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At least 19 recordsLinked to original sources
PubMed1988

Comparison of Dot-ELISA, ELISA and IFAT for the detection of IgG antibodies to Sarcocystis muris in experimentally infected and immunized mice.

The dot enzyme-linked immunosorbent assay (Dot-ELISA) was used for the detection of IgG antibodies to Sarcocystis muris and compared with the enzyme-linked immunosorbent assay (ELISA) and the indirect fluorescent antibody test (IFAT). In experimentally infected mice, first positive reactions occurred in the Dot-ELISA between 18 and 32 days after infection (dpi), in the ELISA between 18 and 49 dpi, and in the IFAT between 11 and 25 dpi. Maximum titers were 1:40 960 in the Dot-ELISA, 1:1280 in the ELISA and 1:2560 in the IFAT. High titers persisted until the end of the examination period (182 dpi) in all 3 tests. In immunized mice, all 3 tests detected antibodies 7 days after the first injection of protein antigen. The highest titers of 1:5120 and 1:10 240 were recorded in the Dot-ELISA after 35 days; titers of 1:1280 and 1:2560 were observed in the ELISA, and titers of 1:160 and 1:320 in the IFAT after 42 days. No false-positive reactions occurred in the Dot-ELISA and in the IFAT when 177 sera from non-infected mice were examined, but 1% (2/177) of the sera reacted positively in the ELISA. Sixty-three percent (94/150) of sera from mice infected experimentally with Toxoplasma gondii showed slight positive reactions up to 1:40 in the Dot-ELISA; 9% (13/150) of the sera reacted positively up to 1:40 in the IFAT and 4% (6/150) up to 1:20 in the ELISA. The Dot-ELISA appears to be a good alternative to the ELISA and the IFAT in the serodiagnosis of sarcosporidiosis and should be further evaluated for the serodiagnosis of other parasitic diseases.

Animals↗
PubMed1992

[Comparative study of immunoenzyme tests ELISA-G and ELISA-M, indirect immunofluorescence, and complement fixation in the diagnosis of human cysticercosis].

A comparative study of four immunological tests used for anti-Cysticercus antibodies detection--Enzyme-Linked ImmunoSorbent Assay IgG (ELISA-G) and IgM (ELISA-M), indirect immunofluorescence (RIFI) and complement fixation (RFC)--was made in serum and cerebrospinal fluid (CSF). 539 patients with symptoms suggesting cysticercosis, 450 relatives of these patients and 133 normal people (control group) were examined. 1122 serum samples and 120 CSF samples were analysed by ELISA-G and RIFI, 83 sera and 60 CSF also by RFC, and 28 CSF by ELISA-M. 5.2% serum samples were reagent in ELISA-G and RIFI, and 3.5% of them had discordant results. All control group sera were negative. The same tests in CSF were positive in 16.7% and had discordant results in 7.5%. ELISA-G and RIFI in serum and CSF had concordant results in 89.6% (17.7% were positive). ELISA-G, RIFI and RFC had concordant results in 54.2% sera (16.9% positives) and in 81.7% CSF (11.7% positives). When ELISA-G and RIFI were negative, RFC was positive in 41.0% sera and 11.7% CSF. ELISA-G and ELISA-M had concordant results in 78.6% CSF. When these results were discordant ELISA-G was positive in 10.7% and ELISA-M in another 10.7%. It is necessary to use concomitantly several immunological tests for anti-Cysticercus antibodies detection in serum and in CSF, in attempting to reach correct diagnosis.

Animals↗
PubMed1991

Comparison of sandwich-ELISA and GM1-ELISA for the detection of Escherichia coli thermolabile enterotoxin.

Two different microtiter plate ELISA tests were devised for the detection of Escherichia coli thermolabile toxin (LTh) either free or extracted from isolated colonies. Both tests used as detection systems purified anti-LTh rabbit immunoglobulins conjugated to biotin, streptavidin peroxidase and TMB. The tests differed by their capture phase which was the GM1-ganglioside for GM1-ELISA and purified anti-LTh rabbit immunoglobulins for sandwich ELISA. The two methods were rapid since they could be performed in less than 2 hours. The detection limits for purified LT were 50 pg/ml and 1.3 ng/ml for sandwich ELISA and GM1-ELISA respectively. For the detection of toxinogenic isolates the extraction buffer containing Triton X-100 was always superior to polymyxin buffer. Using the polymyxin extraction buffer the sandwich ELISA was again more sensitive than the GM1-ELISA since a lower number of isolated colonies could be used for the detection of positive strains. With the Triton X-100 buffer both ELISAs could detect positive strains using a single colony but the sandwich ELISA gave the highest delta OD. We concluded that our sandwich ELISA can rapidly detect either the free Escherichia coli thermolabile toxin or LTh producing strains and could be applied routinely.

