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At least 55 records · Page 3Linked to original sources
PubMed1986

IgM-IFA, IgM-ELISA, DS-IgM-ELISA, IgM-ISAGA, performed on whole serum and IgM fractions, for detection of IgM anti-toxoplasma antibodies during pregnancy.

The traditional IgM-ELISA has a better sensibility and specificity than IgM-IFA when these two tests are performed on whole sera, but in many cases (sera titer values of greater than 200 I.U./ml) the presence of IgM antitoxoplasma antibodies can be detected only after purification of IgM fractions. The separations of IgM fractions avoids either false positive results due to the rheumatoid factors or antinuclear antibodies, and false negative results due to the competition between IgG and IgM antibodies. The present investigation has shown that antibody titers obtained by IgM-IFA and traditional IgM-ELISA correlate well with DS-IgM-ELISA and IgM-ISAGA performed on whole serum. The false negative results that frequently occur with IgM-IFA and traditional IgM-ELISA performed on whole sera having sera titer values of greater than 200 I.U./ml in IgG IFA are avoided when the same sera were tested by DS-IgM-ELISA and IgM-ISAGA. All the sera which gave positive results by DS-IgM-ELISA were also positive when tested with IgM-ISAGA. Our researches demonstrate the high specificity and sensitivity of IgM-ISAGA and DS-IgM-ELISA performed on whole serum.

Antibodies↗
PubMed1987

Comparison of two commercially available anti-HIV ELISAs: Abbott HTLV III EIA and Du Pont HTLV III-ELISA.

Serum specimens were tested for HIV antibodies by two commercially available ELISAs (Abbott HTLV III EIA and Du Pont HTLV III-ELISA). The specificity and sensitivity of these assays were determined by comparison with indirect immunofluorescence and Western blot analysis. Specificity ranged from 94.3% in the Abbott assay to 97.9% in the Du Pont-ELISA. The sensitivity was 100% in the Abbott-ELISA and 99% in the Du Pont test. With both tests, false-positive results occurred predominantly in sera from patients with immunological disorders (kidney transplant recipients, lymphoma, Stevens-Johnson syndrome, etc.), whereas symptomatic AIDS-patients, patients with ARC, and persons with a defined risk for HIV infection could be diagnosed unequivocally. Specificity and sensitivity of anti-HIV ELISAs seemed to depend not only on definition of the cutoff value but also on other factors, such as antigen preparation and inactivation measures. Testing of ELISA-reactive sera by confirmatory tests remains necessary.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Analysis of antibody reactivities in ELISA using protein blots as antigen substrates: S-ELISA.

We describe here a novel immunoassay procedure, designated strip-ELISA (S-ELISA), in which specific antigens are purified by SDS-PAGE, transferred to support membranes, and utilized in situ as substrate in routine ELISA procedures. Using two different lentivirus systems, simian immunodeficiency virus and equine infectious anemia virus, we demonstrate the utility of S-ELISA for screening hybridoma supernatants during production of monoclonal antibodies and for the dissection of polyclonal antibody responses into defined antigen specificities. The data presented here indicates that the S-ELISA combines the sensitivity of conventional ELISA with the specificity afforded by Western blotting procedures, producing a relatively simple and versatile assay for evaluating antibody reactivities.

Animals↗
PubMed1992

Comparison of blocking dot ELISA and competitive ELISA, using a monoclonal antibody for detection of bluetongue virus antibodies in cattle.

A blocking (B) dot enzyme-linked immunosorbent assay (ELISA), using a monoclonal antibody (mAb) against a group specific antigen of bluetongue virus (BTV) is described for the detection of BTV antibodies to BTV in cattle sera. Dots of BTV antigens were adsorbed to nitrocellulose (NC) strips and/or NC mounted in the windows of dipsticks. After blocking the remaining sites of the NC paper with milk powder solution and immersion in the test sample, the NC strips and dipsticks were exposed to mAb. Bound mAb was detected with peroxidase conjugated anti-mouse IgG (H and L). In the absence of anti-BTV antibody in the test sample, BTV antigen sites were reactive with mAb as indicated by a brown colored dot in the presence of the enzyme substrate, hydrogen peroxide and diaminobenzidine. In the presence of sufficient anti-BTV antibodies no color reaction was observed. The performance of these assays in detecting anti-BTV antibody in field blood eluate samples, prepared from whole blood dried on filter paper, from 395 bluetongue-free cattle in Canada and 635 sentinel cattle in Florida, USA, was evaluated and compared with the standard competitive (C) ELISA. The specificity of the dipstick B-dot ELISA was identical to that of the C-ELISA in testing of BT-free Canadian cattle but not in the testing of samples from the sentinel cattle in Florida, resulting in values of 100% diagnostic and 88.9% relative specificity, respectively. Based on the C-ELISA, the specificity of the NC strip B-dot ELISA was low and in the same order as that of the dipstick assay.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2003

One-tube semi-nested PCR-ELISA for the detection of human cytomegalovirus DNA sequences; comparison with hybridization-based and semi-nested-based PCR-ELISA procedures.

