单克隆抗体斑点试验检测血吸虫卵抗原

靶抗原为血吸虫卵糖蛋白的单克隆抗体SM21-3标记过氧化物酶后,用于直接法斑点试验检测血清中虫卵抗原。12份感染兔血清全部呈阳性反应;12份正常兔血清呈阴性反应。8份感染 10 0条及8份感染10条尾蚴的治疗前兔血清呈阳性反应;治疗后1月,血清抗原水平有不同程度下降;治疗后3月,部分血清转为阴性,其余几份均呈弱阳性反应。检测血吸虫病人血清80份,阳性66份,阳性率为82.5％;检测正常人血清60份,未见阳性反应。上述结果表明本方法具有较好的敏感性与特异性,而且方法简单易行,肉眼观察结果,适于现场应用。     

幽门螺杆菌尿素酶抗原的分离和纯化

本研究采用层析技术，以ＳｅｐｈａｄｅｘＧ２００分离幽门螺杆菌尿素酶，从幽门螺杆菌超声破碎物离心上清中一次提纯了尿素酶抗原，产物接近电泳纯并保持了良好的抗原性。我们对５５份抗幽门螺杆菌抗体阴性村本和５０分阳性标本检测发现，符合率达１００％，假阴性和假阳性均为零；大样本临床标本检测也取得了很好的结果。     

双抗原夹心法检测抗HIV-1/2总抗体方法的建立和评价

目的 进一步提高HIv感染诊断试剂的敏感性。方法 以人工合成的HIv—1 gp41．1(sP1)、gp41．2(sP2)、gp120(sP3)、P24(sP4)和HIV—2gp36(sP5)5条多肽，采用双抗原夹心酶链免疫吸附试验(ELISA)原理，以sP1、sP3、sP4和sP5混合包被酶标板作为因相抗原，辣根过氧化物酶标记sp1、sp2、sP4和sP5多肽为标记物，建立了检测抗HIV—1／2总抗体的双抗原夹心ELISA法。结果 检测卫生部药品生物制品检定所第2代40份质控参比血清，其特异性和灵敏度均为100％，高于间接ELISA法(特异性为90％，灵敏度为65％)。检测210份其他病种患者血清均为阴性，与雅培HIVAB试剂比较检测如份健康献血员血清和88份HIv感染者血清，符合率为100％。结论 本方法特异性强、敏感性高，操作简便，适用于献血员的筛选和临床HIv感染的检测。     

合成肽抗原抗人免疫缺陷病毒1／2型抗体酶联试剂盒…

根据人免疫缺陷病毒的基因结构和氨基酸序列，采用因相法合成了ＨＩＶ－１ｇｐ４１、ｂｐ１２０、ｐ２４和ＨＩＶ－２ｇｐ３６的４条多肽，混合包被酶标板做为固相抗原，采用间接酶联免疫吸附试验，建立了检测抗－ＨＩＶ－１／２ＩｇＧ抗体的酶联诊断试剂盒。检测卫生部药品和生物制品检定所提供的４１份质控参比血清，其特异性、敏感性均为１００％，变异系数小于１０％。检测１８６份其它病种病人血清均为阴性，与华怡、巴斯德、金     

抗心磷脂抗体检测及其影响因素的研究

目的：研究血清样品稀释度、温度、离子强度以及样品检测间隔时间对血清抗心磷脂抗体（ＡＣＡ）检测结果的影响。方法：采用酶联免疫吸附测定法（ＥＬＩＳＡ）检测ＡＣＡ。结果：血清样品最佳稀释度为１：５０;３７℃时光吸收值比２２℃和２５℃的光吸收值显著下降;１５ｍｏｌ／Ｌ ＮａＣｌ可明显抑制ＡＣＡ与抗原结合（Ｐ〈０．０１）,抑制率平均为４５．４％,包被１４ｄ以上的检测结果明显高于１ｄ和７ｄ的测定结果（Ｐ〈０．     

