甲型流感病毒NS1抗原捕获ELISA的建立

目的 建立基于单克隆抗体的甲型流感病毒非结构蛋白1(NS1)抗原检测的酶联免疫吸附(ELISA)法.方法 用甲型流感病毒NS1特异性单克隆抗体,通过抗体的优化组合,建立双抗体夹心抗原捕获ELISA,检测不同来源的流感病毒及副流感病毒.结果 对多种抗体组合进行反复筛选,最终确定了特异性检测到甲型流感病毒的NS1蛋白,而与乙型流感病毒和副流感病毒不发生交叉反应的最佳抗体组合.该方法 检测重组H5N1-NS1[A/HongKong/486/97(H5N1)-NS1和A/Vietnam/1194/04(H5N1)-NS1]蛋白的灵敏度最低检测值分别为15.6 ng/ml和240 pg/ml.结论 成功建立了甲型流感病毒NS1抗原捕获ELISA,为建立甲型流感病毒感染早期诊断新方法 奠定基础.     

甲型流感病毒NS1抗原捕获ELISA的建立

目的 建立基于单克隆抗体的甲型流感病毒非结构蛋白1(NS1)抗原检测的酶联免疫吸附(ELISA)法.方法 用甲型流感病毒NS1特异性单克隆抗体,通过抗体的优化组合,建立双抗体夹心抗原捕获ELISA,检测不同来源的流感病毒及副流感病毒.结果 对多种抗体组合进行反复筛选,最终确定了特异性检测到甲型流感病毒的NS1蛋白,而与乙型流感病毒和副流感病毒不发生交叉反应的最佳抗体组合.该方法 检测重组H5N1-NS1[A/HongKong/486/97(H5N1)-NS1和A/Vietnam/1194/04(H5N1)-NS1]蛋白的灵敏度最低检测值分别为15.6 ng/ml和240 pg/ml.结论 成功建立了甲型流感病毒NS1抗原捕获ELISA,为建立甲型流感病毒感染早期诊断新方法 奠定基础.     

禽流感病毒血凝素H5特异性单克隆抗体的制备及ELISA捕获法的建立

目的 制备和鉴定禽流感病毒(H5N1)血凝素(H5)特异性单克隆抗体(mAb),建立H5抗原的双抗体夹心ELISA捕获法.方法 以H5血凝素和携带H5全长基因的质粒免疫Balb/c小鼠制备mAb,利用血凝抑制(HI)实验筛选和鉴定,通过竞争抑制试验分析抗体识别表位,并采用抗体配对试验筛选捕获抗体和检测抗体,建立测定H5抗原的双抗体夹心ELISA捕获法.结果 获得16株特异性针对H5的单克隆抗体,与A型流感病毒H1、H3、H7、H9和B型流感病毒的血凝素无HI交叉反应,对H5血凝素的血凝抑制效价为1:100～1:51 200;通过配对实验,建立以单克隆抗体H5M9为捕获抗体,辣根过氧化物酶标记单克隆抗体H5M11为检测抗体的双抗体夹心ELISA;检测多株H5N1病毒和H5血凝素的最低检出值为1/32血凝单位,检测A型流感病毒H1N1、H3N2、B型流感病毒以及H7、H9血凝素均为阴性.结论 建立了一种灵敏度高、特异性强的测定H5抗原的ELISA捕获法,可应用于禽流感病毒H5N1感染的实验室早期诊断.     

禽流感病毒非结构蛋白1单克隆抗体的制备及其特异性分析

为研制禽流感病毒(H5N1)非结构蛋白1(NS1)的特异性单克隆抗体(mAb),并鉴定其特异性,本研究在分别表达了具有良好抗原性的A/Vietnam/1194/04(H5N1)-NS1和A/HongKong/486/97(H5N1)-NS1重组蛋白基础上,用A/Viet-nam/1194/04(H5N1)-NS1蛋白免疫BALB/c小鼠,取其脾细胞与小鼠骨髓瘤细胞进行融合,间接ELISA筛选阳性的杂交瘤细胞,并结合免疫荧光和免疫印迹对抗体的特异性进行鉴定,通过竞争抑制实验对单抗识别的抗原位点进行分析。结果共获得19株能识别4个H5N1-NS1蛋白不同抗原位点的mAb,亚类测定显示,5株为IgG2a、1株为IgG2b,另外13株为IgG1。这些mAb均与A/Vietnam/1194/04(H5N1)-NS1和A/HongKong/486/97(H5N1)-NS1重组蛋白特异性结合,免疫荧光检测均与A型流感病毒(H1N1和H3N2)有交叉反应,而与B型流感病毒无交叉现象。表明成功获得特异性针对H5N1-NS1蛋白的mAb,为进一步研究禽流感病毒NS1蛋白的结构与功能奠定基础。     