Amplification of DNA targets by polymerase chain reaction (PCR) followed by their colorimetric detection in an enzyme-linked immunosorbent assay (ELISA) is increasingly used in both immunological research and clinical practice. Several methods for the labeling and detection of amplified DNA sequences have been previously described. In this study, we compared the conventional hybridization-based PCR-ELISA with a modified semi-nested and one-tube semi-nested PCR-ELISA for the detection of human cytomegalovirus (HCMV) DNA. Amplified DNA sequences were labeled with biotin and 2,4-dinitrophenyl (DNP), and detected by DNP-specific monoclonal antibody conjugated to alkaline phosphatase. Using a cloned HCMV DNA as a template, we found that the one-tube semi-nested PCR-ELISA gave a strong positive response when 20 copies of the template were used, whereas both the hybridization-based and the semi-nested-based PCR-ELISA required at least 200 template copies. The claim of higher sensitivity and robustness of the one-tube semi-nested assay was also supported by the analysis of plasma samples from patients treated for HCMV infection. Since the modified one-tube semi-nested PCR-ELISA is quick, sensitive and easy-to-perform, it can be used with advantage in routine identification of DNA targets in clinical and other specimens.

Cytomegalovirus↗
PubMed1995

Comparative study of ELISA and indirect immunofluorescence for the detection of anti-neutrophil cytoplasmic antibodies. Evaluation of the SCIMEDX/EURO Diagnostica ELISA assay in a clinical setting.

This study evaluates the performance of a commercial ELISA assay for detection of anti-neutrophil cytoplasmic antibodies (ANCA). Anti-proteinase 3 (anti-PR3) and anti-myeloperoxidase (anti-MPO) ELISA by (SCIMEDX/EURO Diagnostica, Denville, NJ) were compared with the indirect immunofluorescence (IIF) method using ethanol-fixed neutrophils. Three hundred sixty serum samples were examined. There was complete correlation of results in 357 (99.2%) cases between cANCA pattern and anti-PR3 results, and in 356 (98.9%) cases between pANCA pattern and anti-MPO ELISA results. The specificity of ELISA for detection of vasculitis was 95.7% and sensitivity was 60%, whereas for IIF, they were 95.7% and 65%, respectively. The ELISA showed good reproducibility with interassay variation (CV), ranging from 7.1% to 13.2%. Our results show that SCIMEDX/EURO Diagnostica ELISA for ANCA is a reliable and reproducible method that is as good as IIF for detection of ANCA.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1986

The relationship between toxocara ELISA absorbance values and toxocara ELISA titres: a comparative study.

Enzyme-linked immunosorbent assays (ELISAs) may be made by a variety of techniques at one or several serum dilutions which is very confusing for clinicians. This study compares the ELISA results from two centres on sera from 12 patients investigated for ocular toxocariasis by two common ELISA methods--the absorbance and titration techniques. With one exception, ELISA results by the two methods correlated well. For reasons outlined, the absorbance ELISA method is likely to remain the preferred method in New Zealand and Australia. Attention is drawn to the implications of the serum response to Toxocara canis larvae, and the need to evaluate ELISA results against clinical findings is emphasized.

Absorption↗
PubMed1996

An indirect double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) using baculovirus-expressed antigen for the detection of antibodies to glycoprotein E of pseudorabies virus and comparison of the method with blocking ELISAs.

