Development of an Indirect Enzyme-Linked Immunosorbent Assay for Seromonitoring Contagious Bovine Pleuropneumonia Using Recombinant Lipoprotein LppQ of Mycoplasma mycoides subsp mycoides SC as Antigen

Mycoplasma mycoides subsp mycoides SC （MmmSC） is the etiological agent of contagious bovine pleuropneumonia （CBPP）. The lipoprotein LppQ encoded by lppQ gene is specific to MmmSC and is found in the type strain and in field strains isolated in Europe, Africa, and Australia, as well as in vaccine strains. No serological cross-reactions were observed with the related mycoplasmas of the Mycoplasma mycoides cluster. The N-terminal domain of the mature lipoprotein LppQ is hydrophilic, and it induces a strong, specific, early, and persistent immune response in naturally and experimentally infected animals. Mycoplasma-specific TGA （Trp） codons are utilized as stop codons in most other organisms. The lppQ N-terminal fragment from MmmSC HVRI X strain, the Chinese strain for CF antigen production, was mutated with one-step overlapping extension PCR. Sequence analysis confirmed the successful mutation from A to G in codon 198 in the lppQ gene. The fragment containing the mutation site was subcloned into the pET32a expression vector. The recombinant protein with molecular weight of 42 kDa was purified using the Ni-NTA His.Bind purification kit, with a purity of up to 95%. Western blot indicated that the standard positive serum of CBPP could react with the recombinant protein. The purified protein was diluted to 0.35 μg mL^-1, and coated to microtiter enzyme-linked immunosorbent assay （ELISA） plates. Indirect ELISA reaction conditions were optimized. The value of P/N was determined to be 4.8 （0.934/0.193）, the sensitivity to be 95.8% （46/48）, and the specificity to be 98.9% （161/163）. 3 817 cattle serum samples from three different provinces were detected by the indirect ELISA and CFT. The Kappa value is 0.63, which is middle or high agreement between the two methods.

Detection of Atrazine Residue in Food Samples by a Monoclonal Antibody-based Enzyme-linked Immunosorbent Assay

Atrazine（AT,2-chloro-4-ethylamino-6-isopropyl-amino-s-triazine）has been detected in ground water in several areas of the United States for many years,as well as in China,wherein the growth rate of its gross

A Comparison of Enzyme-Linked Immunosorbent Assay versus Multiplex Methodology Using an <i>in Vitro</i>Model of Pulmonary Hypertension and Inflammation

Enzyme-linked immunosorbent assay (ELISA) is the most widely used method for measuring a single cytokine. Recent developments in cytokine quantification such as multiple arrays measure multiple cytokines simultaneously. Although good correlations between ELISA and multiplex methods have been observed, side by side comparisons are limited. In the present study we hypothesized that ELISA and Luminex techniques are comparable in detecting cytokines in culture medium when pulmonary artery smooth muscle cells (PASMC) are exposed to stress. Primary human PASMC were cultured in modular chambers and exposed to 21% FiO2 and peak inspiratory and positive end expiratory pressure of 24 and 8 cmH2O respectively, and 95% FiO2. At 24 hours, culture medium was collected and assayed for interleukin-6 (IL-6) and IL-8 by quantitative ELISA and by Human Cytokine 25-Plex Panel using a Luminex 200 analyzer. A comparative analysis of agreement between our ELISA and Luminex data was detailed for control and stress conditions using the Bland-Altman plot analysis. Each assay resulted in comparable increased (p < 0.001) levels of IL-6 and IL-8 as compared to control in response to oxidative and biophysical stress. The Bland-Altman analysis demonstrated that 95% of the differences between ELISA and Luminex values were within ±1.96 SD from the mean difference indicated by the 95% limits of agreement for the measurements of IL-6 and IL-8. There was no systematic bias as a function of inflammation level. We conclude that in this cell culture model, ELISA and Luminex are comparable in detecting the levels of IL-6 and IL-8 in the culture medium. If measurements of multiple cytokines are demanded and the amount of sample is limited, Luminex multi-analyte profiling technology is accurate and sensitive.

