Anti-dextran antibodies of carp detected by the enzyme-linked immunosorbent assay (ELISA)

Carp produce anti-alpha (1-6) dextran antibodies after immunization with a vaccine of Leuconostoc mesenteroides B512. These antibodies can be determined by passive haemagglutination, quantitative precipitation or by ELISA. In our hands the ELISA has proved to be 100 times more sensitive than the passive haemagglutination test. We could not found any correlation between the anti-dextran activity estimated with the passive haemagglutination on the one and the ELISA on the other hand.     

The detection of antibodies to mycobacterium tuberculosis by microplate enzyme-linked immunosorbent assay (ELISA)

The detection of antibodies to Mycobacterium tuberculosis by enzyme-linked immunosorbent assay has proved to be a potentially useful technique for the serodiagnosis of tuberculosis. The technique is capable of full automation. The use of a purified antigen should further improve the sensitivity of the method.     

Detection of circulating antibodies in cutaneous leishmaniasis by enzyme-linked immunosorbent assay (ELISA)

An immunoenzymatic diagnostic technique applicable to cutaneous leishmaniasis is described. The antigen used (Leishmania tropica major) was equally useful in diagnosing visceral and mucocutaneous forms of the disease. The criteria for positivity were defined by using groups of negative controls, and the specificity of the reaction was evaluated by using sera from patients with various diseases. Among these, sera from patients with lepromatous leprosy, tuberculosis, or African trypanosomiasis strongly cross-reacted with leishmania antigen. Examining serial dilutions of the sera facilitated the interpretation of the results and eliminated a significant percentage of false positives.     

Use of the enzyme-linked immunosorbent assay (ELISA) for detection of circulating antibodies to human leishmaniasis

In an attempt to lay the background work of immunodiagnosis of human leishmaniasis in Taiwan, the usefulness of enzyme-linked immunosorbent assay (ELISA) for detection serum antibodies in large regional groups was studied. Antigens were prepared from promastigotes of Leishmania tropica major recently isolated in our laboratory by Chao. One hundred and sixty-five serum samples were collected from medical students of National Yang-Ming Medical College (YM), Taipei, 61 from residents of San-hsing District (SH), I-lan County, 9 from residents of Wu-lai District (WL), Taipei County, 2 from patients with cutaneous leishmaniasis, 6 from laboratory workers in the Department of Parasitology (LW), National Yang-Ming Medical College, and 1 from a patient with the history of hypersensitive to mosquito bites. The result of the ELISA were analyzed statically. YM students had the lowest serum antibody levels to this parasite. The laboratory workers and the SH residents had a significantly higher antibody prevalence rate than the YM students, but a significantly lower rate than positive patients. Positive/pseudopositive rate in non-patient groups was 0.82%. Tracing of these two suspected cases are in progress. The regional high antibody levels in the SH residents suggest that a risk of human leishmaniasis may be significant in the population tested. Using our antigen preparations we demonstrated that the ELISA is sensitive, rapid, and easy to perform and is therefore useful in screening and detecting of circulating anti-leishmania antibodies in serosurvey of large sample size.     

Antibodies to coccidia: detection by the enzyme-linked immunosorbent assay (ELISA)

Summary The ELISA test was used for the detection of antibodies to coccidia in the serum and/or egg yolk of chickens infected with Eimeria acervulina, E. maxima or E. tenella and in the serum of rats infected with E. nieschulzi. Antigens prepared from different developmental stages of the parasite were tested and the cross-reaction between different species of Eimeria were examined. The variability in cross-reactivity of different species and the advantages and possible applications of the test are discussed.     