乙肝病毒前S1抗原时间分辨荧光免疫分析试剂盒的研制

目的利用时间分辨荧光免疫分析（TRFIA）技术建立乙型肝炎病毒前S1抗原的检测试剂盒。方法应用双抗体夹心法建立乙肝preS1抗原TRFIA检测试剂盒,对试剂盒的各项性能指标进行评估。结果对280份血清样本进行检测并与国产酶联免疫法试剂盒对比,结果显示自制试剂盒的特异性更好：200份正常人血清样本检测结果表明,该试剂盒的cutoff值=阴性对照荧光值×4．5。用自制质控品检测分析内和分析间的精密度分别为3．4％～7．8％,6．9％-8.4％;检测HBsAg及HBeAg无交叉反应。结论试剂盒各项指标均达到临床检测要求,TRFIA法精密度和特异性有较大提高,可替代酶免法试剂盒。     

合成肽抗原抗人免疫缺陷病毒1/2型抗体酶联试剂盒的研制

根据人免疫缺陷病毒（ＨＩＶ）的基因结构和氨基酸序列，采用固相法合成了ＨＩＶ－１ｇｐ４１（ＳＰ１）、ｇｐ１２０（ＳＰ２）、ｐ２４（ＳＰ３）和ＨＩＶ－２ｇｐ３６（ＳＰ４）的４条多肽，混合包被酶标板做为固相抗原，采用间接酶联免疫吸附试验（ＥＬＩＳＡ），建立了检测抗－ＨＩＶ－１／２ＩｇＧ抗体的酶联诊断试剂盒。检测卫生部药品和生物制品检定所提供的４１份质控参比血清，其特异性、敏感性均为１００％，变异系数小于１０％。检测１８６份其它病种病人血清均为阴性，与华怡、巴斯德、金豪等公司的ＨＩＶ诊断试剂比较检测了９０份ＨＩＶ感染者和１４０份正常人血清，除与华怡试剂的阴、阳性及总符合率分别为９９２９％（１３９／１４０）、９８９０％（９０／９１）和９９５７％（２２９／２３０）外，其余均为１００％。３７℃放置４天后试剂的检测结果不受影响。     

广州管圆线虫成虫尿素溶解性抗原分析及其诊断价值的探讨

目的分析广州管圆线虫成虫尿素溶解性抗原,探讨其诊断价值。方法广州管圆线虫成虫匀浆后沉渣经尿素溶解,与成虫水溶解性抗原同时进行SDS-PAGE和Western-blot,分析蛋白谱与抗原谱;用ELISA检测不同样本中相应抗体。结果SDS-PAGE结果显示尿素抗原蛋白条带少于水溶解性抗原;尿素抗原与感染大鼠血清、免疫兔血清和广州管圆线虫病患者血清在32000Mr处均出现强反应带,尿素抗原的反应带条数较水溶性抗原少。两种抗原包被ELISA检测广州管圆线虫病疑似病人血清和感染大鼠血清的阳性率相同;尿素抗原用于检测血吸虫感染小鼠血清的交叉阳性率明显低于水溶性抗原,检测正常大鼠血清、献血员血清及其他非广州管圆线虫感染血清时,假阳性数较水溶性抗原少。结论广州管圆线虫成虫尿素抗原含有32000Mr抗原;广州管圆线虫尿素抗原用于诊断时,与水溶性抗原有同样的敏感性,而特异性高于水溶解性抗原。     

单克隆抗体AU_（14－1）测定人血清宫颈癌抗原

本研究应用抗小鼠宫颈癌单克隆抗体ＡＵ_１４－１所建立的夹心ＥＬＩＳＡ法，测定了人血清宫颈癌抗原．以４０例正常妇女血清的Ａ４９０均值加３个标准差之和（０．２０Ａ４９０Ｕ）作为阳性阈值，对２５例宫颈癌、５２例宫颈炎和１２例其他妇科疾患病人血清进行检测，结果宫颈癌为２５／２５阳性，宫颈炎２／５２阳性（其中１例阳性者为重度宫颈糜烂），其他妇科疾患均为阴性．此外，１例卵巢癌腹水亦为阴性．经统计学分析，ＡＵ１４－１确定的宫颈癌抗原存在于宫颈鳞癌和腺癌病人血清中，其阳性率均为１００％，敏感性１００％，特异性９６．２％．与目前研究的宫颈癌血清标志物ＳＣＣ和ＣＡ—１２５比较，ＡＵ１４－１—ＥＬＩＳＡ对人血清官颈癌抗原的检测，具有较高的敏感性和特异性以及较好的临床应用前景，并进一步证明了肿瘤“进化抗原”的理论．     