Cell Line↗
PubMed1992

Evaluation of a recombinant antigen ELISA for the diagnosis of acute toxoplasmosis and comparison with traditional antigen ELISAs.

An evaluation of five ELISA methods for the diagnosis of acute toxoplasmosis was undertaken by comparing a laboratory-produced ELISA employing two recombinant Toxoplasma gondii polypeptides as antigen with a laboratory-produced ELISA and three commercially available ELISAs employing traditional parasite antigen preparations derived from whole tachyzoites. With a panel of 75 sera from patients who showed either serological and clinical evidence of acute toxoplasmosis, or of diseases caused by other infectious agents, or from patients who showed no evidence of infectious disease, the ELISAs gave overall positive predictive values of 81.6-100%, negative predictive values of 87.8-100%, sensitivities of 81.3-100%, and specificities of 83.7-100%. No two ELISAs gave identical results with all sera tested. In total, the ELISA based on the two recombinant T. gondii polypeptides appeared to be the most specific ELISA in this comparison, showing positive predictive values and specificities of 100% for all groups of patients tested. The overall negative predictive value for this ELISA was 87.8% and the sensitivity was 81.3%. Therefore, the ELISA based on recombinant antigen appears to be a promising advance in the serological diagnosis of acute toxoplasmosis.

Acute Disease↗
PubMed1987

Significance of quantitative enzyme-linked immunosorbent assay (ELISA) results in evaluation of three ELISAs and Western blot tests for detection of antibodies to human immunodeficiency virus in a high-risk population.

The characteristics of primary (first) tests with three enzyme-linked immunosorbent assay (ELISA) kits for human immunodeficiency virus (HIV) antibody were determined. The three ELISAs were performed on 3,229, 3,130, and 685 specimens from high-risk individuals using the Litton (LT; Litton Bionetics Laboratory Products, Charleston, S.C.), Dupont (DP; E. I. du Pont de Nemours & Co., Inc., Wilmington, Del.), and Genetic Systems (GS; Genetic Systems, Seattle, Wash.) kits, respectively. Evaluation was based on the distribution of quantitative test results (such as optical densities), a comparison with Western blot (WB) results, reproducibility of the tests, and identification of seroconverters. The performances of the GS and the DP kits were good by all four criteria and exceeded that of the LT kit. Primary ELISA-negative results were not always confirmed with repeat ELISA and by WB testing. The largest percentage of these unconfirmed negative test results came from samples with quantitative results in the fifth percentile nearest the cutoff. Thus, supplementary testing was indicated for samples with test results in this borderline negative range. Similarly, borderline positive primary ELISA results that were quantitatively nearest (fifth percentile) the cutoff value were more likely to be antibody negative on supplementary testing than samples with high antibody values. In this study, results of repeated tests by GS ELISA showed the least change from first test results. DP ELISA showed more unconfirmed primary positive test results, and LT ELISA showed more unconfirmed primary negative test results. Designation of a specimen with a single ELISA quantitative level near the cutoff value as positive or negative should be viewed with skepticism. A higher than normal proportion of specimens with high negative optical densities by GS ELISA (fifth percentile nearest the cutoff) and also negative by WB were found to be from individuals in the process of seroconversion.

Antibodies, Viral↗
PubMed1991

Comparative evaluation of an enzyme-linked immunosorbent assay (ELISA) to detect antibodies directed against glycoprotein I of pseudorabies virus and a conventional ELISA and neutralization tests.

To determine whether a newly developed enzyme-linked immunosorbent assay (ELISA), which detects antibodies directed against glycoprotein I (gI) of pseudorabies virus, is suitable for serodiagnosis, it was compared with a conventional ELISA and two neutralization tests. The gI ELISA was 99.2% as sensitive and 100% as specific as the conventional ELISA. Antibody titers measured by the gI ELISA were lower than those measured by the conventional ELISA, comparable to those measured by the 24-h neutralization test, and higher than those measured by the 1-h neutralization test. After experimental infections in pigs, antibodies were first detected by the gI ELISA on postinoculation day (PID) 14, by both neutralization tests on PID 7, and by the ELISA on PID 10. All four tests showed the same rate of decline of maternal antibodies in pigs born to sows that had been vaccinated with inactivated vaccine. Thus, not only is the gI ELISA unique in being able to differentiate infected pigs from those vaccinated with gI-negative vaccines, but it is also as useful as a conventional ELISA and as neutralization tests for serodiagnosis.

