西尼罗河病毒NS1的克隆、表达及抗原性分析

目的克隆和表达西尼罗河病毒（WNV）非结构蛋白1（NS1）,并分析其与登革病毒NS1的抗原交叉反应性。方法合成WNV NS1全基因序列,将NS1全基因克隆到pGEX-5X-3原核表达载体中表达GST—NS1融合蛋白,用4型登革病毒免疫血清及登革病毒NS1单克隆抗体并应用Western Blot方法分析WNV—NS1重组蛋白的抗原性。结果重组质粒pGEX-5X-3-WNV—NS1经IPTG诱导,高效表达GST-NS1融合蛋白,经变性纯化和复性获得可溶性WNV-NS1重组蛋白,经WesternBlot证实WNV—NS1重组蛋白可与各型登革病毒免疫小鼠血清及部分4型登革病毒NS1交叉单抗识别。结论成功获得可溶性WNV—NS1重组蛋白,该蛋白与登革病毒NS1具有抗原交叉反应性,其结果为建立西尼罗河病毒的血清学诊断和鉴别诊断奠定了基础。     

Ⅱ型登革病毒NS1基因的克隆及其在昆虫细胞中的表达

目的获得II型登革热病毒NS1基因并在昆虫细胞中表达,为进一步研发登革热血清学检测试剂盒提供抗原。方法RT-PCR扩增II型登革热病毒NS1基因并测序列,并定向克隆入杆状病毒转移载体pFastBac-HTA,获得重组转移载体pFastBac-NS1。并将pFastBac-NS1转化到DH10Bac感受态细胞中,筛选到重组转座子rBacmid-NS1。在脂质体介导下将rBacmid-NS1转染Sf9昆虫细胞获得重组杆状病毒rBV-NS1。rBV-NS1感染Sf9细胞后,通过SDS-PAG和Western blot检测NS1重组蛋白。结果成功克隆II型登革病毒NS1基因,SDS-PAGE、间接免疫荧光和Western blot检测表明NS1基因在昆虫细胞得到表达,能与登革患者血清发生特异性免疫反应,具有免疫原性。结论II型登革病毒非结构蛋白NS1在昆虫中表达,为进一步研究NS1的生物学特性和血清学检测奠定基础。     

II型登革病毒NS1基因的克隆及其在昆虫细胞中的表达

目的获得II型登革热病毒NS1基因并在昆虫细胞中表达,为进一步研发登革热血清学检测试剂盒提供抗原。方法RT-PCR扩增II型登革热病毒NS1基因并测序列,并定向克隆入杆状病毒转移载体pFastBac-HTA,获得重组转移载体pFastBac-NS1。并将pFastBac-NS1转化到DH10Bac感受态细胞中,筛选到重组转座子rBacmid-NS1。在脂质体介导下将rBacmid-NS1转染Sf9昆虫细胞获得重组杆状病毒rBV-NS1。rBV-NS1感染Sf9细胞后,通过SDS-PAG和Western blot检测NS1重组蛋白。结果成功克隆II型登革病毒NS1基因,SDS-PAGE、间接免疫荧光和Western blot检测表明NS1基因在昆虫细胞得到表达,能与登革患者血清发生特异性免疫反应,具有免疫原性。结论II型登革病毒非结构蛋白NS1在昆虫中表达,为进一步研究NS1的生物学特性和血清学检测奠定基础。     

