas the same motif seen in IND 63/72 was VSNR. The study revealed that the FMDV type Asia-1 isolates circulating in the country are not highly heterogeneous, but showed considerable genetic variations. Certain mutations were also observed in the residues, which have been proved to be contributing to the formation of neutralizing epitopes. In neutralization studies employing polyclonal antisera, type Asia-1 WBN 117/85 revealed broader serological spectrum than other vaccine strains of India used in this study.     

抗MDV-1 VP22羧基端单克隆抗体的制备与免疫学特性鉴定

目的：制备抗血清Ⅰ型马立克氏病病毒（MDV-1）VP22的单克隆抗体（mAb），并鉴定其免疫学特性。方法：在原核系统中表达VP22羧基端区域（94～243aa），获得融合表达产物GST-VP22C。将该表达产物切胶免疫小鼠，利用杂交瘤技术制备抗MDV-1VP22C的mAb，并通过ELISA、间接免疫荧光（IFA）、Western blot鉴定其特性。结果：获得了2株可稳定分泌抗MDV-1VP22C的mAb的杂交瘤细胞，命名为3F7、4FA。IFA鉴定表明，两株mAb均能与感染MDV-1的成纤维细胞反应，其中，3F7mAb染色呈现MDV空斑，而4FAmAb呈现整个单层的细胞核荧光。ELISA和Westernblot分析表明，3F7能与杆状病毒表达的VP22反应，4FA不具备该特性。对3F7mAb进一步鉴定，确定了该mAb针对的具体位置在94～193aa处，是蛋白转导域的预测位置。结论：成功地制备了抗MDV-1VP22C的mAb，为深入研究VP22蛋白的转导功能提供了有用的试剂。     

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。     

抗Ⅳ型登革病毒NS1单克隆抗体的制备及特性鉴定

目的:研制Ⅳ型登革病毒(DENV-4)非结构蛋白1(NS1)特异性的单克隆抗体(mAbs),并鉴定其特异性。方法:在表达具有良好抗原性的重组DENV4-NS1蛋白的基础上,用重组DENV4-NS1蛋白和灭活的DENV-4免疫BALB/c小鼠,取免疫小鼠的脾细胞与小鼠骨髓瘤细胞进行融合,用间接ELISA法筛选阳性的杂交瘤细胞,并结合免疫荧光测定法(IFA)和Western blot分析对mAb的特异性进行鉴定;通过竞争抑制试验对mAb识别的抗原位点进行分析。结果:获得15株特异性针对DENV4-NS1的mAbs,与其他3型DENV的NS1不产生交叉反应。mAb的Ig亚类测定均为IgG1。竞争抑制试验显示,15株mAbs存在2个不同识别抗原位点。结论:成功地获得特异性针对DENV4-NS1蛋白的mAbs,为进一步研究DENV4-NS1蛋白的结构与功能及研制DENV-4的临床诊断试剂奠定了基础。     

Immunization of DNA vaccine encoding C3d-VP1 fusion enhanced protective immune response against foot-and-mouth disease virus

Because foot-and-mouth disease virus (FMDV) remains a great problem to many livestock of agricultural importance, safe, effective vaccines are in great need. DNA vaccine would be a promising candidate but the design remains to be optimized. VP1 gene of FMDV strain O/ES/2001 was linked to three copies of either porcine or murine C3d or four copies of a 28-aa fragment of murine C3d containing the CR2 receptor binding domain (M28). The resultant plasmids encoding C3d/M28-VP1 fusion or only VP1 as control were immunized guinea pigs. Both cellular and humoral immune responses were evaluated and protection was observed after virus challenge. As a result, although the plasmid encoding only VP1 could elicit virus-binding antibody detected by ELISA, splenocyte proliferation, IL-4 and IFN-γ production, the levels were significantly less than C3d/M28-VP1 fusion. Furthermore, VP1 failed to induce neutralization antibody and protect animals against virus challenge, while murine C3d-VP1 fusion efficiently induced neutralization antibody response and provided 87.50% of the animals with complete protection and 12.50% with partial protection. Among murine C3d, M28, and porcine C3d, the adjuvant effect of murine C3d is strongest, followed by porcine C3d, and last murine M28. In conclusion, the fact that C3d genes, when coupled to VP1 gene, are able to greatly enhance the protective immune response of VP1 DNA in guinea pigs suggests that C3d-VP1 DNA chimera has a significant potential for use as a novel DNA vaccine against FMDV.     

