小反刍兽疫病毒H糖蛋白基因原核表达载体的构建及表达

参照GenBank中小反刍兽疫病毒（PPRV）H抗原基因序列，人工合成了PPRVH基因，将其克隆至PUC18-T质粒中，转化E．coli JM109感受态细胞，构建并选择PPRVH基因克隆重组质粒，经核苷酸序列分析正确，将其克隆至pBAD／Thio—TOPO载体中，转化E．coli TOP10感受态细胞，核苷酸序列分析证实，成功构建了PPRVH基因重组表达载体。经不同浓度L-阿拉伯糖诱导，可稳定、高效地表达PPRVH抗原。SDS-PAGE分析结果表明，用终浓度为0．2g／L的L-阿拉伯糖诱导5h的表达量最高，表达蛋白为分子质量约83ku的融合蛋白；经薄层扫描分析，其表达产量约占菌体总蛋白的10％。Western-blotting检测表明，诱导的蛋白能与PPRVH蛋白单抗发生特异性反应，说明表达的融合蛋白中含有PPRVH糖蛋白抗原。     

小反刍兽疫病毒H基因的原核表达与鉴定

根据GenBank中已发表的小反刍兽疫病毒(PPRV)Nigeria 75/1株的H基因序列,设计上下游引物并添加BamH I酶切位点,以含有小反刍兽疫病毒H基因的Topo-PPRVH质粒为模板进行PCR扩增,扩增产物克隆于pEASY-T载体中,用BamH I单酶切后将目的片段连接到原核表达载体pET-32a(+)中,核酸序列分析证明.成功构建了PPRV H原核表达质粒pET-32a-H.将pET-32a-H重组质粒转化大肠杆茵 BL21(DE3)进行融合表达.经SDS-PAGE电泳,可见H蛋白获得了高效表达,融合蛋白的分子量约为87 Ku,表达产物以包涵体的形式存在,其表达量达到茵体总蛋白的38%,占包涵体蛋白的80%以上.Western blot鉴定表明,所表达的重组蛋白能被抗组氨酸单抗、抗PPRV标准阳性羊血清及抗PPRV疫苗的羊血清所识别,具有良好的免疫原性.     

小反刍兽疫病毒N、H和F蛋白的真核表达

目的构建小反刍兽疫病毒(PPRV)H、N、F、NF重组真核表达质粒并观察其在真核细胞内的表达情况。方法采用逆转录聚合酶链式反应(RT-PCR)技术,从病羊组织中扩增PPRV的N、H、F基因序列并克隆到真核表达载体pIRES1neo中,最后用PCR、酶切和序列分析对重组质粒进行鉴定;将重组质粒以磷酸钙介导法转染Vero细胞,用免疫荧光方法鉴定其在细胞中的表达。结果将RT-PCR产物电泳,得到与预期大小相符的特异性片段;重组质粒经pIRES1-N、pIRES1-H、pIRES1-F和pIRES1NF酶切后,均出现预期相符的片段;DNA测序表明插入片段的序列与小反刍兽疫病毒N、H、F蛋白基因序列完全一致,其大小分别为1575bp、1830bp和1641bp;将重组质粒感染真核细胞,经免疫荧光检测,证明所有蛋白均得到表达。结论成功构建了重组真核表达质粒pIRES1-N、pIRES1-H、pIRES1-F和pIRES1NF,为继续进行基因免疫研究奠定了基础。     

小反刍兽疫病毒H基因在杆状病毒中的表达

从小反刍兽疫病毒全长cDNA中对血凝素蛋白H基因进行特异扩增,回收PCR产物分别连接于T载体酶切及测序分析后,将其亚克隆至真核表达转移载体pFastBacHT,经重组筛选获得杆状病毒重组质粒。重组质粒转染sf9细胞后连续传3～4代,分别收获细胞上清及沉淀用于SDS-PAGE及Western blot对重组H蛋白的检测,用抗His蛋白单抗在细胞中检测到H标签蛋白,单抗在细胞及上清中检测到大小为46 ku的融合蛋白。     

小反刍兽疫病毒N基因在昆虫细胞中的表达

为了研发小反刍兽疫病毒ELISA检测试剂盒中替代全病毒的抗原物质,参照GenBank公布的小反刍兽疫疫苗株Nigeria75/1的全基因组序列(GenBank登录号:X74443),人工合成表达核蛋白的N基因开放阅读框序列,通过PCR扩增、经引物设计引入的EcoRⅠ和KpnⅠ特异性酶切位点,将N基因克隆于昆虫杆状病毒表...     