Antibodies in porcine sera against glycoprotein E (gE) of pseudorabies virus (PRV) are usually measured in blocking enzyme-linked immunosorbent assays (ELISAs) with one or two murine monoclonal antibodies (MAbs) directed against gE. Our aim was to develop a confirmation assay which is based on another principle and which is able to detect antibodies directed against most potential binding sites on gE with high specificity. Therefore, we developed an indirect double-antibody sandwich assay (IDAS) using recombinant gE expressed by baculovirus (BacgE960). A fragment of the gE gene consisting of nucleotide positions +60 to +1020 of gE, coding for the major antigenic sites of gE but not the transmembrane region, was cloned behind the signal sequence of PRV gG and the p10 promoter in a baculovirus vector. Immunoblot analysis showed that the expressed protein reacted with MAbs directed against five of the six antigenic sites on gE. Although the conformation of some antigenic sites, notably antigenic sites E and C, was not identical to their natural conformation, the expressed protein bound gE-specific antibodies in porcine sera in Western blots (immunoblots) and ELISAs. For the IDAS, a coating MAb directed against the nonimmunodominant antigenic site A on gE was chosen. A major obstacle in binding ELISAs, such as the IDAS, appeared to be the high nonspecific binding activity observed in porcine sera. As a result, sera could be tested only in relatively high dilutions in the BacgE960 IDAS, in contrast to the testing of sera in blocking ELISAs. The sensitivity and specificity of the newly developed BacgE960 IDAS were evaluated and compared with those of five commercially available blocking ELISAs by using several sets of sera of known PRV disease history. The BacgE960 IDAS assay had a high diagnostic specificity and a moderate sensitivity. The five blocking ELISAs differed remarkably in sensitivity and specificity, thereby illustrating the need for standardization and confirmation. We conclude that the BacgE960 IDAS is a useful and specific additional (confirmatory) test for the detection of antibodies to gE.

Animals↗
PubMed1999

Comparison of PanBio dengue duo enzyme-linked immunosorbent assay (ELISA) and MRL dengue fever virus immunoglobulin M capture ELISA for diagnosis of dengue virus infections in Southeast Asia.

The performances of the MRL dengue fever virus immunoglobulin M (IgM) capture enzyme-linked immunosorbent assay (ELISA) and the PanBio Dengue Duo IgM capture and IgG capture ELISA were compared. Eighty sera from patients with dengue virus infections, 24 sera from patients with Japanese encephalitis (JE), and 78 sera from patients with nonflavivirus infections, such as malaria, typhoid, leptospirosis, and scrub typhus, were used. The MRL test showed superior sensitivity for dengue virus infections (94 versus 89%), while the PanBio test showed superior specificity for JE (79 versus 25%) and other infections (100 versus 91%). The PanBio ELISA showed better overall performance, as assessed by the sum of sensitivity and specificity (F value). When dengue virus and nonflavivirus infections were compared, F values of 189 and 185 were obtained for the PanBio and MRL tests, respectively, while when dengue virus infections and JE were compared, F values of 168 and 119 were obtained. The results obtained with individual sera in the PanBio and MRL IgM ELISAs showed good correlation, but this analysis revealed that the cutoff value of the MRL test was set well below that of the PanBio test. Comparing the sensitivity and specificity of the tests at different cutoff values (receiver-operator analysis) revealed that the MRL and PanBio IgM ELISAs performed similarly in distinguishing dengue virus from nonflavivirus infections, although the PanBio IgM ELISA showed significantly better distinction between dengue virus infections and JE. The implications of these findings for the laboratory diagnosis of dengue are discussed.

Adolescent↗
PubMed2001

Immunodiagnosis of human fascioliasis by an enzyme-linked immunosorbent assay (ELISA) and a micro-ELISA.

Enzyme-linked immunosorbent assay (ELISA) and micro-ELISA were evaluated for their ability to detect anti-Fasciola hepatica antibodies in humans by using excretory-secretory antigen. The sensitivity of each method was 100%, but the specificity was 100% for ELISA and 97% for micro-ELISA. The micro-ELISA could be used as a screening assay and ELISA could be used as a confirmatory method for the serodiagnosis of human fascioliasis.

Animals↗
PubMedDate not supplied

Performance indexes of a dot-enzyme-linked immunosorbent assay (dot-ELISA) and an enzyme-linked immunosorbent assay (IgG-ELISA) for field surveys of New World leishmaniasis.

Diagnostic performance indexes of sensitivity, specificity, positive predictive value and efficiency were determined for dot-ELISA and IgG-ELISA tests in 340 leishmaniasis sera. Sensitivity of the dot-ELISA was significantly lower than IgG-ELISA's; the two tests had indexes of specificity and positive predictive value of the same magnitude. Seventy-eight sera gave a negative dot-ELISA test result and a positive IgG-ELISA test result. When sera were classified according to different criteria as how to interpret this diversity, the kappa statistic did not corroborate the classification indicating that the two tests display a substantial strength of agreement. The results presented indicate that performance indexes accrued in a survey where variables are well known may be extrapolated to other population studies if the disease presents itself as highly prevalent (due to a selection bias or not) and may be expected to discriminate a disease status among test positives.

Enzyme-Linked Immunosorbent Assay↗
PubMed2005

Comparative diagnostic potentiality of ELISA and dot-ELISA in prepatent diagnosis of experimental Fasciola gigantica infection in cattle.