登革热病毒Ⅰ型外膜蛋白DⅢ区的克隆、表达及重组蛋白的应用

目的选取DVⅠ外膜蛋白DⅢ区基因进行克隆、表达和纯化,以获得能应用于血清学诊断的纯化重组蛋白。方法用RT-PCR和套式PCR法扩增登革病毒Hawaii株外膜蛋白DⅢ区基因,与表达载体pET-30a连接,构建重组表达载体,在大肠杆菌BL21(DE3)中表达,重组蛋白经Western-blot鉴定活性后用电洗脱法进行纯化。纯化的重组蛋白用间接ELISA法和捕获ELISA法应用于血清学检测,检测结果与间接免疫荧法进行比较。结果重组表达质粒在大肠杆菌中表达高产量的重组蛋白,Western-blot结果显示重组蛋白具有免疫活性。纯化的重组蛋白对登革热病毒Ⅰ型感染者具有很高的检出率,与间接免疫荧光法检测结果基本相符。结论DVⅠ外膜蛋白DⅢ区基因在大肠杆菌中成功表达,重组蛋白可应用于血清学检测。     

黄热病毒NS1蛋白的制备及免疫原性鉴定

目的 原核系统克隆表达黄热病毒(yellow fever virus, YFV)非结构蛋白1(nonstructural protein 1,NS1),鉴定其免疫原性。方法 以YFV-17D疫苗株为模板,常规分子生物学方法构建pQE30-YFV NS1表达载体,原核表达纯化YFVNS1重组蛋白;免疫印记、免疫荧光和酶联免疫吸附实验验证其免疫原性。结果 成功构建重组质粒pQE30-YFV NS1,制备纯化可溶性YFV NS1蛋白;该重组YFV NS1蛋白与登革病毒、黄热病毒、乙脑病毒、西尼罗河病毒免疫小鼠腹水及寨卡病毒NS1、YFV NS1蛋白免疫小鼠血清均发生反应,重组YFV NS1蛋白免疫小鼠血清与YFV感染细胞超声上清也发生反应。结论 获得高纯度YFV NS1重组蛋白,且具有较好的免疫原性,含天然NS1蛋白表位,为基于NS1黄热病毒早期抗原诊断方法和蛋白功能研究奠定基础。     

多房棘球蚴LDH基因的克隆表达及免疫原性研究

目的克隆表达青海省多房棘球蚴(Echinococcus multilocularis,Em)乳酸脱氢酶(lactate dehydrogenase,LDH)基因,鉴定EmLDH重组蛋白的免疫原性,初步评价其免疫诊断价值。方法采用RT-PCR方法克隆EmLDH基因,将其连接入pET15b表达载体中,构建重组表达质粒pET15b-EmLDH,转化至E.coli Rosetta(DE3)感受态细胞进行诱导表达。通过SDS-PAGE检测重组蛋白的表达形式,Ni-IDA树脂亲和层析纯化重组蛋白。通过Western blotting法鉴定EmLDH重组蛋白的免疫原性,ELISA法检测泡型包虫病患者(57例)、囊型包虫病患者(33例)和正常人(50例)血清,初步评价EmLDH重组蛋白的免疫诊断效果。结果成功克隆了EmLDH基因并表达纯化出相应的重组蛋白。Western blotting结果显示,EmLDH重组蛋白可被泡型和囊型包虫病患者血清识别,而不被正常人血清识别。ELISA结果显示,EmLDH重组蛋白对泡型和囊型包虫病患者血清的诊断敏感性分别为84.21%和84.85%。结论 EmLDH重组蛋白具有较高的免疫原性,对包虫病具有较好的免疫诊断价值。     

4种血清型登革病毒多表位重组抗原的表达及血清学初步评价

目的在原核表达系统中对登革病毒包膜蛋白(E蛋白)和非结构蛋白1(NS1)融合的B细胞抗原表位进行表达、纯化及血清学评价。方法将B细胞抗原表位用形成α螺旋的连接肽(EAAAK)2作为接头,串联合成1条全新的多表位融合重组基因rE,将其克隆到原核表达载体pET-28a(+)中,转化大肠杆菌BL21(DE3)后经IPTG诱导表达融合蛋白,用镍柱对重组蛋白纯化,并用SDS-PAGE和Western blot方法鉴定表达产物。以融合蛋白为抗原,用间接ELISA检测登革热病人血清IgM抗体。结果重组表达载体pET28a-rE构建成功,并在大肠杆菌BL21(DE3)中成功表达。融合蛋白主要以包涵体形式存在,用镍柱纯化获得高纯度的目的蛋白,SDS-PAGE和Western blot检测结果显示蛋白分子量大小与预期结果相符,建立的间接ELISA具有较高的准确性。结论原核表达的登革病毒多表位融合蛋白具有良好的血清学检测价值。     

