间接法和夹心法HCV抗体诊断试剂盒的诊断性能评价与选择

目的对国产双抗原夹心酶联免疫法和间接酶联免疫法丙型肝炎抗原检测试剂进行诊断性能评价与选择。方法选择1种夹心法和3种间接法国产检测试剂,同时对60份血清盘标本和40份血液筛查标本进行检测,血液筛查标本的检测结果为阳性或灰区,并经确认试验确认。试剂间比较采用配对卡方检验;对假阴性率进行R×C列联表检验。结果 3种间接法试剂和夹心法试剂的灵敏度分别为90.2%、78.0%、95.1%和97.6%;特异度分别为78.1%、72.6%、94.1%和100%。夹心法的分析灵敏度比间接法高4~8倍,不同试剂及试剂组合的R×C列联表检验结果:χ2=29.898,P0.05。结论夹心法试剂诊断特性优于间接法试剂,夹心法与间接法试剂搭配,可明显降低假阴性率,有效防止漏检。     

Double-antibody sandwich ELISA using biotinylated antibodies for the detection of Echinococcus granulosus coproantigens in dogs

Here we present the diagnostic evaluation of an improved double-antibody sandwich ELISA for detecting Echinococcus granulosus antigens in dog faecal samples (coproantigens). A purified rabbit IgG fraction against protoscolex excretory-secretory products was used as primary antibody, and the same fraction conjugated with biotin as secondary antibody. In order to validate the sandwich ELISA, intra- and inter-assay precision, linearity, and recovery percentages were calculated. The diagnostic evaluation of the method was carried out by investigating faecal samples from 37 dogs naturally infected with E. granulosus, 15 Echinococcus-free dogs infected with Taenia spp., 82 dogs with non-taeniid helminths and 66 dogs free of helminth infections. An overall sensitivity of 78.4% and specificity of 93.3% were determined. Positive and negative predictive values were 72 and 95%, respectively, and the diagnostic efficiency was 90.5%. In addition, the sandwich ELISA detection limit was estimated in 5.12 ng ml(-1). These results are highly satisfactory, allowing the use of this methodology in surveillance and control programs for intestinal echinococcosis in dogs.     

双抗体夹心ELISA法检测广州管圆线虫循环抗原的研究

目的建立双抗体夹心ELISA法检测广州管圆线虫循环抗原(Cag)。方法采用两株抗广州管圆线虫成虫可溶性抗原单克隆抗体,应用双抗体夹心ELISA法检测广州管圆线虫CAg,并摸索该法的最佳实验条件。对感染大鼠、小鼠、疑似和确诊广州管圆线虫病病例血清进行检测,评价方法的敏感性;对日本血吸虫、肺吸虫、旋毛虫、囊虫病人血清进行交叉反应试验,评价方法的特异性。结果10μg/ml单抗包被,酶标记单抗1∶1 600稀释为最佳工作浓度。利用该法检测不同血清广州管圆线虫循环抗原的敏感性为84.2%~87.2%,特异性为100%。结论建立的双抗体夹心ELISA法检测广州管圆线虫循环抗原具有敏感性高、特异性强和经济、简便易行等优点。     

犬恶丝虫病ELISA诊断方法的建立

目的建立犬恶丝虫病的ELISA诊断方法。方法将犬恶丝虫成虫粗制抗原经过SephaexG-200凝胶柱层析后进行间接ELISA试验，确定最佳实验条件，建立犬恶丝虫病的同种纯化抗原ELISA诊断法。通过阻断性试验、交叉反应试验、敏感性和特异性试验、重复性试验及与病原学方法比较，评价其效果。结果纯化抗原ELISA方法与犬钩虫和蛔虫感染犬血清无交叉反应，检出的阳性血清最高抗体滴度为1：25600，重复性好。结论成功建立犬恶丝虫病ELISA诊断方法，可替代虫检法对犬恶丝虫病进行早期诊断。     

Diagnosis of Fasciola gigantica infection using a monoclonal antibody-based sandwich ELISA for detection of circulating cathepsin B3 protease

