普氏立克次体120kDa表面抗原C段基因的克隆与表达

采用PCR方法 ,从普氏立克次体基因组中扩增出 1 2 0kDa表面抗原C段基因片断 ,并将其克隆于原核表达载体pQE30 ,构建重组质粒pQE30 6 7,将重组质粒转入大肠杆菌M1 5 ,用IPTG诱导大肠杆菌内的目的基因表达。SDS PAGE分析发现重组质粒转化菌产生了一 6 7kDa重组蛋白 ;在免疫印迹分析中 ,该 6 7kDa重组蛋白与普氏立克次体免疫血清发生特异反应 ,显示 6 7kDa重组蛋白具有普氏立克次体 1 2 0kDa表面抗原特性     

恙虫病东方体Sta56抗原的原核表达、纯化及其在间接ELISA中的应用

目的　构建含恙虫病东方体sta5 6基因的重组表达质粒 ,在E .coli中表达Sta5 6重组抗原 ,纯化后用于间接ELISA检测恙虫病。方法　从含有恙虫病东方体Karp株sta5 6基因的重组质粒TOPO sta5 6扩增出截短的sta5 6 ,定向插入pET30a载体 ,转化大肠杆菌BL2 1(DE3) ,IPTG诱导表达 ,用SDS PAGE及Westernblot进行分析 ;采用电洗脱方法纯化重组抗原并应用于间接ELISA检测恙虫病。结果　以截短的sta5 6基因片段构建了重组表达质粒pETOt95 7,重组的Sta5 6抗原可在E .coli中以融合蛋白的形式有效表达 ,SDS PAGE显示了一条相对分子质量 (Mr)为 4 0 .3× 10 3 的蛋白表达带 ,West ernblot证实该融合蛋白能被恙虫病患者阳性血清所识别。电洗脱纯化的重组抗原应用于间接法ELISA检测恙虫病 ,与间接免疫荧光法IFAT比较 ,其敏感性和特异性分别为 91.7%和 76 .5 %。结论　在大肠杆菌中表达的Sta5 6重组抗原具有免疫反应性 ,纯化后可用作免疫诊断试剂。     

五日热巴通体重组外膜蛋白HbpA的研制和抗原性分析

为克隆并表达五日热巴通体外膜蛋白HbpA的基因,并对其抗原性进行初步分析,采用PCR方法从五日热巴通体基因组DNA扩增hbpA基因,将目的基因片段插入原核表达质粒pET32a（＋）,构建重组质粒pET32a（＋）-hbpA;将构建的重组质粒转化大肠杆菌BL21（DE3）并诱导目的基因表达,以SDS-PAGE电泳以及免疫印迹实验分析表达的目的蛋白。SDS-PAGE电泳分析发现pET32a（＋）-hbpA转化菌高效表达一48kDa重组蛋白;免疫印迹分析发现该蛋白与其免疫血清发生强烈反应;间接免疫荧光分析发现该重组蛋白免疫血清能特异识别五日热巴通体。实验结果表明五日热巴通体外膜蛋白HbpA的基因已在大肠杆菌中高效表达。     

恙虫病东方体Karp株47kD蛋白基因的表达及DNA免疫初步研究

目的　观察恙虫病东方体Karp株相对分子质量 (Mr)为 47× 10 3 蛋白基因的DNA免疫效果。方法　将恙虫病东方体Karp株Mr 为 47× 10 3 的蛋白基因插入真核表达载体pcDNA3.1( +) ,构建重组质粒pcDNA3.1 47。在证明该重组质粒可在哺乳动物COS7细胞中表达的基础上 ,单独和将其与Mr 为 40× 10 3 重组蛋白联合免疫小鼠。在每次加强免疫之后 10d ,检测小鼠体液和细胞免疫反应。结果　质粒DNA和蛋白联合免疫组所诱导的抗体水平和脾淋巴细胞增殖反应均高于重组质粒DNA和蛋白单独免疫组 ,而第二次加强免疫后重组质粒诱导脾淋巴细胞的增殖情况则显著弱于其它免疫组 (P <0 .0 5 )。结论　重组质粒pcDNA3 .1 47和重组Mr 为 47× 10 3 蛋白在刺激小鼠免疫反应上具有相互加强作用。     