刚地弓形虫peroxiredoxin基因的克隆表达与免疫原性分析

目的对刚地弓形虫peroxiredoxin(TgPrx)基因进行克隆、表达和免疫原性分析。方法收集、纯化RH株弓形虫速殖子,提取总RNA;设计合成引物并引入EcoRI和XhoI酶切位点,RT-PCR扩增编码TgPrx的基因片段克隆到原核质粒pET30a(+)中,经双酶切、PCR及测序鉴定阳性克隆;在大肠杆菌BL21/DE3中用IPTG诱导表达,表达产物经SDS-PAGE进行鉴定,重组蛋白用Western blotting分析其免疫原性。结果从弓形虫RH株cDNA中扩增出591bp的TgPrx基因片段,并成功构建重组质粒pET30a(+)/TgPrx;SDS-PAGE结果表明,目的基因在大肠杆菌BL21/DE3中高效表达。重组蛋白的相对分子量约32kDa,Western blotting显示其能被兔抗弓形虫免疫血清识别。结论RH株刚地弓形虫peroxiredoxin可在原核表达系统中高效表达,该重组蛋白具有免疫原性,有望作为弓形虫疫苗的候选抗原。     

肺炎支原体热休克蛋白HSP70的表达、纯化及其免疫原性分析北大核心CSCD

目的构建肺炎支原体(MP)热休克蛋白HSP70重组原核表达质粒,纯化并鉴定其免疫原性。方法以肺炎支原体ATCC 29342为模板,利用搭桥PCR扩增HSP70全序列,胶回收纯化后测序验证。使用BamH1和Xho1双酶切PCR产物,构建重组表达质粒pGEX-4T-1-HSP70,转入大肠埃希菌BL21中,经IPTG诱导目的蛋白表达,对表达产物进行12.5%SDS-PAGE和质谱鉴定。利用AKTA explore 100蛋白纯化仪纯化重组HSP70,以此为抗原与MP感染者血清进行Western blot,检测其免疫反应性。结果搭桥PCR成功完成HSP70基因A1728G突变,重组质粒pGEX-4T-1-HSP70构建正确,转化BL21后经IPTG诱导表达分子质量单位92 ku含GST标签的重组HSP70,纯化蛋白经Western blot检测能与感染Ⅰ型和Ⅱ型MP菌株患儿血清发生特异性反应。结论获得重组HSP70完整蛋白,纯化产物具有免疫反应性,为制备高效防治肺炎支原体感染的基因工程疫苗及研究HSP70蛋白的免疫学功能奠定了基础。     