A reliable monoclonal antibody (MoAb)-based sandwich enzyme-linked immunosorbent assay (sandwich ELISA) was developed for the detection of circulating cathepsin B3 protease (CatB3) in the sera from mice experimentally infected with Fasciola gigantica and cattle naturally infected with the same parasite. The MoAb 2F9 and biotinylated rabbit polyclonal anti-recombinant CatB3 antibody were selected due to their high reactivities and specificities to F. gigantica CatB3 antigen based on indirect ELISA and immunoblotting. The lower detection limit of the sandwich ELISA assay was 10, 100 and 400 pg/ml, when applied for the detection of rCatB3 antigen and CatB3 in whole body (WB) of newly excysted juveniles (NEJ) and metacercariae (Met) of F. gigantica, respectively. This sandwich ELISA assay could detect F. gigantica infection from day 1 to 35 post infection and revealed that circulating level of CatB3 peaked at day 1 post infection. In contrast, the antibody detection by indirect ELISA could only demonstrate the antibody level from 35 days post infection. The reliability of the assay method was evaluated using serum samples from mice infected with F. gigantica or Schistosoma mansoni, and hamsters infected with Opisthorchis viverrini, as well as normal mice and hamsters. In addition, sera from cattle infected with Paramphistomum cervi, Strongylid, Trichuris sp. and Strongyloides sp., as well as sera from normal cattle were also assessed. In experimental mice, the diagnostic sensitivity, specificity, positive predictive value, negative predictive value, false positive rate, false negative rate and accuracy of ELISA were 95%, 100%, 100%, 97.9%, 0%, 5.3% and 98.5%, while in natural cattle they were 96.7%, 100%, 100%, 98.5%, 0%, 3.4% and 98.9%, respectively. Hence, this assay method showed high efficient and precision for early diagnosis of fasciolosis by F. gigantica.     

Development of an ELISA for esRAGE and its application to type 1 diabetic patients

We recently identified a naturally occurring soluble form of RAGE (the receptor for advanced glycation endproducts, receptor for AGE) in cultured human vascular cells, and named it endogenous secretory RAGE (esRAGE). esRAGE is generated by alternative RNA splicing and is able to capture AGE, and exerts protection against AGE-induced endothelial cell injury. In the present study, the presence of esRAGE in human circulation was demonstrated for the first time, and a highly sensitive and specific sandwich ELISA system for esRAGE was developed to see whether esRAGE could be related to an individual resistance to the development of diabetic vascular complications. Sera from 47 type 1 diabetic subjects without clinical nephropathy (urinary albumin excretion <300mg/g creatinine) and 55 healthy controls were analyzed by the ELISA. Circulating esRAGE concentrations in diabetic patients with simple and proliferative retinopathy (0.09+/-0.02ng/mL, n=16 and 0.08+/-0.02ng/mL, n=8, respectively) were significantly lower than in those without retinopathy (0.13+/-0.06ng/mL, n=23). The results indicate that esRAGE can be a useful biomarker to indicate individual variations in susceptibility to diabetic retinopathy.     

戊型肝炎病毒抗体双抗原夹心法ELISA的建立与初步应用

目的　建立抗戊型肝炎病毒 (HEV)抗体检测的双抗原夹心ELISA(DS -ELISA) ,并应用于多种动物血清的检测。方法　将大肠杆菌表达的一段HEVORF2区重组抗原分别包被微孔板和进行辣根过氧化物酶 (HRP)标记 ,利用 5份阳性血清和 4 0份阴性血清建立双抗原夹心ELISA ;用 4 0 0份义务献血员血清比较双抗原夹心ELISA与间接法IgG抗体ELISA的符合情况 ;用 3只HEV感染猴系列血清比较双抗原夹心ELISA试剂和Genelabs公司HEVIgG试剂 ;用双抗原夹心ELISA试剂检测新疆地区的部分牛、绵羊、山羊、猪血清和上海地区的部分鸡血清中的HEV抗体。结果　建立了检测HEV抗体的双抗原夹心ELISA方法 ,对 4 0 0份义务献血员血清的检测表明其与间接法IgG抗体ELISA试剂的符合情况良好 ,并且有更高的s/co比值 ;与Genelabs公司HEVIgG试剂的比较表明双抗原夹心ELISA试剂的检出更早 ,尤其是持续时间及强度明显优于Genelabs试剂 ;在所检测的各种动物中均发现了HEV抗体 ,其中猪抗体的阳性率最高 ,表明双抗原夹心ELISA试剂可同时用于不同动物的抗HEV抗体检测。结论　利用大肠杆菌表达的HEV重组抗原建立了双抗原夹心法ELISA ,并可同时用于不同动物的抗HEV抗体检测。     