合肥首例恙虫病病人血中东方体56kDa外膜蛋白部分基因的扩增及进化分析

采用恙虫病胶体金快速诊断试剂对安徽省合肥市一例不明原因发热病人血清进行检测,从该病人血块中提取DNA为模板,用恙虫病东方体特异性引物,PCR扩增出56 kDa外膜蛋白部分基因,将扩增目的片段克隆至T载体进行测序并进行基因进化分析.结果显示,该病人血清中抗恙虫病东方体总抗体、抗东方体IgG及抗东方体IgM阳性;患者给予强力霉素治疗后迅速退热.采用PCR从病人血标本中扩增出1 320 bp东方体56 kDa外膜蛋白基因片段,将基因片段测序结果在NCBI上做BLAST比对,显示该基因序列与昆明株和内蒙古株同源基因序列完全一致;进化树分析显示该序列与标准株Kuroki位于同一个分支.研究确认该发热病例为合肥市报告的首例恙虫病,其感染的恙虫病东方体为Kuroki型,推测合肥市可能为恙虫病新疫区.     

恙虫病东方体Sxh951株56kD蛋白的表达及其在ELISA中的应用

目的　构建含OrientiatsutsugamushiSxh95 1株 (Ot.Sxh95 1)相对分子质量 (Mr)为 5 6×10 3外膜蛋白基因 (sxh5 6 )的重组质粒pQE30 5 6 ,表达Mr5 6× 10 3蛋白并观察其在ELISA中的应用。方法　IPTG诱导sxh5 6重组质粒 ;观察SDS PAGE和免疫印迹结果 ;经Ni NTA亲和层析纯化后的重组蛋白分别与Ot.Gilliam、Ot.Karp、Ot.Kato感染鼠血清进行ELISA和免疫印迹检测。结果　SDS PAGE和免疫印迹检测显示有一Mr 约为 5 6× 10 3的特异蛋白带 ;ELISA和免疫印迹结果显示该重组蛋白只与Ot.Gilliam感染鼠血清呈阳性反应 ;重组蛋白用作ELISA包被抗原检测小鼠血清抗体IgG ,特异性为 10 0 % ,敏感性 96 .6 7% ;检测人血清抗体IgG的敏感性为 88.0 8% ,特异性 96 .36 %。结论　表达的重组Sxh5 6蛋白具有良好的免疫反应性 ;其作为ELISA包被抗原 ,具有良好的特异性和敏感性。     

HCV复合多表位抗原基因的克隆表达及其免疫学特性分析

目的构建丙型肝病炎病毒（HCV）截短C基因和多表位基因重组原核表达质粒,表达纯化融合蛋白,分析其免疫原性和抗原性。方法PCR方法扩增核心区羧基端部分缺失的基因片段Ct;合成HCVE2区模拟表位与NS3～NS57个表位基因Em;分别将Ct、Em克隆人原核表达质粒pQE30,筛选阳性重组质粒pQE30-CtEm,转化E．coli M15,IPTG诱导融合蛋白表达,薄层扫描分析表达蛋白;可溶性分析后用Ni^2＋-NTA凝胶亲和层析柱纯化、透析并浓缩融合蛋白;Westernblot分析纯化蛋白的特异性和抗原性;纯蛋白免疫小鼠后分析其免疫原性。结果成功构建了HCV复合多表位抗原基因的原核表达质粒pQE30-CtEm,目的基因可高效表达,表达产物主要以包涵体形式存在,Ni^2＋-NTA纯化可获得目的蛋白,纯化蛋白具有良好的抗原性和免疫原性。结论HCV复合多表位抗原基因融合蛋白可高效表达并得到纯化,该融合蛋白可作为HCV诊断抗原,也为丙型肝炎新型疫苗的研究提供了靶抗原。     