华支睾吸虫PPMP型抗原基因的克隆、表达与免疫原性鉴定

目的筛选华支睾吸虫成虫cDNA表达文库,寻找和鉴别新颖的抗原基因,并分析其重组蛋白的免疫原性方法以华支睾吸虫病患者混合血清免疫筛选华支睾吸虫成虫λZAP cDNA表达文库,将阳性噬菌体克隆、测序,对获得的核苷酸序列进行生物信息学分析。将目的基因成熟肽的编码区克隆至原核表达质粒pET28b(+),转化至大肠埃希菌BLR(DE3),异丙基-β-D硫代半乳糖苷(IPTG)诱导表达。用组氨酸标签亲和纯化柱(Ni-NTA树脂)纯化表达产物,蛋白质印迹(Western blotting)分析其免疫原性。以纯化的重组蛋白pET28b-Cs2免疫BALB/c小鼠,制备免疫血清,ELISA检测抗体水平。结果共获得44个阳性克隆,其中3个克隆的氨基酸序列中均含有PPMP重复序列,将其命名为华支睾吸虫PPMP型抗原,将其中含有KPPMPGDRDA、QPPMPGGRDA串联重复多肽序列的抗原分别称为PPMPⅠ型和PPMPⅡ型抗原。经核苷酸序列同源性比较,PPMP型抗原是一个新的华支睾吸虫特异性抗原家族。PPMPⅠ型的Cs2基因和PPMPⅡ型的Cs3基因的成熟肽编码区在大肠埃希菌BLR(DE3)或BLR(DE3)pLysS中表达,并获得可溶性重组蛋白,2个重组蛋白的相对分子质量分别为M_r 22 000和M_r 39 000。重组蛋白可被华支睾吸虫病患者血清所识别。ELISA结果显示,免疫小鼠可产生高滴度(1:64000)特异性IgG抗体。结论发现华支睾吸虫PPMP型抗原基因家族,其重组蛋白具有较强的免疫原性。     

Ⅱ型登革病毒非结构蛋白NS1血清型特异性单克隆抗体的制备与鉴定

目的制备并鉴定Ⅱ型登革病毒非结构蛋白NS1(DV2-NS1)的血清型特异性单克隆抗体。方法以具有良好抗原性的重组DV2-NS1蛋白与灭活的Ⅱ型登革病毒(DV2)混合免疫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、IFA法筛选,ELISA、IFA及WesternBlot对mAbs的类型及亚类、交叉实验及特异性等进行鉴定。结果免疫的Balb/c小鼠经多次融合筛选,共获得14株血清型特异性抗DV2-NS1蛋白的mAbs,其亚类测定两株为IgG2b,余均为IgG1。ELISA和免疫印迹显示这些mAbs与重组DV2-NS1蛋白和DV2抗原均特异性结合,IFA结果显示这14株单抗特异结合Ⅱ型登革病毒,与其它3型登革病毒无交叉。结论成功获得了特异性针对DV2-NS1蛋白的mAb,为进一步研究NS1蛋白的结构和功能以及研制早期诊断试剂奠定基础。     

Recognition of a multiple antigen peptide containing sequence from mimotope of the dengue type 3 virus NS4B protein by human antibodies

Objective: To evaluate the recognition of NS4 B mimotope, as multiple antigen peptide(MAP), by dengue antibodies presents in serum samples from patients with different serotype infections. Methods: A MAP containing mimotope sequence was synthesized and used to evaluate the recognition of NS4 B mimotope as MAP by a panel of 66 human sera from dengue cases by an indirect ELISA assay. Results: The MAP differentiated between sera from dengue viruses infected patients and sera from healthy individuals and the best reactivity was shown by serum from dengue type 3 virus patients. The recognition was more intense with serum from patients with secondary infection. Conclusions: The findings suggest the potential use of NS4 B mimotope on the development of a multi-epitope diagnostic tool. These results are important for further immunogenicity studies.     

Analysis of antibody response in human dengue patients from the Mexican coast using recombinant antigens

This study was undertaken to evaluate the feasibility of using recombinant dengue proteins to discriminate between acute dengue infections versus uninfected dengue samples. Dengue virus proteins E, NS1, NS3, and NS4B were cloned as fusion proteins and expressed in Escherichia coli. Recombinant products were tested in 100 serum samples obtained from acute dengue fever cases collected from 3 states of Mexico where dengue is endemic. Sera from 75 healthy individuals living in nonendemic areas for dengue were used as a control group. In sera from the dengue patients group, antibody responses to E protein were demonstrated in 91% of cases and NS1 protein was recognized to various extents (99%) within the first 7 days of infection. The antibody responses to NS3 and NS4B were frequently of low magnitude. Consistent negative antibody responses to all proteins were found in sera from the control group. These data suggest that the glutathione-S-transferase (GST)-dengue fusion proteins may be feasible antigens for a sensitive and specific serological assay.     