弓形虫IgM抗体检测方法的研究

本文以鼠抗人μ链单克隆抗体捕获被测人血清中ＩｇＭ抗体，再以辣根过氧化物酶标记的弓形虫抗原进行直接酶联免疫吸附试验，检测人血清中特异性抗弓形虫ＩｇＭ抗体，并以阻断试验证实该方法的特异性。与风疹病毒ＩｇＭ抗体阳性血清，巨细胞病毒ＩｇＭ抗体阳性血清和类风湿因子等无交叉反应。与进口试剂盒以酶联免疫吸附试验双夹心法（ＤＳ－ＥＬＩＳＡ－Ｔｏｘ－ＩｇＭ）进行比较检测了临床血清样品１０５３份，两者阳性符合率为９５．５６％，ＤＳ－ＥＬＩＳＡ阴性血清在Ｄ－ＥＬＩＳＡ法亦阴性，而且后者灵敏度略高。酶标记抗原和包被抗体的酶标板在４℃中保存６个月仍稳定。试剂盒操作简便，快速，适用于弓形虫病的早期诊断。     

Evaluation of an enzyme-linked immunosorbent assay based on crude leishmania histone proteins for serodiagnosis of human infantile visceral leishmaniasis

Human visceral leishmaniasis (VL) is routinely diagnosed by detecting IgG that specifically binds to Leishmania antigens. The enzyme-linked immunosorbent assay (ELISA) remains a widely used method. However, the biggest challenge remains the choice of antigen with the highest specificity and sensitivity. This study is aimed at assessing the diagnostic performances of crude Leishmania histone (CLH) protein-based ELISAs in Mediterranean VL patients. The CLH proteins were biochemically purified from promastigote nuclear extracts. Their reactivities were analyzed by Western blotting (WB) using rabbit polyclonal antibodies against Leishmania recombinant histones and sera from VL patients, respectively. Then, the diagnostic potential of CLH proteins was validated by the CLH-based ELISA using 42 infantile VL patients' sera and 70 control subjects. The CLH-based ELISA performance was compared to that of the soluble Leishmania antigen (SLA)- and the recombinant K39 (rK39)-based ELISAs. Analysis of the WB profile with the use of polyclonal antibodies confirmed the histone origin of low molecular mass proteins (12 to 16 kDa). All VL samples tested presented antibodies reacting against different antigen fractions; however, recognition patterns were different depending on the reactivity of each serum. CLH-based ELISA showed an excellent ability to discriminate between VL cases and healthy controls (97.6% sensitivity and 100% specificity). It had a diagnostic performance similar to that of rK39-based ELISA (97.6% sensitivity and 97.1% specificity, P = 0.5) and a better serodiagnosis accuracy than the SLA-based ELISA (85.7% sensitivity and 90% specificity, P < 0.05). Therefore, crude Leishmania histone extract could be a valuable antigen for clinical use.     

Serological speciation of human schistosome infections by ELISA with a panel of three antigens

AIMS: To find out whether serology can reliably speciate human schistosomiasis using a simple enzyme linked immunosorbent assay (ELISA) technique. METHODS: Stored sera from 66 patients with microscopically confirmed schistosomiasis were subjected to ELISA using a panel of three antigens, namely: unfractionated Schistosoma mansoni soluble egg antigen (SEA); CEF6, a cationic fraction of SEA; and crude S margrebowiei egg antigen, prepared from an animal schistosome closely related to S haematobium. RESULTS: The optical densities (ODs) obtained using CEF6 as antigen were significantly higher in sera from S mansoni infected patients than in sera from S haematobium infected patients (median OD, 0.810 v 0.595). Using S margrebowiei egg antigen, the optical densities were significantly higher in S haematobium sera than in S mansoni sera (median OD, 0.794 v 0.544). There was no significant difference in optical densities between S mansoni and S haematobium sera using SEA (median OD, 0.725 v 0.737). The ratio of ODs (CEF6 to S margrebowiei egg antigen) was calculated: a ratio of >1 indicated S mansoni infection (sensitivity, 88%) and a ratio of <1 indicated S haematobium infection (sensitivity, 84%). The odds ratio for S haematobium having an OD ratio of <1 was 36.8 (95% confidence interval, 7.0 to 194). CONCLUSIONS: The identity of the infecting species of schistosome can be determined using the panel of antigens described. SEA should be used to screen serum samples, and the CEF6 : S margrebowiei egg antigen ELISA optical density ratio can be used where serological speciation is required.     

