SERODIAGNOSIS OF CLONORCHIASIS BY ENZYME—LINKED IMMUNOSORBENT ASSAY WITH HRP—SPA

In thes paper the authors used the Horseradish peroxidase labelledstaphylococcal protein A(HRP—SPA)in ELISA,for the detection of Clo-norchis sinensis infection.Serum tests were made on 116 confirmed cases ofclonorchiasis,103(88.8%)of them showed positive,while only 6(4.4%)werepositive among 138 healthy people.Samples were collected on filter paperstrips,111(95.7%)cases were positive among 116 comfirmed cases tested,but only 2(1.5%)were positive out of 138 healthy persons.The resultswere similar to those obtained by sheep antihuman IgG.Animal experimentalso showed that the SPA—ELISA can be used for the diagnosis ofclonorchiasis.In an endemic area,stool egg positive rate was 8.8%(62/703).whenchecked with SPA—ELISA,the rate of conformity in both filter paperstrips and stool examinations was 90.3(56/62).Among 641 serum testsfrom individuals negative in stool examinations,only 35(5.5%)reactedpositively.The authors suggested—that SPA—ELISA with soluble Clo-norchis antigens could be used in a large scale seroepidemiological surveyin endemic areas.

Construction and Expression of Tp0453 Recombinant Protein of Treponema pallidum and Development of Indirect ELISA for Diagnosinq Syphilis

Objectives： To clone and express Tp0453 outer membrane protein of Treponema pallidum, and to evaluate its significance in the serodiagnosis of syphilis. Methods： The immuno-dominant epitope of Tp0453 gene was amplified from the complete genome of T.pallidum by polymerase chain reactions （PCR）, subcloned into the expression vector Pqe32 to generate recombinant plasmid Pqe32/Tp0453, and was then expressed in E. coli M15. The fusion protein was purified with Ni-NTA affinity purification. Indirect ELISA was developed to detect human serum IgG antibody to T. pallidum. Results： The recombinant Tp0453 protein was successfully expressed and purified. The recombinant protein had a molecular weight of approximately 32KDa.Indirect ELISA to the recombinant protein was developed.Sixty control sera were tested by ELISA and yielded a sensitivity of 100% （30/30） and a specificity of 100% （30/30）. While testing for T. pallidum in human sera, the sensitivity and specificity of ELISA were 96.8% and 100%, respectively, when compared with TPPA test results. The concordance of results between the ELISA test and the TPPA test was 98.2%. Conclusion： The recombinant Tp0453 outer membrane protein elicited a strong immunoreaction to anti-T.pallidum IgG antibody and has great potential use in ELISA for the serodiagnosis of syphilis.

Changes of p53 protein blood level in esophageal cancer patients and normal subjects from a high incidence area in Henan,China

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Development and evaluation of immunoassay for zeranol in bovine urine

A high affinity polyclonal antibody-based enzyme linked immunosorbent assay （ELISA） was developed for the quantification of zeranol in bovine urine. On the basis of urine matrix studies, the optimized dilution factors producing insignificant matrix interference were selected as 1：5 in pretreatment. In the improved ELISA, the linear response range was between 0.02 and 1 μg/ml, and the detection limit was 0.02 μg/ml for the assay. The overall recoveries and the coefficients of variation （CVs） were in the range of 82%-127% and 3.5%-8.8%, respectively. Thirty-six bovine urine samples spiked with zeranol （ranging from 0.2 to 10 μg/ml） were detected by the ELISA and liquid chromatography （LC） method, and good correlations were obtained between the two methods （R^2=0.9643）. We conclude that this improved ELISA is suitable tool for a mass zeranol screening and can be an altemative for the conventional LC method for zeranol in bovine urine.

Development of an Indirect ELISA Using Recombinant Truncated Envelope Glycoprotein for Detection of Antibodies against Japanese Encephalitis Virus

[ Objective] To develop an indirect ELISA assay for detecting antibodies against envelope glycoprotein （ E protein） of Japanese encephalitis virus （JEV）. [ Method] Specific primers were designed according to JEV sequences published in the GenBank. The cDNA of JEV E gene （about 1 000 10p） was amplified by the RT-PCR with the specific primers. After sequencing analysis, the E gene was cloned into pET30a expression vector and expressed in E. coli BL21 （DE3） with the induction of IPTG. After denaturation, purification and renaturation, the recombinant protein was analyzed by the SDS-PAGE and the westem blotting. An indirect ELISA was developed to detect antibodies against JEV. [ Result] The E protein was mainly expressed in inclusion body. With the purified E protein, the indirect ELISA was developed and displayed good specificity, sensitivity and repeatability, [ Conclusion]The developed ELISA using the truncated E protein as antigen is a simple, convenient and rapid serological method for diagnosis, monitoring antibody level and epidemiological investigation of JEV.