我国登革2型病毒分离株E蛋白B抗原区的表达与鉴定

目的登革2型病毒(DEN2)E蛋白B抗原区的融合表达、纯化和抗原性初步分析。方法将DEN2GZ14株E蛋白B抗原区基因连接到克隆载体pGEM-T并转染E.coliDH5α,酶切后连接至表达载体pET-32a(+)并转染E.coliBL21,IPGT诱导表达,WesternBlot和间接ELISA分析表达产物的抗原性。结果含有DEN2E蛋白B抗原区基因质粒的表达菌表达了相对分子量为31kDa的融合蛋白,WesternBlot分析表明其能与小鼠多克隆抗体发生特异性反应,间接ELISA分析其与10例登革2型病毒感染者血清发生阳性反应。结论获得的DEN2GZ14株E蛋白B抗原区的基因表达蛋白有良好的抗原性。     

Induction of bivalent immune responses by expression of dengue virus type 1 and type 2 antigens from a single complex adenoviral vector

There are approximately 100 million new cases of dengue (DEN) virus infection each year. Infection can result in illness ranging from a mild fever to hemorrhaging, shock, or even death. There are four serotypes of dengue virus (DEN1-4), and immunity to one serotype does not cross protect from infection with other serotypes. Currently there are no approved vaccines for dengue fever. In this report, we describe the construction of a bivalent dengue virus vaccine using a complex recombinant adenovirus approach to express multiple genes of DEN1 and DEN2 serotypes. In vaccinated mice, this vector induced humoral immune responses against all four dengue serotypes as measured by enzyme-linked immunosorbent assay. However, the neutralizing antibody responses were specific for DEN1 and DEN2 serotypes. Expansion of this vaccine development platform towards the DEN3 and DEN4 serotypes can lead towards the development of an adenovirus-based tetravalent dengue vaccine.     

Use of dengue NS1 antigen for early diagnosis of dengue virus infection

Accurate and timely diagnosis of dengue virus is important for early detection of dengue virus infection. In this study, the usefulness of the dengue NS1 antigen test was evaluated as a routine, rapid diagnostic test for dengue virus infection. A total of 208 sera from patients suspected of having dengue virus infection were collected and tested for dengue antibody, dengue genome and dengue NS1 antigen. Dengue antibody test, dengue PCR test and dengue antigen test were able to detect dengue virus infection from Days 1 to 8 in 72.8, 52.8 and 44.0% of samples, respectively. Of the 208 sera tested, 69.2% (144/208) of the acute sera were positive for dengue virus infection based on IgM antibody, IgG antibody, NS1 antigen and PCR tests. Thirty-two point two percent of the samples (67/208) were found positive for dengue NS1 antigen, 38.5% (80/208) were PCR positive, 40.9% (85/208) were IgM positive and 36.1% (75/208) were IgG positive for dengue virus. The results reveal the detection rate of dengue virus infection was similar for PCR and dengue antibody (65.9%) and for NS1 antigen and dengue antibody (62.0%) combinations. Therefore, the dengue NS1 antigen test can be used to complement the current antibody test used in peripheral laboratories. Thus, the combination of the NS1 antigen and antibody tests could increase the diagnostic efficiency for early diagnosis of dengue infection.     

登革热病毒外膜蛋白基因的克隆、表达

目的　在大肠杆菌中表达登革热病毒外膜抗原基因 ,获得能作为检测抗原的重组蛋白。方法　登革热 2型病毒NGC株感染C6/ 36细胞后 ,抽提病毒RNA ,经逆转录和套式PCR扩增出E基因片断 ,扩增片段经酶切、连接、克隆 ,构建重组表达质粒。并转化大肠杆菌DH5α。结果　重组质粒经诱导后表达外膜抗原的部分肽链。经过免疫印迹证实其具有免疫反应性。结论　截断的部分E蛋白基因在大肠杆菌中表达成功 ,重组的蛋白可作为血清学检测抗原使用