Detection of anti-dsDNA by ELISA using different sources of antigens

AIM: To compare different sources of DNA for use in ELISA-based assays for anti-dsDNA antibody detection in systemic lupus erythematosus (SLE) diagnosis. METHOD: Bacterial genomic DNA from Flavobacterium menignosepticum, Proteus vulgalis, Seratia marcescens, Streptococcus pyogenes and Salmonella typhimurium and genomic DNA from human blood were used as antigens for IgG anti-dsDNA detection by enzyme-linked immunosorbent assay (ELISA). Eighty-six sera were tested, 28 derived from patients with SLE, 28 from patients with other rheumatic diseases and 30 from normal human subjects. RESULTS: Genomic DNA from Flavobacterium menignosepticum and human blood had high sensitivity (75%, 82%) and specificity (91%, 91%) for anti-dsDNA detection in diagnosis of SLE. However, human genomic DNA was the most effective antigen of all antigens studied. The assay had a higher sensitivity but lower specificity than commercial ELISA (61% sensitivity and 95% specificity). There was a high level of correlation between commercial ELISA and ELISA using human genomic DNA as antigen (r=0.776, p<0.001) and they exhibited a high level of diagnostic agreement with each other (kappa=0.890, p<0.001). CONCLUSION: The genomic DNA from human blood is a potentially useful source of antigen for the detection of anti-dsDNA by ELISA. However, further studies are required to compare the performance of ELISA using this source of antigen against commercial radioimmunoassays for anti-dsDNA detection.     

Identification of specific antigens of Pseudomonas pseudomallei and evaluation of their efficacies for diagnosis of melioidosis.

Current methods for the diagnosis of melioidosis are based on bacteriological culture. A number of serological tests currently available lack specificity and sensitivity. This is largely due to the use of crude antigens which results in a significant cross-reactivity with sera from individuals infected with other bacteria. In this study five different antigens were prepared and evaluated for their potential usefulness in diagnosis of melioidosis. These included a 19.5-kDa antigen which was previously shown to be specific by Western blotting (immunoblotting), a crude cell extract, a veronal extract, a 39.0-kDa antigen, and an immunoaffinity-purified antigen. All antigens were used for detecting antibody in sera from patients with septicemic melioidosis by indirect enzyme-linked immunosorbent assay. The results were compared with those obtained with sera from patients with other bacterial infections and normal sera from areas where the infection is and is not endemic. The 19.5-kDa antigen exhibited the most satisfactory results, with 92% sensitivity, 91% specificity, 81% positive predictive value, and 96% negative predictive value based on a background obtained with normal sera from the area where the infection is nonendemic. These values were 82% sensitivity, 96% specificity, 94% positive predictive value, and 87% negative predictive value based on results with normal sera from the area where the infection is endemic. Results from this study showed that the 19.5-kDa antigen was potentially useful in the diagnosis of melioidosis and deserves further investigation.     

Serodiagnosis of Helicobacter pylori infection in childhood.

Sera from 100 children (ages, 6 to 16 years) presenting with upper gastrointestinal symptoms were examined for antibodies to Helicobacter pylori by enzyme-linked immunosorbent assay (ELISA) based on crude, loosely cell-associated antigens and a partially purified urease antigen preparation. All children underwent endoscopy, and 20 children were shown to have H. pylori infection by histology or direct culture. Serum anti-H. pylori immunoglobulin G (IgG) levels (crude antigen) were clearly raised in the infected group, particularly after preabsorption of sera against a Campylobacter jejuni antigen preparation, while IgM and IgA ELISA determinations did not discriminate between infected and H. pylori-negative patients. Only 14 children in the infected group had raised anti-urease IgG levels. Two patients in whom the organism was not demonstrated or cultured had raised specific IgG levels against both crude and urease antigens and pathological features consistent with H. pylori disease. Immunoblotting studies did not reveal any single protein antigen or simple combination of antigens that could be considered as a candidate for a more defined serodiagnostic reagent. Anti-H. pylori antibody determinations (crude antigen) performed on posttreatment samples from children in whom the organism could no longer be demonstrated suggested that sustained IgG levels may not be a reliable index of treatment failure. An IgG ELISA based on crude, loosely cell-associated antigens of H. pylori can be used for the serodiagnosis of H. pylori infection in childhood.     