Animals↗
PubMed1992

Immunodiagnosis of human cysticercosis (Taenia solium): a field comparison of an antibody-enzyme-linked immunosorbent assay (ELISA), an antigen-ELISA, and an enzyme-linked immunoelectrotransfer blot (EITB) assay in Peru. The Cysticercosis Working Group in Peru (CWG).

We compared results of an enzyme-linked immunosorbent assay (ELISA) and an enzyme-linked immunoelectrotransfer blot (EITB) assay for the diagnosis of cysticercosis in sera and cerebrospinal fluid (CSF). Sera from 34 patients with confirmed cysticercosis were tested by both ELISA and EITB assays. Cerebrospinal fluid from some of these patients was also tested by ELISA for the presence of antibody (AB-ELISA) (n = 21) and antigen (AG-ELISA) (n = 15). Specificity in sera was examined by testing 51 serum samples from Bangladesh, where cysticercosis is not endemic. Cross-reactivity was evaluated in sera from patients with Echinococcus granulosus (hydatid) and Hymenolepis nana infections. Sensitivity in detecting cysticercosis in sera was 94% by EITB and 65% by AB-ELISA (P less than 0.01). Sensitivities in the CSF tested by EITB, AB-ELISA, and AG-ELISA were 86%, 62%, and 67%, respectively. The specificity of the EITB was 100%, while that of AB-ELISA was 63% (P less than 0.01). Cross-reactions occurred in the AB-ELISA with 11% and 20% of sera from hydatid and H. nana patients, respectively. Our results demonstrate that the EITB is the best assay available for the diagnosis of cysticercosis in both sera and CSF.

Animals↗
PubMed1992

Cell surface proteins of Helicobacter pylori as antigens in an ELISA and a comparison with three commercial ELISA.

Cell surface proteins of Helicobacter pylori were solubilized by extraction with acidic glycine buffer, N-octyl-glucoside, lithium chloride, and distilled water, and by sonication. The preparations were evaluated as antigens in ELISA to detect serum IgG responses in patients and healthy subjects. SDS-PAGE analyses of the preparations from a type strain (NCTC 11637) and of acidic glycine extracts of 4 clinical isolates showed multiple protein bands. The sera were classified as HP+ve and HP-ve by culture of biopsy and immunoblotting. Sera were considered positive for H. pylori if they detected the specific 120kD antigen or 4-5 other bands. 49 sera were HP+ve; the 51 HP-ve sera did not react in immunoblotting. 35/44 sera (80%) that reacted with the 120kD antigen demonstrated high titers in ELISA with all antigen preparations, and the remaining 9(20%) sera gave discordant results. 4/5 HP+ve sera that did not react with the 120kD antigen, demonstrated high ELISA titers with all 5 antigen preparations. Glycine extracts of 3 isolates did not exhibit the 120kD protein, but were equally sensitive in ELISA. The role of 120kD antigen in our ELISA was not clear. Immunoblotting demonstrated that the 5 antigen preparations share similar antigenic components. All preparations were similarly high in sensitivity and specificity, indicating that surface antigens could be satisfactorily used in our ELISA. Our ELISA using the glycine extract was compared with commercial H. pylori ELISAs developed by Bio-Rad Laboratories, USA (GAP ELISA), Roche, Switzerland (EIA 2G), and Whittaker Bioproducts, USA (Pyloristat).(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Bacterial↗
PubMed1986

Determination of IgM and IgG antibodies to Toxoplasma using the IFA test, ELISA, and Dot-ELISA procedures.