Development of a recombinant pB602L-based indirect ELISA assay for detecting antibodies against African swine fever virus in pigs

African swine fever(ASF),caused by the African swine fever virus(ASFV),is a devastating disease of domestic and wild pigs.There is no effective vaccine,and the control of the disease relies mainly on surveillance and early detection of infected pigs.Previously,serological assays,such as ELISA,have been developed mainly based on recombinant structural viral proteins of ASFV,including p72,p54,and p30.However,the antibodies against these proteins do not provide efficient protection against ASFV infection in pigs.Therefore,new serological assays that can be applied for clinical diagnosis and evaluating serological immune response in vaccinated pigs are still required.In this study,we expressed and purified a recombinant p B602 L protein.The purified p B602 L protein was then used as an antigen to develop an indirect ELISA assay.This assay has no cross-reaction with the anti-sera against the 15 most common pig pathogens in China,such as classical swine fever virus,pseudorabies virus,and porcine parvovirus.This assay and a commercial ELISA kit were then used to detect 60 field pig serum samples,including an unknown number of antiASFV sera.The coincidence of the two assays was 95%.Furthermore,the p B602 L-based ELISA was employed to test the antibody responses to the seven-gene-deleted ASFV strain HLJ/18-7 GD in pigs.The results showed that the antibody levels in all vaccinated pigs,starting from the 10 th day post-inoculation,have increased continuously during the observation period of 45 days.Our results indicate that this p B602 L-based indirect ELISA assay can be employed potentially in the field of ASFV diagnosis.

基于VP6蛋白的牛轮状病毒抗体间接ELISA检测方法的建立与应用

为了建立牛轮状病毒(BRV)血清抗体的检测方法,从病料中克隆牛轮状病毒VP6基因,构建其表达载体,利用原核表达技术表达重组VP6蛋白,建立牛轮状病毒血清抗体间接ELISA检测方法。结果显示,重组VP6蛋白大小为40 ku,以包涵体形式表达,Western blot证实重组VP6蛋白有良好的反应原性;以4μg/mL浓度的抗原包被酶标板,一抗血清50倍稀释,酶标二抗稀释10000倍稀释,为最佳工作条件,阴阳临界值为0.233,表明该方法具有良好的特异性和敏感性。建立的检测BRV抗体的间接ELISA可用于临床BRV感染的检测。

Establishment and Application of an Indirect ELISA for Detection on Antibody of Haemophilus parasuis

[Objective]The aim was to establish an indirect ELISA for detection on antibody of Hps. [Method] The optimal conditions of indirect ELISA were selected and determined based on heat-resistant serotype 4 and 5 of Hps; specific,repeating and sensitive tests were conducted and 200 serums were detected. [Result]The optimal conditions were as follows： coating concentration of antigen at 10 μg /ml,and coating for 2 h at 37 °C; PBST containing 20 g /L of skim milk powder as blocking fluid for 30 min; serum dilution at 1∶ 80; reaction time of antigen for 45 min; dilution of secondary antibody at 1∶ 12 000 and effecting for 30 min; color development reaction for 15 min. [Conclusion] The established indirect ELISA is good in specificity and repetitiveness with higher sensitivity than that of indirect hemagglutination test; the results of clinic samples （ negative /positive serums） were in consistent with those detected with foreign ELISA kits. The established method can be made use of in serum antibody of Hps de- tection and seroepidemiology study.

Determnation of ochratoxin A in grain by monoclonal antibody－based enzyme－linked immunosorbent assay

The simple rapid and sensitive enzyme-linked immunosorbent assay (ELISA) methods, di-rect and indirect ELISA, for quantitation of ochratoxin A in cereal had been developed by theutilization of monoclonal antibody on immunomicroplate. Direct FLIAS was found to be less timeconsuming than indirect ELISA. For direct FLISA, recovery of 1 -500 ppb OA added to wheat was78.9-100.0% and rice was 88.9- 120.0%. For indirect EI.IAS, recovery of 1-500 ppb OA addedto wheat was 79.0- 110.0% and rice was 82.0 120.0%. The minimal detection level for OA was Ippb. Analyses of 31 samples that caused humanintoxicant for OA showed that the ELISA resultsagreed wtll with those obtained by thin-layer chromatogrdphy.