A set of recombinant antigens from Echinococcus granulosus with potential for use in the immunodiagnosis of human cystic hydatid disease

Several recombinant clones expressing antigens from Echinococcus granulosus were isolated previously from a parasite cDNA library using cystic hydatid disease (CHD) patients' sera or rabbit hyperimmune antiserum against a lipoproteic fraction from bovine cyst fluid. Six of these antigens were expressed in Escherichia coli and the purified recombinant proteins were tested in enzyme-linked immunosorbent assay (ELISA) for specific IgG with a panel of sera from patients with surgically confirmed (n = 58) or immunologically diagnosed (n = 71) CHD. Sera from clinically normal individuals (n = 203) and sera from individuals with other helminthic infections (n = 65) were assayed for the assessment of specificity. A cut-off value was determined by receiver-operating-characteristic plots for each antigen. A recombinant antigen B subunit (AgB8/2) presented the highest sensitivity (93.1%), considering the group of sera from patients with CHD surgically confirmed, and specificity (99.5%) and is proposed as the basis for an immunodiagnostic test. The other recombinant antigens tested presented sensitivities between 58.6% and 89.7%, and three of them were considered of complementary value. In subclass-specific ELISA, different IgG isotypes showed dominance in the response for each of the recombinant antigens. There was a clear predominance of IgG4 response for all antigens tested, indicating that this would be the subclass of choice to be assessed for these recombinant proteins.     

Combination of native and recombinant cytomegalovirus antigens in a new ELISA for detection of CMV-specific antibodies

BACKGROUND: Serological detection of cytomegalovirus (CMV)-specific antibodies varies greatly due to antigen composition and the lack of antigen standardization. OBJECTIVES: To develop and evaluate a new ELISA with native and/or recombinant cytomegalovirus antigens for the detection of anti-CMV IgG and IgM antibodies. RESULTS: The diagnostic performance of three anti-CMV ELISAs coated with different CMV antigen preparations, (i) native CMV antigen, (ii) a mixture of recombinant CMV peptides pp150, pp28, gB2 and pp52 and (iii) a combination of native CMV antigens and recombinant CMV IE1 antigen applied in the new Genzyme Virotech CMV ELISA, were compared. All tested sera were derived from patients or healthy blood donors and were predefined with the Dade Behring Enzygnost((R)) CMV ELISA as well as by CMV PCR analysis. Additionally, official well-characterized serum panels were also tested. The new Genzyme Virotech CMV ELISA IgG/IgM test applying a combination of native antigens and recombinant IE1 antigen was evaluated and the performance was compared to the Dade Behring Enzygnost((R)) CMV ELISA. The sensitivities were 98.9% (IgG) and 98.2% (IgM), the specificities were 98.8% (IgG) and 98.9% (IgM) for the Genzyme Virotech CMV ELISA. Furthermore all sera of the BBI mixed titer performance panel as well as the BBI seroconversion panel were identified 100% correctly with the new Genzyme Virotech ELISA. CONCLUSIONS: These data suggest that the new Genzyme Virotech CMV ELISA has higher sensitivity and specificity than ELISAs based on native antigens or recombinant peptides only. Specific combinations of native and recombinant antigens increase the serological detection of CMV infections and may add to further standardization of CMV serology.     