Development of PPA-ELISA for Detecting Antibodies against Porcine Pseudorabies Virus Using Truncated Recombinant Glycoprotein gD Expressed in E.coli

The purpose of this study was to develop a method for detecting antibodies against porcine pseudorabies virus （PRV）. According to the published genomic sequence of PRV SA strain, an approximately 1 070-bp gD gene fragment was amplified by PCR. The PCR products were cloned into the prokaryotic expression vector pET30a and the positive recombinant plasmid was transformed into E. coli BL21. Through induction with IPTG, the recombinant gD protein was expressed as inclusion bodies. As analyzed by western blot assay, the purified recombinant gD protein had good antigenicity and high specificity. Using the purified gD protein as coating antigen and horseradish peroxidase labeled staphylococcal protein A （PPA） as secondary antibody, we developed a PPA-ELISA for detecting antibodies against porcine PPV. No cross-reaction with the positive sera against seven common pathogens in pigs including classical swine fever virus, porcine parvovirus, porcine reproductive and respiratory syndrome, Japanese encephalitis virus, porcine circovirus type 2, porcine epidemic diarrhea virus, transmissible gastroenteritis virus was observed. The repeatability test showed that the intra- and inter-assay coefficients of variation were lower than 5% and 10%, respectively. Compared with the ELISA gD antibody test kit produced by IDEXX, the coincidence, sensitivity and specificity of the developed PPA-ELISA were 92.0%, 95.1% and 88.1%, respectively. The developed PPA-ELISA had good repeatability, sensitivity and specificity and was a rapid and simple serological method for surveillance of PRV antibodies in pig herds as well as for rapid diagnosis and epidemiological investigation of PRV infection.

猪增生性肠病间接ELISA抗体检测试剂盒的研制与应用

【目的】研制一种检测胞内劳森菌(Lawsonia intracellularis,LI)抗体的间接ELISA试剂盒,为LI的监测和疫苗评价提供工具。【方法】表达并纯化LI的外膜蛋白Omp2,以其为包被抗原建立检测LI抗体的间接ELISA方法,优化ELISA反应条件;用建立的ELISA方法检测稀释的LI阳性血清来评价试剂盒的敏感性,检测其他病原的阳性血清来评价试剂盒的特异性;试制3批试剂盒,制定试剂盒的敏感性和特异性检验标准,测定试剂盒在4℃的保存期;用试制的试剂盒检测LI阴性和阳性质控血清,研究试剂盒的成立条件;通过对不同时间和猪场采集的1 000份临床猪血清样本的检测来评价该试剂盒的实用性;用本试剂盒与进口商品化试剂盒平行检测LI阳性和阴性血清各50份以评价试剂盒的符合率。【结果】成功表达并纯化了Omp2蛋白,蛋白纯度为90.31%,在Western blot试验中可以与LI阳性血清发生反应。ELISA最佳反应条件为:Omp2以200 ng/孔4℃包被12-16 h;血清1﹕50稀释,37℃孵育30 min;羊抗猪Ig G-HRP 1﹕20 000稀释,37℃孵育30 min;TMB底物37℃显色15 min,用0.5 mol·L^(-1)的硫酸终止反应。该试剂盒检测LI阳性血清的最高检出倍数为8,敏感性较好;试剂盒检测E.coli、App、Mhp、SS2、PRRSV、PRV的结果均为阴性,特异性较好。制定了试剂盒的敏感性和特异性检验标准。试剂盒在4℃可保存15个月。试剂盒的成立条件为:阳性标准血清OD_(450nm)≥1.25,阴性标准血清OD_(450nm)<0.3。试制的试剂盒批内、批间重复性试验变异系数均小于10%。与国外商品化ELISA检测试剂盒对比的符合率达86%。用试制的ELISA试剂盒检测1 000份华东部分地区临床猪血清样品,其中LI阳性检出率为59.90%,表明LI在华东地区猪群中普遍存在。【结论】本研究开发的LI间接ELISA抗体检测试剂盒特异性高,灵敏度高,与商品试剂盒符合率高,可用于临床LI抗体的检测。