The dot enzyme-linked immunosorbent assay (Dot-ELISA) and the enzyme-linked immunosorbent assay (ELISA) were compared with the immunofluorescent antibody test (IFA) for detection of IgM- and IgG-specific antibodies to human toxoplasmosis. Reciprocal titers were determined in all three assays using sera from 56 patients with suspected toxoplasmosis or with symptoms and diseases requiring exclusion of toxoplasmosis and control sera from 56 healthy persons. Using the Dot-ELISA, six patient sera (10.7%) were positive at titers of greater than equal to 1024 for IgM antibodies (titer range 1024-16 384) and 47 sera (84%) were positive for IgG antibodies (titer range 16-262 144) at a titer of greater than or equal to 16. One control serum was reactive for IgM (titer 1024) and 10 control sera (18%) were positive for IgG in the Dot-ELISA. In the ELISA, at titers of greater than or equal to 128, five sera (9%) were reactive for IgM (titer range 128-512) and 52 sera (92.8%) were reactive for IgG (titer range 32-8192) at a titer of greater than or equal to 32; no control sera gave positive reactions for IgM while 10 sera (18%) were positive for IgG in the ELISA. Using the IFA test at reciprocal titers of greater than or equal to 16, four sera (7.1%) were positive for IgM (titer range 32-512), and 51 sera (91%) were positive for IgG (titer range 16-8192). None was reactive for IgM, and eight sera (14%) were positive for IgG (titer range 32-128) in the IFA test. The Dot-ELISA correlated well with the IFA test (correlation coefficient = 0.895) and the ELISA correlated slightly higher with the IFA test (correlation coefficient = 0.910) for detection of IgG antibodies to Toxoplasma gondii.

Enzyme-Linked Immunosorbent Assay↗
PubMed1985

A micro-capture ELISA for detecting Mycoplasma pneumoniae IgM: comparison with indirect immunofluorescence and indirect ELISA.

A mu-capture ELISA was developed for detecting Mycoplasma pneumoniae-specific IgM, and compared with an indirect immunofluorescent antibody (IFA) technique and an indirect ELISA. mu-capture ELISA and IFA compared well and were found to be the most sensitive assays. The IFA test can be completed in 2 h whilst the results of the mu-capture ELISA can be available in 24 h. Both tests are amenable to routine diagnostic use and have similar sensitivity. Indirect ELISA was found to be less sensitive and less specific, giving high assay values with several sera having undetectable M. pneumoniae CF antibody or CF antibody in low titre. Serum samples obtained from 11 patients at various times after M. pneumoniae infection showed maximum antibody levels within the first month by all assays, with a gradual fall in amount of IgM with time when assayed by mu-capture ELISA, a more gradual decline by IFA and hardly any decline with indirect ELISA. It was concluded that the indirect ELISA is unsuitable for the investigation of possible M. pneumoniae infection because the sustained high assay values with serum samples taken many months after infection, make interpretation of the test results very difficult.

Antibodies, Bacterial↗
PubMed1989

Indirect immunoglobulin G (IgG) and IgM enzyme-linked immunosorbent assays (ELISAs) and IgM capture ELISA for detection of antibodies to lipopolysaccharide in adult typhoid fever patients in Pakistan.

Sera from 339 adult febrile patients in Pakistan were tested for antibodies to Salmonella typhi lipopolysaccharide by indirect immunoglobulin G (IgG) and IgM enzyme-linked immunosorbent assay (ELISA) and IgM capture ELISA. A total of 55 patients had S. typhi cultured from their blood, 20 had S. typhi cultured from their stool, 24 were blood or stool culture positive for S. paratyphi A, 41 were culture negative but clinically diagnosed as having enteric fever, 41 had gastrointestinal or urinary tract infections, 41 were clinically diagnosed as having malaria, 20 were smear-positive patients with malaria, 58 had respiratory infections, and the remaining 39 individuals were placed in a miscellaneous group who did not have Salmonella infection. The sensitivities of the indirect IgG ELISA, indirect IgM ELISA, and IgM capture ELISA determined with specimens obtained from the blood culture-positive patients with typhoid fever (positive controls) were 80, 64, and 62%, respectively. The specificities of the assays determined with sera from the patients with respiratory infections (negative controls) were 95, 95, and 97%, respectively. The percentage of smear-positive patients with malaria who were positive by these assays was lower than that in the negative control group. The percentages of individuals in the other patient categories who were positive by these tests were between those obtained with the positive and negative controls. Of the positive controls, 26 were positive by both IgM assays, 9 were IgM positive only by indirect ELISA, and 8 were IgM positive only by IgM capture ELISA. A total of 70% of the positive control patients who were tested for O agglutinins by the Widal tube agglutination assay were positive; however, 29% of the negative control patients were also positive. The indirect IgG ELISA was the single most effective test for the serodiagnosis of typhoid fever in this population.