Microcystin-LR detection based on indirect competitive enzyme-linked immunosorbent assay

Microcystins(MCs)are a group of closely related toxic cyclic heptapeptides produced by common cyanobacte-ria,which cause lots of accidents and threatens human health.In this paper,an indirect competitive enzyme-linked immu-nosorbent assay(ic-ELISA)was established and used to detect microcystin-LR(MC-LR)in drinking and surface waters.The concentration of coating antigen was 5 mg/mL,the dilution of monoclonal antibody MC10E7 was 1:3000,the dilution of enzyme tracer(goat anti-mouse IgG-peroxidase)was 1:3000,the standard concentration of MC-LR ranged from 0.001 mg/L to 30 mg/L,and o-phenylenediamine was used as substrate.The assay showed high relativity with high performance liquid chromatography(HPLC)with a correlation coefficient of more than 99%.The relative standard deviation was less than 10%,the detection limit was achieved down to 0.01 mg/L and up to 5.1 mg/L.The quantitative detection range was from 0.03 mg/L to 3 mg/L,and the antibody had high specificity for[4-arginine]microcystins.It performed well in spite of the influence of the real samples.

Development of ELISA and immunochromatographic assay for ofloxacin

Two rapid, sensitive and reliable immunoassay methods, namely competitive indirect enzyme-linked immunosorbent assay (CI-ELISA) and colloidal gold-based immunochromatographic assay (CGIA), were developed to detect ofloxacin (OFL). The linear range of the CI-ELISA was from 0.5 to 128 ng/mL with a limit of detection (LOD) of 0.35 ng/mL. Good recoveries were obtained in analyzing simulated swine urine samples. The CGIA could accurately estimate OFL at concentrations as low as 10 ng/mL in less than 10 min, and test results were read visually without any instrument.

大熊猫源犬细小病毒VP2基因的原核表达及间接ELISA检测方法的建立

【目的】建立一种检测大熊猫血清中犬细小病毒(canine parvovirus,CPV)抗体的间接酶联免疫吸附剂测定(enzyme linked immunosorbent assay,ELISA)方法。【方法】以大熊猫源CPV DNA为模板,利用PCR扩增VP2基因,再用原核表达系统对VP2基因进行表达,经纯化后的蛋白作为ELISA包被抗原;制备并纯化兔抗大熊猫IgG,采用辣根过氧化物酶(horseradish peroxidase,HRP)标记作为间接ELISA酶标二抗,通过棋盘法确定抗原包被质量浓度及血清稀释度等条件,并评估建立方法与商业试剂盒检测样品结果的符合率。【结果】原核表达成功获得约70 ku的VP2蛋白,将其作为间接ELISA包被抗原,抗原最佳包被质量浓度为2.0μg/mL,血清最佳稀释度为1∶400,用该方法进行检测血清样品时OD450≥0.258为阳性,反之为阴性。采用建立的ELISA方法检测大熊猫血清样本阳性率为60.0%,高于商业化检测试剂盒检测的阳性率(52.5%),两者总符合率达到87.5%。【结论】本研究首次建立了基于大熊猫源CPV VP2蛋白为抗原、自制HRP标记兔抗大熊猫IgG为酶标二抗的间接ELISA方法,该方法特异性强、灵敏性较高、重复性好,为大熊猫血清中CPV抗体的检测提供了技术支持。

猪肉中2-(三氟甲基)吩噻嗪的Ic-ELISA检测

为了快速检测猪肉中的镇静剂2-(三氟甲基)吩噻嗪(2-(trifluoromethyl)phenothiazine,TFPTZ),分别用偶氮苯甲酸法、混合酸酐法合成了半抗原、完全抗原,通过免疫新西兰大耳白兔获得了多克隆抗体,采用间接竞争酶联免疫方法(Ic-ELISA)对猪肉中TFPTZ进行了定量分析,实验条件:包被抗原浓度1.25μg/mL,多克隆抗体稀释16000倍,37℃包被3 h,封闭液为质量分数1%的牛血清白蛋白(BSA),TFPTZ稀释液为含体积分数10%的DMSO的PBS,竞争反应60 min.该方法相关系数R^(2)为0.9991,IC_(50)为1.5002μg/L,最低检测限IC_(10)为0.2841μg/L,线性(IC_(20)~IC_(80))为0.4307~5.2252μg/L,与5种TFPTZ结构类似物的交叉反应率小于1.2%,样品添加回收率为93.26%~109.13%,变异系数小于6%,实际样品检测结果与高效液相色谱法测定结果高度一致,表明建立的快速检测猪肉中TFPTZ的Ic-ELISA方法具有良好的准确度,适用于快速检测猪肉中TFPTZ的残留量.