Detection of antibodies to Epstein-Barr virus antigens by enzyme-linked immunosorbent assay

An enzyme-linked immunosorbent assay (ELISA) is described for the serologic analysis of antibodies to Epstein-Barr virus (EBV)-associated nuclear antigen (EBNA), viral capsid antigen (VCA), and early antigen (EA). The specificity of each of the ELISAs was demonstrated by the use of well-characterized human sera shown by immunofluorescence assay to be variously reactive for antibodies to one or more of the three viral antigens studied. The ELISA for EBNA was four to 256 times more sensitive than immunofluorescence assays with all 33 EBNA-positive sera tested. The ELISAs for VCA and EA were also more sensitive than immunofluorescence assays: approximately 50% of the sera tested showed higher antibody titers. Sera that were negative for all three antigens by immunofluorescence assay were also negative by ELISA for each antigen. These ELISAs for EBV are rapid, sensitive, and objective and thus provide new and valuable methods for the detection of antibodies to EBV-related antigens.     

ELISA双抗原夹心法检测内脏利什曼病抗体的研究

目的观察rK39抗原酶联免疫吸附试验双抗原夹心法(ELISA夹心法)检测内脏利什曼病抗体用于内脏利什曼病诊断与宿主动物感染调查的可行性。方法采用ELISA夹心法与rK39免疫层析试条法(ICT)同步检测内脏利什曼病抗体。结果 5种家畜血清229份,7种鼠类标本238份,ELISA夹心法和rK39 ICT法抗体检测均阴性;接种利什曼原虫灰仓鼠、草原兔尾鼠标本33份,13份阳性,阳性率39.4%;塔里木兔标本119份,阳性7份,阳性率5.9%;非疫区儿童血清29份,全部阴性;疫区无内脏利什曼病症状人血清250份,4份两种方法均阳性,阳性率均为1.6%;住院内脏利什曼病病人血清67份,两种方法的阳性率分别为68.7%和67.2%。共检测人和其他动物标本965份,两种方法的阳性符合率98.6%,阴性符合率99.9%。ICT相同显色等级的阳性标本,ELISA跨10个滴度。结论 ELISA夹心法可检测多种动物内脏利什曼病抗体,抗体滴度具有定量意义。该方法适用于内脏利什曼病诊断、疗效观察和流行病学调查。     

A new solid-phase enzyme-linked immunosorbent assay for specific antibodies to measles virus

A convenient and flexible enzyme-linked immunosorbent assay system for the detection of specific antibodies to measles virus has been developed. In this system infected cells are desiccated on 96-well microtiter plates and stored at room temperature. After incubation of samples to be tested in the cell-coated plates and subsequent washing, bound antibodies are detected with a peroxidase-conjugated staphylococcal protein A probe. After another washing and the addition of the appropriate substrate, the amount of bound probe is estimated by colorimetric analysis. This technique offers several advantages. The need for a purified viral antigen source is obviated. The plates are easily prepared and can be stored for months at room temperature. Major viral epitopes, including surface glycoproteins as well as cytoplasmic viral antigens, are preserved despite desiccation. The method is more sensitive than the conventional means of virus-specific antibody detection.     

The enzyme-linked immunosorbent assay (ELISA) for the immunodiagnosis of schistosomiasis.

The enzyme-linked immunosorbent assay (ELISA) done with soluble egg antigens (SEA) of Schistosoma mansoni was utilized for the detection of infections with schistosomes. The method readily detected experimental infections in NIH outbred, New Zealand black, and New Zealand white mice by 6-10 weeks post-exposure to S. mansoni cercariae. In addition, the test was negative when the sera from 11 Puerto Rican normal controls were examined and was positive in 8 of 10 serum samples from humans with schistosomiasis mansoni. However, extensive cross-reactivity was seen when using serum from humans with fascioliasis, trichinosis, cysticercosis, and echinococcosis. Thus the ELISA test done with SEA as antigen lacks immunologic specificity. For the method to be an effective seroepidemiological tool in areas where these parasites are endemic further purification of the antigen and more extensive understanding of its components are needed.     