幽门螺杆菌napA-ctxB融合蛋白的基因克隆与表达

目的 克隆、表达幽门螺杆菌中性粒细胞激活蛋白napA与霍乱毒素B亚单位ctxB融合基因napA-ctxB(nctB),为制备预防H.pylori感染的疫苗奠定基础.方法 用PCR方法扩增ctxB目的基因片段,克隆至pQE30-napA质粒的napA基因上游,构建含双基因的表达质粒pQE30-napA-ctxB(pQE30-nctB),经测序分析确认后转化E.coli DH5α,经IPTG诱导表达融合蛋白NCTB,融合蛋白NCTB经镍离子柱纯化.结果 PCR扩增出807 bp的目的基因片段nctB.工程菌pQE30-nctB-DH5α经IPTG诱导后,SDS-PAGE显示有新生的蛋白表达条带,Mr为30 000,与预期的一致,约占菌体总蛋白的27%,重组蛋白用Ni2 -NTA 树脂提纯,纯化后的蛋白质经SDS-PAGE分析可见单一条带,图象软件分析表明纯度可达94%以上.Western blot 显示重组蛋白质有良好的抗原性.结论 构建含双基因的表达质粒pQE30-nctB成功,并在大肠杆菌DH5α中高效的表达.     

人CD7胞外区基因在大肠杆菌中的表达

目的 在大肠杆菌中表达人白细胞分化抗原CD7胞外区蛋白。方法 采用PCR技术调整CD7基因的阅读框架,使之与生物素化蛋白基因阅读框架一致,缺失了CD7cDNA基因的起始密码子并增加一个大肠杆菌偏性终止密码子,构建CD7胞外区cDNA和生物素化蛋白基因融合的原核表达质粒PinPointxa3-CD7。将重组质粒转入大肠杆菌DH5α表达,SDS-PAGE及Western blotting鉴定结果。结果 融合蛋白的分子量约为30000u,Western blotting结果表明,表达的蛋白质可被抗CD7的单克隆抗体识别。结论 为研制抗CD7基因工程抗体奠定了基础。     

伊氏锥虫微管结合蛋白p15基因的分子克隆与表达

根据报道的布氏锥虫(Trypanosoma brucei)微管结合蛋白p15(Tb-MAPp15)基因及其3′非翻译区保守序列设计引物,采用PCR法从伊氏锥虫云南水牛株(Trypanosoma evansi stock YNB)基因组DNA中克隆得到伊氏锥虫微管结合蛋白p15(Te-MAP p15)基因。克隆片段长273bp,编码90个氨基酸,预测分子量9.0kDa。经同源性比较,所得基因与Tb-MAP p15基因同源率达到94%。抗原性分析Te-MAP p15基因表达的氨基酸序列比T.brucei微管结合蛋白p15多5个,均参与组成其中1个抗原决定簇,并且此抗原决定簇序列形成在蛋白中常作为识别位点的α螺旋。将该基因亚克隆到pGEX-6P-1原核表达载体,转化大肠杆菌E.coli RS21宿主菌,经IPTG诱导,可成功表达。重组融合蛋白大小为35kDa,与预期大小一致,经SDS-PAGE和Western-blot鉴定为重组伊氏锥虫微管结合p15蛋白。     

Antigenic and genetic relatedness of eight Rickettsia tsutsugamushi antigens

The genetic and antigenic relatedness of eight antigens in three strains of Rickettsia tsutsugamushi has been studied by using recombinant organisms expressing epitopes of the 150-, 110-, 72-, 58-, 56-, 49-, 47-, and 20-kilodalton (kDa) polypeptide antigens of the Karp strain. Southern blot analysis of Karp, Kato, and Gilliam strain genomic DNA by using probes specific for each antigen class indicated that while strong homology exists between each of the corresponding antigen genes in these three strains, some restriction fragment length polymorphism exists. Antibodies affinity purified against each recombinant antigen class reacted with a comparably sized polypeptide in the Karp, Kato, and Gilliam strains in Western blots (immunoblots). Against more recent human isolates of R. tsutsugamushi, the affinity-purified antibodies against the 58-kDa recombinant antigen (anti-58-kDa) reacted with all nine isolates, anti-56-kDa reacted with eight of nine isolates, anti-47-kDa reacted with eight of nine isolates, anti-72-kDa reacted with eight of nine isolates, and anti-110-kDa reacted with four of nine isolates. Additional analysis indicated that the 110-kDa antigen may contain strain-specific epitopes similar to those previously reported for the 56-kDa polypeptide. Evidently, the strain heterogeneity among scrub typhus rickettsiae is a result of multiple components that exhibit variability in a background of strong homology.     