莫米松糠酸酯高特异性抗体制备及酶联免疫分析方法

莫米松糠酸酯(mometasone furoate,MF)是一种常见的糖皮质激素。为快速、便捷地监控MF的滥用情况,制备了MF单克隆抗体并建立了其竞争酶联免疫检测方法。将氨氧乙酸分别连接至MF和莫米松二糠酸酯(mometasone difuroate,MDF),合成了免疫半抗原和包被半抗原。免疫半抗原以活泼脂法连接钥孔血蓝蛋白获得全抗原,通过免疫小鼠、细胞融合及筛选获得能够稳定分泌抗MF单克隆抗体的细胞株,制备并纯化了抗体。该抗体的主要识别区域为MF的五元环区域,因此不和常见的64种糖皮质激素发生交叉反应。建立了基于异源包被的MF间接竞争酶联免疫检测法,其半抑制浓度(IC_(50))为1.2 ng/mL,对肌肉和肝脏的最低检出限分别为0.52μg/kg和0.59μg/kg。灵敏度相比于同源包被提升了20倍。使用60%甲醇水溶液提取动物组织的添加回收率为70%~82%。该方法能有效应用于动物组织中MF的快速筛查。

凡纳滨对虾红体病病原菌间接ELISA快速检测方法的研究

以凡纳滨对虾红体病病原菌副溶血弧菌为抗原,免疫兔获得高免血清,建立一种快速检测凡纳滨对虾红体病病原菌副溶血弧菌的ELISA技术。采用棋盘滴定法确定抗原和抗血清的最适工作浓度分别为106CFU·mL-1和1∶2000;病原菌检测灵敏度为每孔104CFU;抗血清与其它细菌标准菌株的交叉反应结果均呈阴性;阻断实验中的阻断率达75.88%;交叉反应和阻断实验结果表明该方法具有较高的特异性。将该方法标准化后检测了30份人工感染后的凡纳滨对虾和健康凡纳滨对虾,阳性检测率分别为93.3%和13.3%,表明该技术不仅能够检测已发病的凡纳滨对虾,而且能够检测带菌的凡纳滨对虾,这对于水产养殖业中疾病的早期诊断有着重要意义。

间接竞争ELISA法测定稻田土壤中除草剂毒莠定的残留量

通过对反应体系中酶标二抗（辣根过氧化物酶标记羊抗兔IgG）和抗体的最佳稀释浓度等条件的筛选和确定,最终建立了一种快速灵敏地测定污染稻田土壤中毒莠定残留量的方法--间接竞争ELISA分析方法.结果表明,酶标二抗和抗体的最佳稀释度均为1：500（体积比）,毒莠定的检出下限达到5 ng·mL^-1,在0.07～0.7μg·mL^-1浓度范围内有良好的线性;土壤浸出液加样的平均回收率为104.11%,变异系数在3.13%～11.13%之间,符合农药残留分析的要求;样品基质对检测结果没有干扰.

检测猪肺炎支原体抗体间接ELISA方法的建立

选用猪肺炎支原体Mhp J株培养物制备抗原,建立检测猪肺炎支原体抗体的间接ELISA(酶联免疫吸附)方法。结果显示,ELISA试验的最佳反应条件为:抗原包被浓度为1.5μg/ml,待检血清的最佳稀释浓度1∶100,2%明胶作封闭液,抗原抗体最佳结合时间为90 min,酶标抗体1∶10 000(体积比)稀释,最佳作用时间为60 min。对136份样品检测结果表明,建立的猪肺炎支原体间接ELISA抗体检测方法与美国IDEXX公司生产的猪肺炎支原体抗体检测试剂盒检测的符合率达到83.8%,假阴性率8.8%,假阳性率1.5%。

应用间接ELISA检测鸡痘病毒抗体方法的建立

应用鸡胚成纤维细胞(CEF)扩增鸡痘病毒(Fowlpox virus,FPV)并提纯后作为抗原建立了具有较高特异性和灵敏性的间接ELISA方法.通过方阵滴定法来确定抗原最佳包被浓度为2.7μg/孔,待检血清最佳稀释倍数为1:100,其阳性临界值为OD≥0.113.将400份FPV免疫实验鸡血清用本方法进行检测,其阳性检出率为81.25%(325/400).此外,将该方法与琼脂扩散试验进行比较检测血清样品,结果显示本方法的灵敏度比琼脂扩散试验灵敏400～800倍,而且还有特异性强,操作简便、快速等优点.