戊型肝炎病毒抗体双原夹心法ELISA的建立与初步应用

目的 建立抗戊型肝炎病毒（HEV）抗体检测的双抗原夹心ELISA（DS-ELISA），并应用于多种动物血清的检测。方法 将大肠杆菌表达的一段HEVORF2区重组抗原分别包被微孔板和进行辣根过氧化物醇（HRP）标记。利用5份阳性血清和40份阴性血清建立双抗原夹心ELISA；用400份义务献血员血清比较双抗原夹心ELISA与间接法IgG抗体ELISA的符合情况；用3只HEV感染猴系列血清比较双抗原夹心ELISA试剂和Genelabs公司HEVIgG试剂；用双抗原夹心ELISA试剂检测新疆地区的部分牛，绵羊，山羊，猪血清和上海地区的部分鸡血清中的HEV抗体。结果 建立了检测HEV抗体的双抗原夹心ELISA方法，对400份义务献血员血清的检测表明其与间接法IgG抗体ELISA试剂的符合情况良好，并且有更高的s/co比较；与Genelabs公司HEVIgG试剂的比较表明双抗原夹心ELISA试剂的检出更早，尤其是持续时间及强度明显优于Genelabs试剂；在所检测的各种动物中均发现了HEV抗体，其中猪抗体的阳性率最高，表明双抗原夹心ELISA试剂可同时用于不同动物的抗HEV抗体检测。结论 利用大肠杆菌表达的HEV重组抗原建立了双抗原夹心法ELISA，并可同时用于不同动物的抗HEV抗体检测。     

Development of an ELISA for detection of antibody in leprosy

An ELISA system was developed for detection of antibodies in leprosy using whole cells of bacteria as an antigen. Whole cells of M. smegmatis, M. vaccae, M. scrofulaceum, M. leprae, C. diphtheriae, and C. xerosis were compared. M. smegmatis was the most reactive against lepromatous sera with OD492 readings 1.5 times and five times higher than the others. In addition, when M. smegmatis were coated to microtiter plates with a volatile ammonium acetate/carbonate buffer and air dried, the antigen coating was found to be three times more reactive than antigen coated with nonvolatile Na borate buffer. Autoclaving M. smegmatis increased the reactivity with lepromatous sera 1.4- to 2.3-fold. M. leprae was found to be 4-10 times more reactive than autoclaved M. smegmatis. Autoclaving M. leprae did not increase reactivity. Antibody titers of some lepromatous sera had endpoint titers of greater than 1:10,000. Both antihuman IgG and antihuman IgA, IgM, and IgG combined conjugates were found to be equally effective in detecting high levels of antibody in patients with multibacillary diseases.     

Two-site sandwich ELISA for detection of Plasmodium vivax blood stage antigens using monoclonal and polyclonal antibodies.

Two systems of sandwich enzyme-linked immunosorbent assay (ELISA), a two-site monoclonal antibody sandwich ELISA MAb-MAb sandwich ELISA) and a two site polyclonal-monoclonal antibody sandwich ELISA (PAb-MAb sandwich ELISA) for the detection of Plasmodium vivax antigens were developed. The assays showed good correlation with the level of parasitemia when tested against serially diluted P. vivax parasites (r = 0.937, and 0.997 for MAb-MAb and PAb-MAb sandwich ELISA, respectively), with the ability to detect as few as 6.68 parasites/10(6) erythrocytes and 2.69 parasites/10(3) erythrocytes, respectively. The MAb-MAb sandwich ELISA was specific, since it was positive only with P. vivax-infected erythrocytes from vivax malaria patients and negative when erythrocytes from 34 healthy individuals and 30 falciparum malaria cases were tested. In contrast, cross-reaction was found in the PAb-MAb sandwich ELISA when the plates were coated with polyclonal IgG and tested against the serially diluted P. falciparum SO strain antigen prepared from in vitro cultures. Comparison between the two systems of two-site sandwich ELISA showed that the MAb-MAb sandwich ELISA was superior to the PAb-MAb sandwich ELISA: (1) it gave a higher sensitivity when tested with serially diluted P. vivax antigen preparations from vivax malaria patients; (2) it gave a higher specificity when tested with the SO strain of P. falciparum from in vitro cultures, (3) it gave a lower absorbance value when tested with erythrocytes from healthy individuals. All 281 cases of vivax malaria already proven by microscopic examination were positive by MAb-MAb sandwich ELISA.(ABSTRACT TRUNCATED AT 250 WORDS)     

A sensitive sandwich ELISA for measuring erythropoietin in human serum

A sandwich, non-competitive enzyme-linked immunosorbent assay (ELISA) for erythropoietin (EPO) is described. The ELISA utilizes a monospecific, polyclonal antibody raised in rabbits against human recombinant EPO (rhu EPO) and purified over a rhu EPO affinity chromatography column. The ELISA procedure can be summarized as follows: Anti-EPO is coated onto 96-well ELISA microtitre plates; standard EPO or sample is added and left to bind to this catching antibody; this is followed by the addition of the same antibody which has been biotinylated; finally, anti-biotin conjugated to alkaline phosphatase is added and the enzyme reaction developed and read at 405 nm. All parameters of the assay have been optimized. Recombinant human EPO was standardized against the World Health Organization 2nd International Reference Preparation for erythropoietin. The minimal detectable concentration of rhu EPO was 0.3-0.5 mU/ml, which corresponded to 1.2-2 mU/ml of EPO in serum (serum diluted 1:4). No reaction was obtained with a variety of blood components and cytokines, indicating that the anti-EPO antibody did not cross-react with those substances to produce false-positive results. The intra-assay variation ranged from 3% to 10%, while the inter-assay variation ranged from 8.5% to 24%. Serum dose-response curves were parallel to the standard dose-response curve. The assay is easy to use, rapid, reproducible, but above all quantitative, specific and sensitive to measure the EPO content in all serum samples.     