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。

山羊源贝氏柯克斯体抗体间接ELISA检测方法的建立与应用

为建立山羊源贝氏柯克斯体(Coxiella burnetii)抗体间接ELISA检测方法,对贝氏柯克斯体的com1基因进行克隆及原核表达,以com1纯化蛋白作为抗原,建立间接ELISA检测方法,并对临床收集的血清样本进行检测。结果显示,重组蛋白大小为27 ku,经Western blot鉴定com1蛋白反应原性良好;ELISA检测方法抗原包被量为4μg/mL,血清的稀释倍数为1∶100,酶标二抗稀释倍数为1∶2500,阴阳临界值为0.278。用该方法对流产衣原体、山羊支原体、牛支原体阳性血清进行检测,均为阴性;当C.burnetii阳性血清稀释至2048倍时检测结果仍为阳性;批内、批间变异系数均小于10%。用该方法对陕西省部分羊场收集到的307份血清样本进行检测,样本阳性率为9.12%。成功建立了一种检测贝氏柯克斯体抗体的间接ELISA检测方法,这为C.burnetii引起的Q热的实验室诊断和流行病学调查提供了技术支持。

Detection of Antibodies against Toxoplasma gondii by ELISA with Recombinant Microneme Protein 3

[Objective] To develop a new method for serodiagnosis of swine toxoplasmosis. [Method] With the purified recombinant microneme protein 3 （rMIC3） as coating antigens, an indirect ELISA was developed for detection of antibodies against Toxoplasma gondii. [ Result] The optimal working concentration of rMIC3 was 3. 40 ug/ml, and the optimal degree of dilution of sera was 1：160. Cross-reaction was not observed between the Toxoplasma gondii-positive sera and the positive sera against classical swine fever virus or some other pathogens. The developed ELISA had 92.56% coincidence rate with latex agglutination test. [ Conclusion] The developed ELISA is sensitive, rapid, specific and reproducible, and thus it can be applied in serodiagnosis and seroprevalence investigation of swine toxoplasmosis.

A NEW QUANTITATIVE DETECTION METHOD OF RECOMBINANT CFP10-ESAT6 AMALGAMATION PROTEINS FROM MYCOBACTERIUM TUBERCULOSIS BASED ON MICRO-MAGNETIC PROBES STRATEGY

A new rapid,specific and sensitive method for assay of recombinant CFP10-ESAT6 amalgamation proteins from Mycobacterium tuberculosis was proposed.The method used streptavidincoated magnetic beads to enrich the specific biotinylated anti-CFP10 antibody,then adopted a sandwich-type enzyme linked immunosorbent assay technology with two kinds of monoclonal antibodies:biotinylated anti-CFP10 antibody and HRP-labeled anti-CFP10 antibody to identify the target CFP10-ESAT6 proteins,and finally detected chemiluminescence intensity by a small home-made optical sensor.It was shown that,the corresponding chemiluminescence intensity had a good logarithmic linear response to the concentration of CFP10-ESAT6 proteins when ranging at 1~1000 ng/mL,and the correlation coefficient is 0.9937.The proposed method could detect the CFP10-ESAT6 proteins with low detection limit(1 ng/mL)and the detection time could be controlled within 45 min.Compared with commonly used detection methods of M.tuberculosis,this method was easy to operate,faster,and of higher sensitivity.The achievement of the quantitative detection of CFP10-ESAT6 proteins has important scientific significance and wide application prospects in tuberculosis control.

Study on matrix metalloproteinase-2, 9 in peri-implant sulcular fluid

Objective: To study the expression of matrix metalloproteinases-2, 9 (MMP-2, MMP-9) of healthy implant and peri-implant sulcular fluid (PISF) by enzyme-linked immunosorbent assay (ELISA) method, and evaluate the level of MMP-2 and MMP-9 in sulcular fluid as an objective indicator of tissue inflammation around implants. Methods: A total of 40 implants were selected from 30 patients who were treated with dental implants and were divided into two groups: the inflammatory group and the healthy control group with 20 pieces respectively. ELISA double antibody sandwich method was used to detect the levels of MMP-2 and MMP-9 in PISF. Results: The MMP-2 and MMP-9 expressions were significantly different between the healthy implant group and the peri-implant group (p < .05). The concentration of MMP-2, MMP-9, and the amount of sulcular fluid in the inflammatory implant group were positively correlated with the clinical parameters (probing depth [PD], modified sulcus bleeding index [mSBI]). Conclusions: Under physiological conditions, the levels of MMP-2 and MMP-9 were low. When the periodontal tissue was stimulated by inflammation, the expression levels of MMP-2 and MMP-9 were increased, which could reflect the severity of inflammation. The increase levels of MMP-2 and MMP-9 in PISF could better reflect the health status of peri-implant tissues, which could be used as an objective indicator to assist in the diagnosis of peri-implant inflammation.