小反刍兽疫病毒N基因的原核表达

目的是表达出小反刍兽疫病毒的核蛋白,并鉴定其活性.根据GenBank发表的小反刍兽疫病毒(PPRV)Nigeria 75/1株N基因序列,对其进行基因优化并合成.设计引物,利用PCR的方法扩增PPRV-N基因,将该基因片段定向克隆到原核表达载体pET-28a(+)中,构建原核表达栽体pET-28a-N.阳性质粒转化原核...     

小反刍兽疫病毒H蛋白的原核表达和免疫学活性鉴定

研究小反刍兽疫病毒（Peste des petits ruminants virus,PPRV）H 蛋白生物学活性,为建立PPRV 抗体检测方法提供材料。根据 GenBank 已发表的 PPRV H 蛋白质序列,设计上、下游引物,以 PPRV核酸为模板进行 PCR 扩增,扩增产物克隆至 pET52／LIC 载体中,构建了 pET52／LIC-PPRV H 表达载体。将 pET52／LIC-PPRV H 重组质粒转化大肠埃希菌 BL21（DE3）进行融合表达,经 SDS-PAGE 电泳分析,可见 PPRV H 蛋白成功得到了表达,融合蛋白的分子质量约为75 ku,Western blot 分析表明所表达的重组蛋白可与 PPRV 阳性血清发生特异性反应,说明表达的 PPRV H 蛋白可以作为建立 PPRV 抗体检测的蛋白。     

小反刍兽疫病毒M基因截短表达及鉴定

目的将小反刍兽疫病毒M蛋白基因截短表达后用于特异性单抗制备及临床抗体水平检测。方法:用在线分析软件BepiPred分析小反刍兽疫病毒M蛋白潜在的B细胞线性表位,以本实验室构建的pCR2.1T-PPRV M质粒为模板,扩增三段截短的M基因,纯化后的PCR产物分别与克隆载体pCR2.1T连接,筛选出的阳性重组质粒经双酶切后,分别与表达载体pET-32a(+)及pGEX-6p-1连接,再将鉴定为阳性的重组质粒转化入E.coli BL21(DE3)菌株诱导表达,并用SDS-PAGE及Western blot验证。结果 PCR产物电泳,得到与预期大小相符的特异性片段。对连接克隆载体及表达载体的重组质粒双酶切后,均出现与预期一致的片段,DNA测序表明,插入片段序列与小反刍兽疫Nigeria75/1株M蛋白基因完全一致。重组蛋白经SDS-PAGE及Western blot鉴定,证明所构建的重组蛋白均获得高效表达,并均具有良好的反应原性。结论成功表达了小反刍兽疫截短M基因的蛋白,为制备特异性单抗及小反刍兽疫抗体检测奠定了一定基础。     

携带小反刍兽疫病毒H基因的重组山羊痘病毒构建和鉴定

将小反刍兽疫病(PPRV)毒糖蛋白基因H插入到山羊痘病(GPV)毒通用转移载体PtkPgpt-egfpP启动子P7.5的下游,构建了重组山羊痘病毒转移载体PtkPgpt-egfpPpprv-H。该重组转移载体转染感染山羊痘病毒疫苗株的绵羊睾丸细胞中,通过同源重组获得小反刍兽疫病毒H基因重组山羊痘病毒,通过纯化和PCR鉴定,证明小反刍兽疫病毒H基因插入到山羊痘病毒基因组中。本研究为进一步研究PPRVH基因重组山羊痘病毒的免疫原性奠定了基础。     