A glycoprotein (27 kDa) was isolated from crude somatic antigen of Fasciola gigantica by two steps affinity chromatography and was used in early detection of experimental fasciolosis in cattle by indirect ELISA and in dot-ELISA formats. Although, anti-27 kDa antibodies could be detected after 3 weeks post infection (WPI) by dot - ELISA which was one week later than indirect ELISA. The test, dot-ELISA, was more convenient in field application. By the test (dot-ELISA) the infection could be equally detected in animals infected with 100, 200 and 300 metacercariae of F. gigantica with high sensitivity. Further, the antigen (27 kDa) was not found to react with goat sera infected with Paramphistomum epiclitum, which are giving strong reaction to homologous immature and mature fluke antigens of P. epiclitum.

Animals↗
PubMed1997

Magnetic bead enzyme-linked immunosorbent assay (ELISA) detects antigen-specific binding by phage-displayed scFv antibodies that are not detected with conventional ELISA.

An efficient means for the detection of antigen-specific binding by phage-displayed antibodies would facilitate the selection of such phage, especially from libraries with large repertoires of V-genes. We report the development and characterization of a magnetic bead phage ELISA which detects antigen binding phage which could not be detected by conventional ELISA. We were attempting to select phage binding to the oncodevelopmental antigen, heat-stable alkaline phosphatase (HSAP). Although there was an obvious enrichment in the phage titers after successive rounds of selection, we were unable to detect antigen-binding phage by ELISA on a plastic surface. However, ELISA with a suspension of superparamagnetic particles covalently conjugated to HSAP effectively identified antigen-binding phage after the fourth round of selection. This method could also detect antigen-specific binding of individual phage clones. Some of the phage clones bound to either amino- or carboxy-terminal-conjugated HSAP, perhaps reflecting the differences in the exposed epitopes. It is suggested that a sensitive method such as magnetic bead phage ELISA be tried before declaring a phage selection as unsuccessful or concluding that a phage clone does not bind antigen.

Alkaline Phosphatase↗
PubMed1989

Quantitation of IgG antibody to Streptococcus pneumoniae vaccine by ELISA and FAST-ELISA using tyraminated antigen.

We examined two ELISA methods for measuring antibodies to Streptococcus pneumoniae using tyraminated S. pneumoniae polysaccharide types 3, 7N, 9F and 14 as antigens. The ELISA has the usual format with a relatively long incubation time whereas the FAST-ELISA has a short incubation time and employs a different solid-phase configuration. We showed that both techniques can be used for the detection of antibodies to S. pneumoniae polysaccharides. Although its analytical sensitivity is about 1/10 of that of the ELISA, the FAST-ELISA is sufficiently sensitive to distinguish protective from unprotective levels of antibodies to the types of S. pneumoniae studied. In studying pre- and post-immunization response, we showed that type 3 is the most immunogenic.

Antibodies, Bacterial↗
PubMed1988

Comparison between standard ELISA and dot-ELISA for serodiagnosis of human trichinosis.

The dot enzyme-linked immunosorbent assay (dot-ELISA) provided rapid and accurate detection of human trichinosis. Comparable sensitivity and specificity of the standard ELISA and dot-ELISA were obtained when sera of 18 confirmed cases of trichinosis were screened. Cross-reactivity was assayed with sera from 31 Chinese subjects with other parasitic infections. Only 2 cross-reactions occurred in the dot-ELISA, compared with 7 in the standard ELISA.

Antigens, Helminth↗
PubMedDate not supplied

Comparison of immunoglobulin G enzyme-linked immunosorbent assay (IgG-ELISA) and haemagglutination inhibition (HI) test for the detection of dengue antibodies. Prevalence of dengue IgG-ELISA antibodies in Tahiti.

An immunoglobulin G enzyme-linked immunosorbent assay (IgG-ELISA) for the detection of dengue antibodies is described and compared to the haemagglutination inhibition test (HI). The sensitivity, specificity and agreement rate between the 2 techniques were good. The coefficients of correlation between IgG-ELISA and HI results, using dengue 1-4 antigens, were highly significant (P less than 0.001 for either antigen). IgG-ELISA was rapid, and easy to perform and suitable for large-scale studies. Between April and June 1987, a baseline serosurvey of the prevalence of dengue antibodies in age-stratified samples of children was carried out in Tahiti using IgG-ELISA. 327 children were tested against each dengue serotype. There was no significant difference between sex. Overall rates ranged from 7.4% in children under 5 years to 83.1% in those aged 15-19 years. Dengue 4 being the only serotype involved since 1979, specific responses to dengue 4 were found in higher proportion among children under 8 years old, while the IgG-ELISA responses were more widely reactive among children aged above 8 years (P less than 0.001). The acquisition rate of dengue 4 antibodies was 2.95% on average per year in children under 8 years of age.

Age Factors↗