H5N1流感病毒M1蛋白免疫制备的单克隆抗体的研究

目的 制备抗人流感病毒H5N1株M1蛋白的单克隆抗体,为流感的快速诊断和研究提供新的工具.方法 应用在大肠埃希菌中表达的人H5N1亚型禽流感病毒(A/Anhui/1/2005)株M1蛋白,以纯化的表达产物免疫BALB/c小鼠,取脾细胞与sp2/0细胞系作细胞融合后,间接ELISA法筛选阳性的杂交瘤细胞,并应用间接免疫荧光法对抗体的特异性进行鉴定.结果 获得3株能稳定分泌抗禽流感病毒M1抗原的McAb杂交瘤细胞株,交叉反应试验及间接免疫荧光检测表明,三株McAb具有型特异性.结论 用H5N1禽流感病毒M1蛋白免疫制备的单克隆抗体,具有一定的交叉反应性,可用于多种亚型甲型流感病毒的检测.     

Ⅰ型登革病毒NS1抗原捕获ELISA的建立和初步临床诊断应用

目的以登革病毒特异性非结构蛋白1（NS1）单克隆抗体为基础建立Ⅰ型登革病毒（DEN1）抗原检测的酶联免疫吸附（ELISA）法，并探索从病人早期血清样品中检测DEN1-NS1的可行性。方法利用已制备的抗DEN1-NS1单克隆抗体（单抗），进行多种抗体组合配对优化模式的分析，建立双抗体夹心抗原捕获ELISA，以469份健康人血清样品确定cut off值，检测DEN1感染患者急性期血清样品。结果对多种抗体组合反复筛选，最终确立了最佳的包被单抗和酶标测定单抗，建立了抗体夹心捕获DEN1-NS1抗原的酶联免疫测定方法，能特异检测DEN1，与其他血清型登革病毒不发生交叉反应。检测16例临床确诊DEN1感染病人急性期血清样品，15例呈特异的抗原反应阳性。结论成功建立了DEN1-NS1抗原捕获ELISA并应用于临床血清样品的检测，为登革热的早期实验室诊断提供技术方法。     

抗原捕获ELISA检测卡波济肉瘤相关疱疹病毒的方法建立

目的 建立检测卡波济肉瘤相关疱疹病毒(KSHV)的抗原捕获ELISA方法,初步探讨其临床应用的可行性. 方法 以纯化的抗gpK8.1单克隆抗体(McAb)和多克隆抗体(PcAb)配对作为包被抗体和检测抗体,建立和优化抗原捕获ELISA检测方法,评价其敏感性、特异性和重复性,并初步用于3例已知KSHV阳性血清和257例临床血清样品中抗原的检测. 结果 包被的McAb浓度为5μg/ml、检测抗体浓度为1.6 μg/ml时,P/N值最高,检测的敏感度为31.28 ng/ml,且与EB病毒(ESV)、单纯疱疹病毒1型(HSV-1)、单纯疱疹病毒2型(HSV-2)等抗原无交叉反应,特异性高.检测3例KSHV阳性患者血清均为阳性,在257例临床血清样品中,4例捕获到KSHV抗原. 结论 建立了检测KSHV的抗原捕获ELISA方法,为可能的KSHV检测试剂研制提供重要实验依据.     

人高致病性H5N1亚型禽流感病毒NS1蛋白多克隆抗体的制备及鉴定

目的 制备高灵敏度和高特异性的人高致病性H5N1亚型禽流感病毒NS1蛋白抗体并对其效价进行初步评估.方法 构建含有H5N1亚型禽流感病毒NS1序列的pET-28a(+)重组载体的大肠埃希菌BL21(DE3),诱导表达NS1蛋白,并经Ni-NTA色谱柱亲和层析纯化获得NS1重组蛋白,并进行SDS-PAGE和Western Blot鉴定.以纯化的蛋白为抗原免疫新西兰大白兔,获得兔抗NS1血清,亲和纯化获得多克隆抗体.应用ELISA和Western Blot检测纯化抗体的效价和特异性.结果 NS1融合蛋白得到高表达,且纯度＞90％,用该融合蛋白免疫新西兰大白兔后得到的抗NS1多克隆抗体,效价达1∶80 000,并特异性识别H5N1亚型禽流感病毒NS1蛋白.结论 获得了NS1多克隆抗体,具有较好的效价和特异性.     