小反刍兽疫病毒分子生物学研究进展

小反刍兽疫是一种急性、热性、接触性传染病,是世界动物卫生组织规定的A类传染病,在我国被列为一类动物疫病,具有高发病率和高死亡率等特点。该病给小反刍动物养殖及国家和外贸经济带来了巨大的损失。文章主要叙述了小反刍兽疫病毒各基因结构特点,6种结构蛋白的功能,小反刍兽疫的诊断技术等方面的最新研究进展。     

小反刍兽疫活疫苗的安全性评价试验

2007年小反刍兽疫(PPR)在我国西藏首次暴发,在西藏和新疆部分地区使用PPR Nigeria 75/1疫苗株制造的疫苗进行免疫接种。为明确疫苗的安全性,中国兽医药品监察所国家牛瘟参考实验室对其安全性能进行了系统评价。健康易感山羊、绵羊及怀孕山羊、怀孕绵羊按不同剂量接种疫苗后,均未观察到异常临床反应;怀孕母羊所产羔羊数量与对照组无明显差异。疫苗对小白鼠、豚鼠的非特异性安全试验表明,所有接种动物均健活。结果表明该疫苗安全性良好,可在田间大规模使用。     

小反刍兽疫疫苗毒与野毒实时荧光RT—PCR鉴别检测方法的建立

为了建立鉴别检测小反刍兽疫疫苗毒与野毒的快速分子生物学检测方法,通过对自行测序的疫苗毒基因组序列及GenBank中登录的野毒基因组序列进行比对分析,设计了2套引物和TaqMan荧光探针,对实时荧光RT-PCR反应条件进行优化,建立了小反刍兽疫疫苗毒与野毒实时荧光RT-PCR鉴别检测方法。特异性试验证实,该检测方法只能检测到目的病毒核酸,表明其具有良好的特异性。灵敏性试验发现,检测疫苗株的最低检测限可达1．38mg／L的总RNA,检测野毒株的最低检测限为0．16mg／L的核酸。对同一样品进行重复性检测,检测的荧光扩增曲线阈值完全重舍,证明其重复性极好。从180份临床样品中,检测出2份疫苗病毒株阳性样品,其余均为阴性。结果表明,本研究所建立的实时荧光RT-PCR方法能对小反刍兽疫疫苗毒及野毒进行鉴别检测,具有特异性好、灵敏度高、重复性极好的优点,是开展小反刍兽疫疫情监测的有力工具。     

辽宁省小反刍兽疫疫苗临床免疫效果跟踪试验及抗体水平动态观察

通过抽检小反刍兽疫疫苗免疫后的部分羊群,分别于免疫后的7、14、21、28 d对免疫羊进行抗体及病毒核酸（包括疫苗毒）跟踪监测,并对监测数据进行整理比对分析,继而掌握小反刍兽疫免疫抗体在机体内的消长规律及影响因素,进一步了解该疫苗辽宁省羊群中的免疫效果及安全性。结果表明,该疫苗在免疫7d后,免疫群体均能够达到免疫合格率高于70%的标准,且未出现疫苗排毒现象,证明该疫苗的免疫效果确实、安全性好。     

小反刍兽疫研究进展

小反刍兽疫(PPR)是由小反刍兽疫病毒(PPRV)引起的急性或亚急性传染病,为世界动物卫生组织(OIE)法定报告的动物疫病,易感动物以山羊、绵羊等小反刍动物为主。目前,小反刍兽疫主要流行于西非、中非、中东、阿拉伯半岛及南亚等地区。敏感特异的检测方法和高效的预防性疫苗将为该病的防控奠定良好的基础。论文对小反刍兽疫全球流行现状、诊断技术及疫苗研究进展进行了综述。     

小反刍兽疫病毒RT-LAMP检测方法的建立

利用逆转录环介导等温核酸扩增技术(RT-LAMP)建立了小反刍兽疫病毒快速检测方法,同时评价了该方法的灵敏性和特异性。结果表明,根据小反刍兽疫病毒N基因保守区域设计的LAMP引物能够在63℃恒温下,1小时内实现目的核酸的大量扩增,由于在检测前加入荧光指示试剂,检测结果可以直接用肉眼判断,避免了由于开盖检验带来的扩增产物污染导致的假阳性。该检测体系具有较高的特异性,只能特异性地检测目的病毒,与其他同属的病毒或类似病毒等无交叉反应;具有较高的检测灵敏度,比普通RT-PCR灵敏性高10倍,与荧光RT-PCR的灵敏度相当。     