新城疫病毒核蛋白单克隆抗体的制备及双抗体夹心ELISA的初步建立

目的制备新城疫病毒(NDV)核蛋白(NP)的单克隆抗体(单抗),并用于建立一种可定量检测NDV病毒含量的双抗体夹心酶联免疫吸附试验检测方法(NDV NP ELISA)。方法基于NDV病毒株F48E9获得NP基因,经原核表达方式制备出重组抗原rNP;免疫小鼠制备NDV NP特异性单抗;单抗经HRP标记和配对筛选,建立NDV NP ELISA,分析其特异性、灵敏度、精密度、准确度和检测线性,并分析本方法定量检测的NP含量与PFU病毒滴度的定量相关性。结果建立基于单抗3C10和4E7的NDV NP ELISA,其定量检测NDV rNP的最佳线性范围为0.015~0.250μg/ml(R2=0.9974),回收率在88.4%~106.01%,变异系数小于3.4%;该方法具有良好特异性;该方法定量检测NDV抗原含量与PFU病毒感染滴度有较好的相关性(R2=0.9209)。结论建立NDV NP ELISA,可准确定量检测NDV病毒中的NP抗原含量,为NDV病毒含量的测定提供一种可靠简便的分析方法。     

Correlation between a sandwich ELISA and an in-vitro bioassay for erythropoietin in human plasma

Summary. A sandwich-type enzyme-linked immunosorbent assay (ELISA) for human erythropoietin (EPO) using two anti-EPO monoclonal antibodies has been compared with an in-vitro EPO bioassay based on CFU-E colony formation in fetal mouse liver cell cultures. In normal subjects and non-uraemic anaemic patients the plasma EPO values estimated with the ELISA correlated well with those by the bioassay, and also inversely with the values of blood Hb, PCV and RBC counts. Dose-response curves for plasma and standard recombinant human EPO in the ELISA were parallel to each other. These results further confirm the validity for the ELISA in measuring circulating human EPO.     

Potential herpesvirus interaction during HIV type 1 primary infection

One hundred twenty-three subjects with documented HIV-1 primary infection were followed for over a year; 96 received highly active antiretroviral therapy (HAART) at recruitment; 27 declined treatment. Fifty uninfected subjects served as baseline controls. HIV-1 viral load, CD4 and CD8 T cell numbers, and serologic changes to Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), human herpesvirus 8 (HHV-8), and cytomegalovirus (CMV) were monitored. Although responses to HAART varied, herpesvirus reactivation frequencies did not differ relative to HIV-1 virologic responses. Forty-seven subjects had reactivations to a single herpesvirus type and 12 subjects to > or =2 types; no single herpesvirus dominated. Antibody seroprevalence to EBV, HHV-6, and CMV were similar but HHV-8 infection was twice as prevalent in HIV-1-infected vs. uninfected individuals. Notably, lower HIV-1 viremia (7,313 vs. 55,548 geometric mean RNA copies/ml) at baseline was significantly associated with HHV-8 seropositivity (p < 0.004).     

测定小鼠细胞因子的双抗体夹心ELISA法的建立及应用研究

目的　建立敏感的测定小鼠IL - 5、IL - 4和IFN -γ水平的生物素 -链霉亲和素双抗体夹心ELISA法 ,并探讨该法在IL - 5转基因小鼠感染模型中的应用价值。方法　含大鼠抗小鼠IL - 4、IL - 5和IFN -γ单克隆抗体的杂交瘤细胞培养上清 ,经PM 10膜超滤、5 0 %饱和硫酸铵沉淀及ProteinG -Sepharose亲和层析纯化。应用活化生物素制剂对纯化的TR FK4、BVD6和AN18单克隆体抗体进行生物素化。用纯化的 2 μg/mlTRFK5、8μg/ml 11B11和 4 μg/mlR4 - 6A2分别作为测定小鼠IL - 5、IL - 4和IFN -γ的包被抗体 ,然后逐步加入样品、生物素化TRFK4 (1μg/ml)、BVD6 (2 μg/ml)和AN18(1μg/ml)、SA -HRPO和OPD ,硫酸终止反应后读取A490 值。结果　所建立的生物素 -链霉亲和素双抗体夹心ELISA法特异性和敏感性高 ,用于检测感染巴西日圆线虫感染的IL - 5转基因小鼠和非转基因小鼠的血清标本取得了较好的效果。结论　该ELISA方法对于测定小鼠细胞因子具有应用价值