A recombinant surface protein of Babesia bovis elicits bovine antibodies that react with live merozoites

Ten monoclonal antibodies (MoAbs) were generated against five surface-exposed proteins (16 kDa, 42 kDa, 44 kDa, 60 kDa, 225 kDa) on merozoites of Babesia bovis. A genomic library constructed in the lambda gt11 expression vector was screened with MoAbs in a plaque immunoassay for identification of clones expressing recombinant surface proteins. Two recombinant clones were identified (lambda Bo44-15 and lambda Bo44-16) that encoded a protein recognized by a MoAb specific for an epitope on the native 44-kDa surface protein. Southern blot analysis using radiolabeled Bo44-15 DNA (1.25 kb) against merozoite DNA and bovine leukocyte DNA confirmed the parasite-specificity of the cloned insert and revealed multiple bands of hybridization with merozoite DNA. Western blot analyses of lambda Bo44-15 lysogen preparations demonstrated that recombinant protein production in this clone was IPTG-induced and that the recombinant molecule was a beta-galactosidase fusion protein. Additionally, recombinant 44-kDa protein, purified by immunoaffinity chromatography, reacted with specific MoAb in Western blot assay indicating that the integrity of the epitope was retained during purification. Immune sera from calves immunized with purified recombinant Bo44-15 protein immunoprecipitated metabolically radiolabeled merozoite protein of 44 kDa indicating that antibody induced by recombinant Bo44-15 protein recognized native 44-kDa protein. Also, these sera reacted with the surface of live merozoites as evidenced by indirect immunofluorescence assay. Serum antibody titers determined by this assay had a wide range.     

Expression and purification of the recombinant outermembrane protein Tp0453 of Treponema pallidum and its characterization of immuno-competence

ELISA test has been shown to have some advan tages in relation to the tests used for the diagnosisof syphilis because of its easy and quick perfor mance and result readings. With recent develop ment of the gene engineering technology and eluci dation of the whole genome of Nichols strain ofTreponema pallidum, new protein coding openreading frames (ORFs) are available for testing,and the study on the serological tests based on therecombinant protein have been become the focus ofinter…     

幽门螺杆菌UreB-Omp11融合蛋白的重组疫苗候选株构建和融合蛋白的表达、纯化及免疫学活性

目的：构建幽门螺杆菌（Hp）UreB-Ompll融合蛋白的重组疫苗候选株，在大肠杆菌中表达UreB-Ompll融合蛋白，并检测其免疫学活性。方法：用PCR方法扩增郑州分离坳菌株MEL-HP27的ureB和ompll基因并用重叠延伸PCR法获得ureB-ompl1融合基因，将融合基因ureB-ompl1插入原核表达载体pET30a（＋）、pET28a（＋）及pMAL-c2X中，筛选出合适的表达系统并进行融合蛋白的表达，采用Westernblot对表达产物进行鉴定，并用Amylose亲和层析法纯化融合蛋白，应用SDS-PAGE方法对纯化产物进行分析，纯化的融合蛋白辅以免疫佐剂皮下免疫小鼠，Westernblot对免疫小鼠血清进行检测。结果：特异PCR法、酶切鉴定并经测序分析后证实融合基因ureB—ompll克隆人表达载体pE330a（＋）、pET28a（＋）与pMAL—c2X中；重组菌TBl（pMAL-ureB—ompl1）经诱导获得了高效表达的MBP-UreB—Ompll融合蛋白，该融合蛋白可以被却免疫小鼠血清和却阳性患者血清中的相应抗体所识别，纯化后的融合蛋白纯度达90％以上。通过大肠杆菌抗原吸收法纯化免疫小鼠血清后，与纯化的融合蛋白进行杂交，结果显示在M，134000处出现特异杂交带，融合蛋白具有良好的免疫原性和免疫反应性。结论：成功地构建并筛选出了却MELHP27融合蛋白UreB-Ompl1的重组疫苗候选株TBl（pMAL-ureB—ompll），为坳蛋白质疫苗和核酸疫苗的研制奠定了基础。     