Adolescent↗
PubMed1989

Comparison of competitive ELISA, indirect ELISA and standard AGID tests for detecting blue-tongue virus antibodies in cattle and sheep.

The performances of a competitive enzyme-linked immunosorbent assay (ELISA) using a group specific monoclonal antibody against bluetongue virus, an indirect ELISA and the standard agar gel immunodiffusion (AGID) test were compared in the detection of serum antibody against bluetongue virus. Test sera consisted of 1300 bovine, 530 ovine and 160 carpine samples from bluetongue-free areas of Canada, 605 bovine and ovine field samples from the USA and Barbados and 464 samples from 79 cattle and sheep experimentally infected with 19 South African and five USA serotypes of bluetongue virus. The diagnostic specificity of the competitive ELISA, as determined for the bluetongue virus-free cattle sera was superior (99.92 per cent) to that of the indirect ELISA (99.85 per cent) and the AGID (99.0 per cent). The specificities of the competitive ELISA for sheep (99.63 per cent) and goats (100.0 per cent) sera were also higher than those of the AGID test. The performance of the ELISA tests was similar whether a gamma-ray-irradiated (2.0 Mrad) or a non-irradiated bluetongue virus antigen preparation was used. The competitive ELISA results for bovine field sera from endemic areas demonstrated a relatively low level of agreement (92.04 per cent) with AGID test results, with 9.7 per cent false negatives. The possible presence in these sera of antibody to cross-reacting antigens or to other orbiviruses, eg, epizootic haemorrhagic disease virus, which react in the AGID but not in the competitive ELISA may account for this lack of agreement.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

R-ELISA: repeated use of antigen-coated plates for ELISA and its application for testing of antibodies to HIV and other pathogens.

In this paper we report on the evaluation of several procedures that allow for the repeated use of an antigen-coated, enzyme-linked immunosorbent assay (ELISA) plate for enzyme immunoassay (EIA). We have shown that antigen-coated ELISA plates that were incubated once with an aqueous solution containing 8 M urea, 2% sodium dodecyl sulfate and 2% mercaptoethanol, after an EIA, can be reused again for EIA without loss of antigenic capacity. Thus, in this procedure, after an EIA, the ELISA plates were washed once with the above solution and then in a buffer containing 20 mM Tris-HCl, pH 7.5, 0.1% Tween 20 and 500 mM NaCl. This washing protocol was shown to remove the primary antibody, enzyme-conjugated secondary antibody and substrate without removing the antigen from the ELISA plate microwells. Thus, an antigen-coated ELISA plate previously used for an assay could be reused. We tested this repeat ELISA (R-ELISA) procedure on high antigen-binding ELISA plates coated with two different plant virus proteins, a synthetic peptide, the p25/24 gag and the gp120 proteins of the human immuno-deficiency virus, or the staphylococcus enterotoxin protein. In each case tested, the procedure allowed for the repeated use of the same antigen-coated plates for EIA of the respective antibodies. This procedure should prove to be particularly valuable for mass screening of samples tested for HIV and other disease-causing agents.

Amino Acid Sequence↗
PubMed1991

Evaluation of ELISA and GM1-ELISA for detection of Salmonella enterotoxin.

The ELISA and GM1-ELISA, by using antiserum to purified Salmonella enterotoxin (SE), were standardized and carried out to screen salmonellae isolated from foods of animal origin for enterotoxigenicity. Of the 101 strains of Salmonella belonging to 15 different serogroups tested, 76 (75.24%) strains from 13 serogroups were found enterotoxigenic. ELISA correlated well with rabbit ligated ileal loop (RLIL) test for the detection of enterotoxin producing salmonellae with 24 test strains. ELISA also yielded positive reaction with 7 of 13 RLIL negative strains. GM1-ELISA could not be carried out as none of the 101 cell free culture supernatants (CFCS) were able to bind with GM1-ganglioside. ELISA and GM1-ELISA were also standardized with antiserum to cholera toxin for the detection of salmonellae producing cholera related enterotoxin. None of the 101 strains was found to produce cholera related enterotoxin. ELISA could detect as low as 15 ng/100 microliters of purified SE and 10 ng/100 microliters of cholera toxin when tested with their homologous antisera.