Concerns arise: wheat allergy risk in pre-packaged food products from China

Understanding and monitoring the cross-contamination of food allergens is crucial for safeguarding public health and ensuring food safety.Food allergen risk assessment,derived from classical toxicological principles,can identify and quantify the risk of allergies.This study aimed to investigate the risk of wheat allergic reactions to prepackaged foods from China through the utilization of food allergen risk assessment.A total of 575 products have been surveyed,wheat/gluten,milk and egg were major allergens labelled on products.According to voluntary incidental trace allergen labelling 3.0(VITAL®3.0)program,the number of products belonged to Action Level 2 were 303.Integration of precautionary allergen labeling(PAL)analysis indicated that 9.57%products would pose a potential risk to wheat allergic individuals.The probabilistic risk assessment results suggest that 7984 allergic reactions may arise among wheat-allergic consumers during 10000 eating occasions due to the consumption of pre-packaged food products with incorrect wheat-related allergen labelling.This study demonstrated that a risk assessment-based approach can support the guidance of allergen labelling and management of food allergen for pre-packaged food products,providing protection for allergic individuals in food consumption and for food manufacturers in food production and trade.

上海市松江区猪口蹄疫病毒3ABC抗体血清学调查

为摸清上海市松江区2020-2022年猪口蹄疫感染情况,采集有代表性的规模场和专业户的猪血清样品共1 505份,采用酶联免疫吸附试验(ELISA)方法进行猪口蹄疫病毒非结构蛋白3ABC抗体检测,结果阳性样品32份,阳性率2.13%。规模场、专业户阳性率分别为1.16%、3.78%。

新霉素ELISA检测方法的建立

目的:比较直接和间接竞争酶联免疫法(enzyme linked immunosorbent assay,ELISA)的优缺点,建立新霉素残留ELISA检测方法。方法:利用自制的新霉素多克隆抗体,采用直接竞争和间接竞争ELISA方法检测新霉素残留,并比较两种方法的优缺点。结果:新霉素抗血清和庆大霉素的交叉反应率为2.04%,和卡那霉素的交叉反应率为0.02%,和氨苄青霉素、红霉素、四环素的交叉反应率均小于0.01%。初步测试新霉素间接竞争ELISA法的准确性和回收率。板内误差小于4%,板间误差小于11%,回收率为135.5%～191.3%。直接竞争和间接竞争ELISA方法的检测极限分别为28.58ng/mL和51.74ng/mL,达到了国家对新霉素规定的500μg/kg MRL检测限。结论:建立了直接竞争和间接ELISA吸附检测方法,条件优化更成功的间接竞争ELISA可用于开发新霉素检测试剂盒。

双抗原夹心ELISA法检测马尔尼菲青霉Mp1p抗体

目的建立一种检测马尔尼菲青霉特异性抗体的双抗原夹心ELISA方法。方法利用毕赤酵母系统表达重组马尔尼菲青霉特异性甘露糖蛋白Mp1p,并利用改良过碘酸钠法标记Mp1p,经棋盘滴定法建立一种可检测马尔尼菲青霉Mp1p特异性抗体的双抗原夹心ELISA法,并检测100例健康人群对照血清、21例血培养确诊其他真菌感染病人血清和15例血培养确诊马尔尼菲青霉病人血清,联合本实验室前期建立的马尔尼菲青霉抗原检测方法评价其临床应用价值。结果成功建立一种检测马尔尼菲青霉Mp1p特异性抗体的双抗原夹心ELISA法,经健康人群对照及其他真菌感染病人血清评价特异度为100%(121/121),检测15例马尔尼菲青霉病人血清,Mp1p特异性抗体2例阳性,Mp1p特异性抗原12例阳性,Mp1p抗体与抗原联合检测可明显提高灵敏度,达到93.3%(14/15)。结论双抗原夹心ELISA法检测马尔尼菲青霉Mp1p特异性抗体具有高度的特异性,联合抗原检测可提高马尔尼菲青霉感染诊断率。