Selection and identification of single-domain antibody against Peste des Petits Ruminants virus

BackgroundPeste des petits ruminants (PPR) is an infectious disease caused by the peste des petits ruminants virus (PPRV) that mainly produces respiratory symptoms in affected animals, resulting in great losses in the world''s agriculture industry every year. Single-domain variable heavy chain (VHH) antibody fragments, also referred to as nanobodies, have high expression yields and other advantages including ease of purification and high solubility.ObjectivesThe purpose of this study is to obtain a single-domain antibody with good reactivity and high specificity against PPRV.MethodsA VHH cDNA library was established by immunizing camels with PPRV vaccine, and the capacity and diversity of the library were examined. Four PPRV VHHs were selected, and the biological activity and antigen-binding capacity of the four VHHs were identified by western blot, indirect immunofluorescence, and enzyme-linked immunosorbent assay (ELISA) analyses. ELISA was used to identify whether the four VHHs were specific for PPRV, and VHH neutralization tests were carried out. ELISA and western blot analyses were used to identify which PPRV protein was targeted by VHH2.ResultsThe PPRV cDNA library was constructed successfully. The library capacity was greater than 2.0 × 10⁶ cfu/mL, and the inserted fragment size was approximately 400 bp to 2000 bp. The average length of the cDNA library fragment was about 1000 bp, and the recombination rate was approximately 100%. Four single-domain antibody sequences were selected, and proteins expressed in the supernatant were obtained. The four VHHs were shown to have biological activity, close affinity to PPRV, and no cross-reaction with common sheep diseases. All four VHHs had neutralization activity, and VHH2 was specific to the PPRV M protein.ConclusionsThe results of this preliminary research of PPRV VHHs showed that four screened VHH antibodies could be useful in future applications. This study provided new materials for inclusion in PPRV research.     

Post-vaccination antibodies profile against Peste des petits ruminants (PPR) virus in sheep and goats of Punjab,Pakistan

A total of 70 sheep and 330 goats were selected randomly. All the animals were kept under same housing and management conditions. Serum samples were collected from all the animals and tested for the presence of antibodies against Peste des petits ruminants (PPR) virus using competitive ELISA (cELISA). All the animals were found negative showing percentage inhibition (PI) values <50. The animals were vaccinated against PPR with Nig/75/1 strain vaccine of PPR Serum samples were collected from randomly selected 12 sheep and 30 goats at 10, 30 and 45 days post-vaccination. The samples were subjected to cELISA to determine the presence of antibodies against PPRV. The samples with PI >50 were considered as sero-positive. The sheep found positive at 10, 30 and 45 days post-vaccination were 1(8.3%), 7(58.3%) and 12(100%) respectively. In case of goats 3(10.0%), 29(96.6%) and 27(90.0%) animals gave positive results at 10, 30 and 45 days post-vaccination respectively. Mean PI values in sheep at 10, 30 and 45 days post-vaccination were recorded as 37, 65 and 91 respectively, whereas in goats these values were 43, 78 and 86 respectively.     

Fine mapping and conservation analysis of linear B-cell epitopes of peste des petits ruminants virus nucleoprotein

Nucleoprotein (NP) is the most abundant and highly immunogenic protein of morbillivirus, and is presently the basis of most diagnostic assays for peste des petits ruminants virus (PPRV). In this study, fine epitope mapping and conservation analysis of linear B-cell epitopes on the PPRV NP has been undertaken using biosynthetic peptides. Nineteen linear B-cell epitopes were identified and their corresponding minimal motifs were located on the NP of PPRV China/Tibet/Geg/07-30. Conservation analysis indicated that ten of the 19 minimal motifs were conserved among 46 PPRV strains. Peptides containing the minimal motifs were recognized using anti-PPRV serum from a goat immunized with PPRV vaccine strain Nigeria 75/1. Identified epitopes and their motifs improve our understanding of the antigenic characteristics of PPRV NP and provide a basis for the development of epitope-based diagnostic assays.