Cholera Toxin↗
PubMed1991

Diagnostic values of ELISA-IgG4 as compared to ELISA-IgG and indirect immunofluorescence, for the routine diagnosis of bancroftian filariasis in the South Pacific. Application on capillary blood collected on filter paper.

For the serodiagnosis of lymphatic filariasis, serological assays restricted to the detection of specific IgG4 antibodies enhanced the specificity. In French Polynesia, Wuchereria bancrofti is the sole human filaria and other pathogenic parasites are infrequent. In order to define a simple and cheap serological test, we have compared the diagnostic value of indirect immunofluorescence test (IFI-WBp), ELISA-IgG and ELISA-IgG4 assays. The specificity, sensitivity, R.O.C. curves of each test have been analyzed. No significant difference was found between those 3 tests, except that the reproducibility and the predictive value were lower using IFI-WBp than using the two ELISAs. Significant correlation was found between IgG and IgG4 anti-Brugia malayi antibody titers (r = 0.512, p less than 10(-5)). For large scale seropidemiological studies, ELISA-IgG can be performed with finger prick blood absorbed on filter paper, but not ELISA-IgG4. In conclusion, ELISA-IgG a less expensive and less time consuming method than ELISA-IgG4, can be used for the routine serodiagnosis as well as for seroepidemiological studies on bancroftian filariasis in the South Pacific islands.

Animals↗
PubMed1991

The association of "standard ELISA" and HIV (env) ELISA for detection and confirmation of HIV antibodies in human sera.

Sera from various population of subjects, including patients with AIDS and ARC, drug-addicts seropositive for HIV and healthy blood donors were screened with "standard ELISA" and HIV (env) ELISA. In the present study all 80 specimens from patients with AIDS and all 60 patients with ARC were positive by HIV (env) ELISA, and 1507 specimens from HIV drug positive by W.B. were detected as positive by HIV (env) ELISA. The specificity of HIV (env) ELISA was defined in terms of percentage of non-reacting persons in a low risk population is 100%. Furthermore the HIV (env) ELISA is highly specific and sensitive and could be used in association with "standard ELISA" for detection and confirmation of HIV antibodies in human sera and plasma.

AIDS Serodiagnosis↗
PubMed1990

Comparison of Dot-ELISA with Sandwich ELISA in detecting circulating antigen in patients with bancroftian filariasis.

Dot-ELISA assay was compared with standard Sandwich ELISA in detecting parasite antigen in sera from patients with bancroftian filariasis. The same monoclonal antibody and the same serum samples were used in both assays. With Dot-ELISA, 67 of 70 serum samples from microfilaremic patients were positive at a dilution of 1:50. End titers ranged from 1:80 to 1:1 280. While with Sandwich ELISA, 64 of the 70 serum samples were positive at a dilution of 1:10. End titers ranged from 1:10 to 1:320. The specificity of both assays was over 91%, but their sensitivity was markedly different. Dot-ELISA could detect as little as 0.055 ng/ml microfilarial antigen added to normal human serum, whereas the lower limit of detection by Sandwich-ELISA was 10 ng/ml parasite antigen. An additional advantage of Dot-ELISA is that it does not require radioactivity or sophisticated equipment and, therefore, can be performed in virtually all filariasis-endemic areas.

Animals↗
PubMed1990

Comparison of Dot-ELISA with Sandwich-ELISA for the detection of circulating antigens in patients with bancroftian filariasis.

We compared the performance of a newly developed Dot-ELISA with that of a previously described Sandwich-ELISA to detect parasite antigens in sera from patients with bancroftian filariasis. The same monoclonal antibody and the same sera were used in both tests. In the Dot-ELISA, 67 of 70 sera from microfilaremic donors were deemed to contain filarial antigens when screened at a dilution of 1:50. End titers were 1:80-1:1280. With the Sandwich-ELISA, 64 of the same sera were positive at a dilution of 1:10 and 42 were positive at a dilution of 1:50. End titers were 1:10-1:320. The specificity of both assays was greater than 95%, but their sensitivity was remarkably different. The Dot-ELISA could detect as little as 0.055 ng/ml microfilarial antigen added to normal human sera, whereas the lower limit with the Sandwich-ELISA was 10 ng/ml parasite antigen. Additionally, the Dot-ELISA does not require radioactivity or sophisticated equipment and, therefore, can be performed in virtually all filariasis-endemic areas.

Animals↗