重组蝎毒抗神经兴奋肽的ELISA分析方法建立及稳定性的初步研究

目的建立重组蝎毒抗神经兴奋肽（ANEP）的ELISA分析方法并对ANEP的稳定性进行初步研究。方法以分别建立的间接ELISA和间接竞争ELISA分析方法进行ANEP含量测定，并通过方法学的优化，最终以建立的间接法ELISA方法测定了温度、pH值、反复冻融、超声对ANEP稳定性的影响。结果间接ELISA相对于间接竞争ELISA有着更好的线性关系和灵敏度，线性范围0.025-1.60μg／mL。检测限为10ng／mL。稳定性实验表明ANEP在37，60℃的条件下放置24h含量基本不变，pH5-11的缓冲液中保持稳定，反复冻融、超声4min后含量降低。结论所建立的间接ELISA方法能很好的用于ANEP的测定。ANEP的热稳定性较好，强酸性下不稳定，对反复冻融与超声等稳定性较差。

基于酶联免疫分析方法检测畜禽饲料中恩拉霉素

本文建立了一种应用于检测畜禽饲料中恩拉霉素的间接竞争酶联免疫分析法。采用羰基二咪唑法将生物活性高的恩拉霉素A组分合成的半抗原偶联卵清蛋白,构建检测原;同时将杂交瘤细胞株2H1F91免疫BALB/c小鼠,制备特异性识别恩拉霉素的单克隆抗体。在此基础上,构建了恩拉霉素的间接竞争酶联免疫分析法的标准曲线,该曲线IC_(50)为91.61ng/mL,线性范围为25.73~471.39ng/mL,检出限为13.11ng/mL。猪饲料样品的添加回收率为91.60%~95.75%,鸡饲料的添加回收率为89.33%~94.80%,并且二者的变异系数均低于12%,这表明建立的方法结果可靠,适用于畜禽饲料中恩拉霉素含量的快速检测。

基于兔出血症病毒衣壳蛋白优势抗原区的间接ELISA方法建立

为建立一种检测兔出血症病毒（Rabbit hemorrhagic disease virus,RHDV）抗体的间接ELISA方法,首先扩增了VP60的优势抗原区A（31～250 aa）和B（470～579 aa）两个片段,然后应用融合PCR方法将A、B片段连接起来,克隆至pET-30a（＋）,转染BL21感受态细胞,进行原核表达。用Western blot方法对表达产物（AB）的免疫原性进行鉴定,再以纯化的AB为诊断抗原,通过对抗原-抗体反应条件的多重优化,建立检测RHDV抗体的间接ELISA方法。试验结果表明,本研究成功表达了RHDV VP60的优势抗原区（AB）,重组蛋白的分子量约为36 kDa,该蛋白能与RHDV抗体发生特异性反应。以纯化的AB为包被抗原,成功建立了检测RHDV抗体的间接ELISA方法。经过对部分田间样品的检测和应用,证明该方法具有特异性强、重复性好、敏感性高等优点。本研究为将来开展RHDV的流行病学调查和疫苗研究等提供了良好的技术手段。

食品中黄曲霉毒素M_(1)的间接竞争酶联免疫法的建立

该文建立一种间接竞争酶联免疫法(indirect competitive enzyme-linked immunosorbent assay,ic-ELISA)快速测定食品中黄曲霉毒素M_(1)(aflatoxin M_(1),AFM_(1))的分析方法。AFM_(1)标准品用甲醇稀释,AFM_(1)标准品与AFM_(1)全抗原竞争结合AFM_(1)单克隆抗体,利用3,3′,5,5′-四甲基联苯胺(3,3′,5,5′-tetramethylbenzidine,TMB)单组分显色液显色后,酶标仪测定吸光度。在优化好的条件下,浓度范围为9.743~2.605×10^(3)pg/mL时具有良好的线性关系,相关系数(determination coefficient,R^(2))为0.9927,检出限IC_(10)为3.84 pg/mL,加标回收率为88.43%~105.75%。该方法适用性好、操作简单、灵敏度高,满足食品中AFM_(1)分析检测的需求。