Micro enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of New World leishmaniasis

Of 21 confirmed cases of New World leishmaniasis, 16 exhibited antibody to antigens of the promastigote of Leishmania braziliensis panamensis by the enzyme-linked immunosorbent assay (ELISA). Comparison of antibody titers obtained by ELISA with titers obtained by indirect immunofluorescence using an amastigote substrate confirmed that the sensitivities of the two techniques were within the same range (r = 0.80). Although sera from patients with New World leishmaniasis failed to react with antigens extracted from epimastigotes of Trypanosoma cruzi, sera from 39 cases of Chagas' disease were reactive with promastigotes of L. braziliensis panamensis. This apparent unidirectional cross-reactivity has been attributed to differences in potency of the antigenic stimulus presented in the two diseases.     

An enzyme-linked immunosorbent assay (ELISA) for field diagnosis of visceral leishmaniasis

A simplified enzyme-linked immunosorbent assay (ELISA) was evaluated as a diagnostic test for visceral leishmaniasis in the field on 222 individuals with splenomegaly and 110 controls. The test was shown to have a sensitivity of 98.4% and specificity of 100% when compared with parasite identification by splenic aspiration. The data indicate that the ELISA is an accurate, safe, and economical alternative to splenic aspiration for the diagnosis of visceral leishmaniasis.     

Demonstration of Crohn's disease tissue-specific proteins by enzyme-linked immunosorbent assay (ELISA)

Theories on the etiology of Crohn's disease have included extrinsic agents and intrinsic bowel wall defects. We sought to determine the presence of immunoreactive antigens specific to Crohn's disease tissue by modifying the enzyme-linked immunosorbent assay. Tissue proteins were extracted from four patients with Crohn's disease and from four normal segments of colon from patients with colonic cancer. These tissue extracts were further purified on Con A Sepharose 4B affinity column. The glycoproteins eluted from this column were adsorbed by polystyrene plates as antigen and tested against 85 sera from patients with Crohn's disease, ulcerative colitis, other diarrheal diseases, and normal subjects. Sera from 48 patients with Crohn's disease showed significantly greater recognition of Crohn's disease tissue glycoproteins than sera from 27 disease controls (P less than 0.0125) and 10 normal subjects. These Crohn's disease sera also showed preferential recognition of glycoproteins extracted from Crohn's disease tissue compared to glycoproteins from normal colonic tissue (P less than 0.0005). The nature of these immunoreactive proteins, whether extrinsic or intrinsic, is not yet known. The ELISA may help in further characterization of Crohn's disease tissue-specific glycoprotein(s) and to develop a clinically useful serological test.     

Detection of Cysticercus cellulosae antigens in cerebrospinal fluid by dot enzyme-linked immunosorbent assay (Dot-ELISA) and standard ELISA

The dot enzyme-linked immunoassay and standard enzyme-linked immunoassay were used to detect Cysticercus cellulosae antigens in cerebrospinal fluid of patients suffering with neurocysticercosis. Using the dot enzyme-linked immunoassay, 10 of 17 patients (59%) were positive at a reciprocal titer of 128 (range 128-1,024). In the standard assay, 13 of 17 (77%) were positive (range 128-512). Specificity was 100% in both assays using 48 cerebrospinal fluids from patients with various central nervous system infections. The quantification of antigens in cerebrospinal fluid using standard assay and photometric readings showed a range of 17 to 138 ng/ml. The results indicate that both assays are sensitive, specific, and economical for the diagnosis of neurocysticercosis.     

Diffusion-in-gel enzyme-linked immunosorbent assay, ELISA and IFA test in the detection of malarial antibodies

Malarial antibodies in 80 patients were measured using the diffusion-in-gel enzyme linked immunosorbent assay (DIG-ELISA), enzyme-linked immunosorbent assay (ELISA) and the indirect fluorescent antibody (IFA) test. Good correlations were obtained between all three tests in terms of sensitivity and reliability. DIG-ELISA has the advantage of being a rapid diagnostic tool for the detection of malarial antibodies.