多重RT-PCR方法检测甲型流感病毒

目的建立一种快速、敏感、特异的多重RT-PCR,同时检测甲型流感病毒中的3个分型:甲型H1N1流感病毒,季节性H1N1流感病毒,季节性H3N2流感病毒,并将此方法应用到实验室流感病毒核酸检测技术中。方法利用甲型流感病毒3个分型病毒的引物,在同一个RT-PCR反应体系中,对疑似流感咽拭子标本进行检测。结果多重RT-PCR对甲型流感病毒中分型病毒有较高的灵敏度和特异性,可直接从疑似流感标本中同时进行甲型流感病毒分型检测。结论此实验中采用的多重RT-PCR具有与常规RT-PCR一样的特异性和敏感度,而且比普通RT-PCR和病毒分离法更快速,也更简便。     

登革病毒非结构蛋白NS1群特异性单克隆抗体的制备及初步应用

目的制备登革病毒NS1群特异性单克隆抗体,建立可检测登革病毒1～4型NS1抗原的ELISA检测法,为登革热的早期快速诊断奠定基础。方法应用毕赤酵母表达系统分泌表达登革病毒2型重组非结构蛋白NS1,以此为抗原免疫BABL/c小鼠,取其脾细胞与小鼠骨髓瘤细胞融合,经HAT选择培养、间接ELISA筛选和亚克隆,获得能稳定分泌登革病毒NS1群特异性单克隆抗体的杂交瘤细胞株;用所获得的单克隆抗体建立可检测1～4型登革病毒NS1抗原的双抗体夹心ELISA法。结果从登革病毒2型NS1重组毕赤酵母（Pichia Pastoris-NS1）中获得了大量纯化的登革病毒重组NS1蛋白;经免疫小鼠、细胞融合、间接ELISA筛选及3次亚克隆后,最终获得2株能高效分泌抗登革病毒NS1单克隆抗体的杂交瘤细胞株2D7B6B4和2D10E2F6,间接ELISA显示抗体效价高达1∶8000～1∶16000;ELISA及免疫荧光检测证实,其所分泌的抗体与1～4型登革病毒及其重组NS1蛋白均有特异性免疫反应,为登革病毒NS1群特异性单克隆抗体;两株单克隆抗体均为IgG2a亚类;初步建立了检测4个血清型登革病毒NS1抗原的双抗体夹心ELISA法。结论成功研制出两株能高效分泌抗登革病毒NS1群特异性单克隆抗体的杂交瘤细胞株。初步建立了可检测1～4型登革病毒NS1抗原的双抗体夹心ELISA检测法。     

Diagnostic approach for differentiating infected from vaccinated poultry on the basis of antibodies to NS1, the nonstructural protein of influenza A virus

Vaccination programs for the control of avian influenza (AI) in poultry have limitations due to the problem of differentiating between vaccinated and virus-infected birds. We have used NS1, the conserved nonstructural protein of influenza A virus, as a differential diagnostic marker for influenza virus infection. Experimentally infected poultry were evaluated for the ability to induce antibodies reactive to NS1 recombinant protein produced in Escherichia coli or to chemically synthesized NS1 peptides. Immune sera were obtained from chickens and turkeys inoculated with live AI virus, inactivated purified vaccines, or inactivated commercial vaccines. Seroconversion to positivity for antibodies to the NS1 protein was achieved in birds experimentally infected with multiple subtypes of influenza A virus, as determined by enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. In contrast, animals inoculated with inactivated gradient-purified vaccines had no seroconversion to positivity for antibodies to the NS1 protein, and animals vaccinated with commercial vaccines had low, but detectable, levels of NS1 antibodies. The use of a second ELISA with diluted sera identified a diagnostic test that results in seropositivity for antibodies to the NS1 protein only in infected birds. For the field application phase of this study, serum samples were collected from vaccinated and infected poultry, diluted, and screened for anti-NS1 antibodies. Field sera from poultry that received commercial AI vaccines were found to possess antibodies against AI virus, as measured by the standard agar gel precipitin (AGP) test, but they were negative by the NS1 ELISA. Conversely, diluted field sera from AI-infected poultry were positive for both AGP and NS1 antibodies. These results demonstrate the potential benefit of a simple, specific ELISA for anti-NS1 antibodies that may have diagnostic value for the poultry industries.     

Influenza A viral nucleoprotein detection in isolates from human and various animal species

Summary A double antibody sandwich, enzyme-linked immunosorbent assay (DAS-ELISA) was developed to detect influenza A viral antigen, employing a monoclonal antibody directed against type-specific influenza A nucleoprotein (McAb anti-NP). McAb anti-NP was used to coat ELISA plates as well as to prepare the peroxidase conjugate. Influenza A viruses of avian, equine, swine, and human origin were detected in allantoic fluids of inoculated eggs with higher sensitivity by the DAS-ELISA than by hemagglutination (HA) assays. Minimal concentrations of 8 ng/ml influenza virus protein were detected in Nonidet P40-treated virus preparations. Viral antigen detection in tissues of experimentally infected chickens and pigs was successful, but in pigs yielded a lower positive score than the conventional method of virus isolation in eggs. The test is sensitive, rapid, and easy to perform, but does not permit influenza A subtyping. In avian species, the McAb anti-NP DAS-ELISA differentiates between influenza and Newcastle disease viruses. In pigs, the test distinguishes between influenza and Aujeszky's disease.     