Development of a Highly Specific IgM Enzyme-Linked Immunosorbent Assay for Bartonella henselae Using Refined N-Lauroyl-Sarcosine-Insoluble Proteins for Serodiagnosis of Cat Scratch Disease

The conventional anti-Bartonella henselae IgM enzyme-linked immunosorbent assay (IgM-ELISA) methods for diagnosing cat scratch disease (CSD) remain poor in both sensitivity and specificity. We sought to develop an IgM-ELISA with improved accuracy in the serodiagnosis of CSD by exploring the antigens that are most suitable for an ELISA. We prepared 5 different protein antigens: antigen I (sonicated B. henselae whole-cell antigen), antigen II (N-lauroyl-sarcosine-insoluble antigen), antigen III (processed sarcosine-soluble antigen), and antigen IV and antigen V (sarcosine-insoluble and sarcosine-soluble antigens refined by DEAE-Sepharose Fast Flow ion-exchange chromatography). The IgM antibodies in the sera of 47 patients with clinically suspected CSD (24 definite, 23 suspected) and of 85 healthy individuals were examined by ELISAs using the 5 antigens, and the results were compared with those of an IgM indirect fluorescent antibody assay (IgM-IFA). In a reference panel, which consisted of 5 positive and 5 negative sera, antigen I and antigen III failed to distinguish between the two statuses, whereas the other three antigens succeeded in distinguishing between them. When the cutoff value was set at the 98th percentile of the ELISA index for healthy individuals, the sensitivity of IgM-IFA for the 24 cases of definite CSD was 54%, whereas the sensitivities of the IgM-ELISAs with antigen II, IV, and V were 75%, 83%, and 75%, respectively. The sensitivities of these three IgM-ELISAs for all 47 of the clinically suspected cases were 49%, 64%, and 51%, respectively. In contrast, the sensitivity of IgM-IFA was 28%. These results indicate that the refined sarcosine-insoluble proteins (antigen IV), which possessed the highest specificity among the 5 antigens, are the most appropriate for developing an IgM-ELISA for the highly specific serodiagnosis of CSD.     

Diagnosis of visceral leishmaniasis by enzyme-linked immunosorbent assay using urine samples

A diagnostic method has been developed to detect anti-Leishmania donovani immunoglobulin G (IgG) in urine by enzyme-linked immunosorbent assay (ELISA). In measuring anti-L. donovani IgG, IgA, and IgM in urine, the method performed best in the detection of IgG. The sensitivity and specificity of the assay were determined with panels of urine samples from 62 visceral leishmaniasis (VL) patients, 59 healthy controls from areas of endemicity, 53 healthy controls from areas of nonendemicity, 59 malaria patients, 13 tuberculosis patients, 23 cutaneous leishmaniasis patients, and 7 patients with other diseases. Using L. donovani promastigote crude antigen, the test had 93.5% sensitivity (58 positives of 62 VL patient samples) and 89.3% specificity (191 negatives of 214 non-VL patient samples). The ELISA with acetone-treated L. donovani promastigote antigen raised the sensitivity and specificity to 95.0 and 95.3%, respectively. Western blot analysis revealed that most of the samples that cross-reacted with crude antigen in ELISA did not recognize any antigenic component of L. donovani crude antigen. We also checked 40 serum samples from the same group of VL patients for anti-L. donovani IgG and got 90.0% sensitivity with both crude and acetone-treated antigens. As collection of urine is much easier than collection of serum, the detection of anti-L. donovani IgG in urine with acetone-treated antigen will be useful in epidemiological studies. It could be an adjunct of laboratory diagnosis.     

Immunoenzymatic dot-blot test for the diagnosis of enteric fever caused by Salmonella typhi in an endemic area

Objective: To develop a quick, solid-phase immunoenzymatic test, dot blot, to diagnose typhoid fever by the detection of IgG and IgM antibodies against three Salmonella typh antigens (lipopolysaccharide, crude and flagellar) and to compare the dot-blot test with an enzyme-linked immunosorbent assay (ELISA) using the same antigens and with the Widal agglutination test.
Methods: Blood culture was used as the definitive test. All tests were used for the study of the sera from three groups of individuals: 33 patients suffering typhoid fever, diagnosed by isolation of S. typhi in blood culture; 35 patients with other enterobacterial infections documented by culture; and 156 asymptomatic volunteers, all residents of the same endemic region (Urabá, Colombia).
Results: The best diagnostic efficiency was obtained by detecting IgG against a flagellar antigen dot blot, giving a sensitivity and specificity of 88%. Widal and ELISA tests showed lower diagnostic efficiencies.
Conclusions: The dot-blot test may be useful to diagnose typhoid fever in rural areas lacking technological resources with which to carry out blood cultures or ELlSA tests. The visual reading makes this test practical and cheap for these regions.