GST-snail融合蛋白的原核表达及其多克隆抗体制备

目的制备snail多克隆抗体,为深入研究其功能和探讨其与肿瘤等疾病的相关性提供工具。方法PCR扩增编码人snail 264个氨基酸的cDNA全长片段,DNA重组入原核表达质粒pGEX-4T-1,转化大肠杆菌BL21菌株,异丙基-β—D-硫代半糖苷（IPTG）诱导表达GST／Snail融合蛋白。经电泳纯化的融合蛋白免疫新西兰白兔,制备抗血清。通过ELISA、免疫荧光和免疫印迹法鉴定血清特异性和效价。结果成功构建了pGEX-4T-1／snail原核表达载体,转化BL21后可高效表达融合蛋白GST—snail,免疫产生的snail多抗可特异检测snail真核表达载体转染COS-7细胞后snail的表达及定位情况。结论获得了效价和特异性都良好的snail抗体,适合对snail的检测应用。     

人H5N1流感病毒M1基因的亚克隆及其在原核细胞的表达

目的 构建人H5N1亚型禽流感病毒A/Anhui/1/2005 M1蛋白的原核表达系统,为进一步研究M1蛋白的生物学功能和制备其诊断试剂奠定基础。方法 以该病毒基因节段七cDNA为模板,PCR扩增得到M1基因片段。将该片段亚克隆至载体pQE80-L中,构建重组质粒pQE80-L/M1,转化大肠埃希菌BL21（ DE3）。IPTG诱导重组蛋白表达。金属镍离子螯合层析纯化N末端携带多聚组氨酸标签的重组M1蛋白,免疫小鼠制备多克隆抗体。结果 获得了重组M1蛋白,能与抗H5N1亚型流感病毒血清发生特异性结合,且其免疫后能诱导机体产生特异性抗体。结论 成功获得了人H5N1亚型禽流感病毒M1蛋白在原核细胞中高效表达。     

Cloning of a Brucella melitensis group 3 antigen gene encoding Omp28, a protein recognized by the humoral immune response during human brucellosis.

Brucella group 3 antigens (Ags) are outer membrane proteins (OMPs) with a molecular mass ranging from 25 to 30 kDa. The OMPs are of interest partially because of their potential use as vaccine and diagnostic reagents. We used human convalescent antibody (Ab) to clone a gene that encoded a 28-kDa protein from a lambdagt11 library of Brucella melitensis 16M genomic DNA. DNA sequence analysis revealed a single open reading frame that would encode a protein of 26,552 Da. The 28-kDa protein had a primary amino acid sequence that was 43% similar to a previously described Brucella abortus group 3 Ag, Omp25 (P. de Wergifosse, P. Lintermans, J. N. Limet, and A. Cloeckaert, J. Bacteriol. 177:1911-1914, 1995). The similarity to a known group 3 OMP, immunoreactivity with Ab prepared against B. abortus group Ags, immunolabeling of whole cells, and Southern hybridization led to our conclusion that the B. melitensis 28-kDa protein was a group 3 protein distinct from B. abortus Omp25. We designated the B. melitensis protein Omp28. Human convalescent sera from patients infected with B. abortus and Brucella suis as well as rabbit antisera prepared against killed B. abortus whole cells recognized B. melitensis Omp28 on Western blots (immunoblots). Furthermore, mice and goats infected with smooth strains of B. melitensis produced Abs against Omp28. Our results may begin to explain the variability in molecular weight seen in Brucella group Ags and point toward their possible use in vaccination against infection as well as diagnosis of the disease.