三种ELISA法检测HFRSV抗原的比较

本文报告了BA-ELISA、夹心法ELISA和抗体捕获法ELISA对五株肾综合征出血热病毒(HFRSV)细胞培养物和感染乳鼠脑中病毒抗原的检测情况,结果表明BA-EL ISA敏感性最高,对HFRSV细胞培养物的检测滴度平均达1:576～2304,对感染乳鼠脑研磨液上清平均达1:2000～11200。由于三种方法均采用了HFRS单克隆抗体,因此非特异反应显著降低,敏感性得以提高。文中对三种ELISA方法的优缺点进行了讨论。     

Defining the levels of secreted non-structural protein NS1 after West Nile virus infection in cell culture and mice

Infection with West Nile virus (WNV) causes a febrile illness that can progress to meningitis or encephalitis, primarily in humans that are immunocompromised or elderly. For successful treatment of WNV infection, accurate and timely diagnosis is essential. Previous studies have suggested that the flavivirus non-structural protein NS1, a highly conserved and secreted glycoprotein, is a candidate protein for rapid diagnosis. Herein, we developed a capture enzyme-linked immunosorbent assay (ELISA) to detect WNV NS1 using two anti-NS1 monoclonal antibodies (mAbs) that map to distinct sites on the protein. The capture ELISA efficiently detected as little as 0.5 ng/ml of soluble NS1 and exhibited no cross-reactivity for yellow fever, Dengue, and St. Louis encephalitis virus NS1. The capture ELISA reliably detected NS1 in plasma at day 3 after WNV infection, prior to the development of clinical signs of disease. As the time course of infection continued, the levels of detectable NS1 diminished, presumably because of interference by newly generated anti-NS1 antibodies. Indeed, treatment of plasma with a solution that dissociated NS1 immune complexes extended the window of detection. Overall, the NS1-based capture ELISA is a sensitive readout of infection and could be an important tool for diagnosis or screening small molecule inhibitors of WNV infection.     

Monoclonal antibody-based antigen capture immunoassay for detection of circulating non-structural protein NS1: implications for early diagnosis of Japanese encephalitis virus infection

An early diagnosis of Japanese encephalitis (JE) is important for timely clinical management and epidemiological control in areas where multiple flaviviruses are endemic. The NS1 antigen has an advantage over IgM enzyme-linked immunosorbent assay (ELISA) for early confirmatory diagnosis of Japanese encephalitis virus (JEV) infection due to its proliferation on the surface of the host cells in the acute phase of infection. In this study, the development and evaluation of JE-specific NS1 antigen capture ELISA is described using high-affinity monoclonal antibody specific to the recombinant NS1 protein for early diagnosis of JE. The gene encoding NS1 protein was cloned and expressed in the pQE30UA expression vector followed by purification of the recombinant protein by affinity chromatography. A sandwich ELISA for antigen detection was developed using purified rabbit IgG antibody and mouse monoclonal antibody as the capture and detector antibody, respectively. The application of JE NS1 antigen ELISA for early diagnosis was evaluated with 120 acute phase sera and 80 CSF samples. The comparative evaluation of the JE NS1 antigen ELISA by real-time RT-PCR revealed 97% concordance with a sensitivity and specificity of 97% and 98%, respectively. The JE NS1 antigen was detectable in the blood from the first day up to day 9 after the onset of symptoms. These findings suggest that the JEV NS1 antigen capture ELISA may help early diagnosis of JE infection.     

Infectious influenza A and B virus variants with long carboxyl terminal deletions in the NS1 polypeptides

An influenza A virus, A/turkey/Oregon/71, was shown by protein gel analysis to code for an NS1 protein approximately half the size of those of other influenza A viruses. Sequence analysis of the NS gene of this virus revealed a 10 nucleotide deletion resulting in an NS1 protein of only 124 amino acids. This truncated NS1 polypeptide retained its karyophilic pattern as detected by indirect immunofluorescence analysis of virus infected cells. Also, A/turkey/Oregon/71 virus grew to high titer in embryonated chicken eggs comparable to other influenza A viruses. We also identified a laboratory variant of an influenza B virus, clone 201, which codes for a truncated NS1 protein. Sequence analysis revealed a 13 nucleotide deletion resulting in a shortened NS1 protein of only 127 amino acids as compared to other influenza B virus NS1 proteins possessing a length of 281 amino acids. Again as shown for the NS1 proteins of other influenza B viruses the NS1 polypeptide of B virus clone 201 was found to localize in the nucleus of infected cells. It appears that large deletions in the carboxyl terminus of the NS1 proteins of influenza A and B viruses can be tolerated without affecting the functional integrity of the NS1 polypeptide.