Role of arginine-56 within the structural protein VP3 of foot-and-mouth disease virus (FMDV) O1 Campos in virus virulence

FMDV O1 subtype undergoes antigenic variation under diverse growth conditions. Of particular interest is the amino acid variation observed at position 56 within the structural protein VP3. Selective pressures influence whether histidine (H) or arginine (R) is present at this position, ultimately influencing in vitro plaque morphology and in vivo pathogenesis in cattle. Using reverse genetics techniques, we have constructed FMDV type O1 Campos variants differing only at VP3 position 56, possessing either an H or R (O1Ca-VP3-56H and O1Ca-VP3-56R, respectively), and characterized their in vitro phenotype and virulence in the natural host. Both viruses showed similar growth kinetics in vitro. Conversely, they had distinct temperature-sensitivity (ts) and displayed significantly different pathogenic profiles in cattle and swine. O1Ca-VP3-56H was thermo stable and induced typical clinical signs of FMD, whereas O1Ca-VP3-56R presented a ts phenotype and was nonpathogenic unless VP3 position 56 reverted in vivo to either H or cysteine (C).     

抗ARL-1单克隆抗体的制备及初步应用

目的: 制备抗醛糖还原酶相似蛋白(aldosereductaselikeprotein, ARL- 1)的单克隆抗体 (mAb)并进行初步应用。方法: 用纯化的ARL- GST蛋白免疫BALB/c小鼠, 采用杂交瘤技术制备mAb。间接ELISA法、Westernblot及免疫组织化学染色法, 对mAb进行鉴定及初步应用。结果: 获得 1株可稳定分泌抗ARL -1蛋白mAb的杂交瘤细胞系。mAb的Ig亚类为IgG2b, 轻链属于κ型。腹水mAb的效价为: 1∶4. 096×105。Westernblot的结果表明, ARL 1蛋白在被检测的肝癌组织中呈高表达, 而在相应的癌旁组织中不表达。免疫组织化学染色的结果表明, ARL -1蛋白在肝癌组织中呈高表达且主要定位在胞质内。结论: 成功地制备 1株抗ARL -1蛋白的mAb。初步应用的结果表明, ARL- 1蛋白在肝癌组织中呈高表达, 为进一步研究ARL -1蛋白的功能, 以及其与肝癌的确切关系奠定了基础。     

免疫途径和佐剂对CVB3VP1蛋白免疫效果的影响

目的:观察不同免疫途径和佐剂类型对柯萨奇病毒B组3型(Coxsackievirus group B type 3,CVB3)衣壳蛋白VP1免疫效果的影响.方法:将原核表达质粒pET-his/VP1转入E.coli BL21 (DE3) pLysS中,用异丙基-1-硫代-β呋喃半乳糖苷(IPTG)诱导CVB3VP1蛋白的表达并进行纯化.首先采用不同的免疫途径(皮下,腹腔,肌肉)用VP1蛋白免疫小鼠,每组12只.然后另取小鼠分为PBS组和不同佐剂组(氢氧化铝、弗氏佐剂、Montanide ISA720),每组18只,采用肌肉注射途径免疫.每次每只小鼠注射50μg,共免疫3次,间隔3周.用ELISA和微量中和试验检测血清特异性IgG抗体和中和抗体.用CCK-8法检测淋巴细胞增殖活性和CTL杀伤活性.用致死量的CVB3攻击后,检测血中病毒的滴度并观察小鼠的存活状况.结果:在大肠杆菌中成功表达CVB3VP1蛋白.三种免疫途径比较,肌肉注射组血清中和抗体和特异性IgG抗体的水平明显高于其他组(P＜0.01).采用肌肉注射免疫时,弗氏佐剂组Montanide ISA 720佐剂组的体液免疫和细胞免疫应答的水平明显高于氢氧化铝组(P＜0.05);但血中病毒的滴度低于氢氧化铝组(P＜0.05).弗氏佐剂组小鼠的生存率好于氢氧化铝组(P＜0.05).结论:采用肌肉注射途径,并联合弗氏佐剂或Montanide ISA 720佐剂可以使CVB3VP1免疫获得较好的免疫效果.