双抗夹心ELISA检测食品中大肠杆菌O157:H7方法研究

研究获得纯化抗大肠杆菌O157:H7IgY抗体,经检测10mg/ml纯化IgY抗体的效价为1:320;以大肠杆菌O157:H7免疫新西兰大耳白兔,获得兔抗大肠杆菌O157:H7IgG抗体,效价达1:25600。以兔抗大肠杆菌O157:H7IgG抗体稀释3200倍作为捕获抗体,抗大肠杆菌O157:H7IgY抗体为检测抗体建立双抗夹心ELISA方法检测大肠杆菌O157:H7,正交试验分析表明,捕获抗体于37℃包被2h、不封闭、抗原与捕获抗体于37℃结合2h、检测抗体浓度为0.25mg/ml、与抗原于37℃结合1h为最优反应条件。该方法对纯培养菌液检出限为105CFU/ml,具有良好的敏感性及特异性。染菌样品经在EC增菌液中选择性培养后进行双抗夹心ELISA检测,接种量为0.1～1CFU/g(ml)的样品在培养12h后可检出阳性反应,1～10CFU/g(ml)的样品在培养8h后可检出阳性反应。

应用重组信号蛋白14-3-3间接ELISA诊断日本血吸虫病

目的探讨重组日本血吸虫信号蛋白14-3-3(rSj14-3-3)间接ELISA用于血吸虫病免疫诊断的价值。方法表达并利用纯化的rSj14-3-3与成虫抗原(SjAWA)间接ELISA法分别检测51份急性和49份慢性日本血吸虫病患者和50份正常人血清,以上血清标本同时用SEA致敏的间接血凝试验(SEA-IHA)检测。再以3种方法检测30份华支睾吸虫感染者、24份卫氏并殖吸虫感染者和31份钩虫感染者血清,分析其交叉反应性。结果51份急性和49份慢性血吸虫病患者血清的rSj14-3-3抗体阳性率分别为98.0%和91.8%;SjAWA的检出率分别为96.1%和90.0%;IHA的阳性率分别为98.0%和93.9%。经统计学分析,以上结果无显著性差异(P>0.05)。Sj14-3-3间接ELISA、SjAWA间接ELISA和SEA-IHA对于30份华支睾吸虫感染者的交叉反应性分别为13.3%、20.0%和16.7%,24份卫氏并殖吸虫感染者分别为8.3%、12.5%和12.5%,31份钩虫感染者分别为12.9%、16.1%和12.9%。经统计学分析结果也无显著性差异(P>0.05)。结论rSj14-3-3抗原间接ELISA法诊断日本血吸虫病,具有高度的敏感性和特异性,可用于血吸虫病的免疫诊断。

SPA-ELISA检测棕果蝠血清冠状病毒抗体的研究

目的建立一种敏感、简便的检测蝙蝠血清冠状病毒抗体的方法。方法利用葡萄球菌A蛋白(SPA)能够与某些哺乳动物IgG抗体Fc段非特异性结合的特点,对市售人冠状病毒抗体ELISA试剂盒进行改造,建立SPA-ELISA法,使其适用于蝙蝠血清冠状病毒抗体的检测,并对采集到的55份棕果蝠血清冠状病毒抗体进行检测。结果用SPA-ELISA方法对人冠状病毒试剂盒中阳性与阴性对照、SARS病人恢复期血清、空白对照的检测都得到理想的结果,并从55份棕果蝠血清中检测出2例阳性,阳性率为3.64%(2/55),中和试验进一步证实了结果的真实性。结论所建立的方式适用于检测棕果蝠血清冠状病毒抗体。

A MONOCLONAL ANTIBODY RECOGNIZING NON DERIVATIVE 13 HYDROXY GIBBERELLINS AND THEIR GLUCOSIDES *

The production and characterization of a monoclonal antibody (MAb AB10) against GA 3 glucoside as well as GA 3 is described. MAb AB10 was derived from an immunogen in which human serum albumin (HSA) was linked to GA 3 at carbon 3. This antibody showed high affinity for GA 3 glucoside as well as for 13 hydroxy gibberellins (GA 1, GA 3, GA 5, etc). The affinity of MAb AB10 for 13 hydroxy GAs was significantly reduced by methylation of the 7 oic acid but not by glycosylation of 3 hydroxyl group. Based on this antibody, both of competitive enzyme linked immunosorbent assays (ELISAs) for GA 3 glucoside and for GA 3 were developed. These two ELISAs displayed linear detection ranges from 0 2 pmol to 20 pmol. Using these assays, the fluctuation of GA 3 like and GA 3 glucoside like substances in the leaves of Rumex japonicus was investigated. The results indicated that the glycosylation of free GAs was connected with leaf senescence and that the function of 6 benzyl amino purine in retarding the leaf senescence was probably related to delaying the process of glycosylation of free GAs.