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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↗
PubMed1985

IFA serological surveys of malaria in north, north-west and south-west parts of Iran.

In the IFA serological surveys of malaria carried out in north, north-west and south-west parts of Iran during 1975-1982 altogether 9,132 subjects were studied for malaria antibodies and parasitaemia. Serological data indicated probable malaria transmission in a consolidation area where the autochthonous cases of malaria were reported a year after this serological study. Asymptomatic parasite carriers of P. malariae were found by IFA and parasite concentration techniques among the professional blood donors and the residents of a village without any recent malaria history. IFA results with P. falciparum antigen reflected the malaria histories in the studied areas of west Azerbaijan better than P. vivax antigen. The serological and parasitological findings in the nomads of Bakhtiary tribes showed that the nomads are more exposed to malaria infection in the winter quarters of Izeh area and they are also more under malaria control programme when they are living in this area. In comparison of IFA results of 438 paired plasma and dried blood samples tested with P. vivax and P. falciparum antigens, there was no significant difference between SPR in plasma and dried blood samples, however in the dried blood samples collected by malaria surveillance agents on filter paper SPR and GMRT were considerably low.

Adolescent↗
PubMed1985

Comparison between IgM-IFA and DS-IgM-ELISA performed on IgM fractions and whole sera in acute acquired toxoplasmosis.

The present investigation has shown that antibodies titers obtained by IgM-IFA performed on pure IgM-fractions, obtained by gel-filtration method, correlate well with DS-IgM-ELISA. False negative IgM-IFA results that frequently occurs with sera having greater than or equal to 200 I.U./ml by IgG-IFA, were not observed with DS-IgM-ELISA: and the 98% of sera positive only after separation of IgM fraction with IgM-IFA, are also positive with DS-IgM-ELISA performed on whole serum.

Chromatography, Gel↗
PubMed1980

Comparison of haemagglutination inhibition (HI) and indirect fluorescent antibody (IFA) techniques for the serological diagnosis of certain flavivirus infections.

Paired serum samples from 25 patients having clinical evidence of arboviral infections and 15 controls were examined for antibodies against dengue, Japanese encephalitis and West nile viruses by haemagglutination inhibition (HI) and indirect fluorescent antibody (IFA) methods. The two tests were comparable in specificity but the IFA test was found to be more sensitive than the HI test. Like the HI test, the antibodies detected by IFA test cross-reacted within the flavivirus group under test. Use of IFA test is recommended to detect flavivirus infections as the test is simple, sensitive and can be carried out rapidly.

Arbovirus Infections↗
PubMed1975

An evaluation of the IFA-GC procedure in a low risk population.

An automated indirect fluorescent antibody (IFA) test for gonococcal antibody was evaluated in 600 low risk females; 392 were prenatal patients from public and private clinics and 208 were apparently healthy females state employees in a multiphasic screening program. Clinical histories, physical examinations, and cervical cultures were obtained on all patients. The results of the cultures and serologic test were compared. Although the number of culture positive patients in the study was low, the lack of sensitivity of the IFA test in detecting gonococcal infection in these patients was disturbing. This observation and the number of apparent false positive IFA tests lead us to conclude that the automated IFA test for detection of gonorrhea shows promise, but we could not consider adopting the test in its present stage of development.

Antibodies↗
PubMed1980

A comparison of the IFA and the ELISA for the demonstration of antibodies against schistosome gut-associated polysaccharide antigens in schistosomiasis.

The applicability of two immunodiagnostic techniques was studied for the detection of antibodies against schistosome gut-associated polysaccharide antigens in human schistosomiasis mansoni: the immunofluorescent antibody reaction (IFA) using Rossman's fixed paraffin sections of adult worms and the enzyme-linked immunosorbent assay (ELISA) with a trichloroacetic acid soluble fraction of total adult worm antigens (AWA-TCA). With the IFA, gut-associated polysaccharide antigens could be demonstrated with an anti-IgM conjugate in a high percentage of the sera tested, although false-negative reactions were occasionally recorded. The use of an anti-IgG conjugate resulted in the demonstration of antibodies against additional antigens in the parenchyma of the worm and on the tegument. Specific IgM antibodies were present in higher concentrations in the sera from children than in those from adults. Using AWA-TCA as the antigen preparation in the ELISA, only antibodies against the circulating anodic antigen (CAA) could be demonstrated. Pretreatment of the ELISA-plates with poly-L-lysine to couple AWA-TCA was not necessary. The ELISA was successfully applied with anti-Ig, anti IgG, and anti-IgM conjugates. With anti-Ig conjugate the test was very sensitive and gave less false-negative reactions than the IFA. There was a significant difference between Ig, IgG, and IgM titres of children and adults. The use of an immunogalactosidase assay with a fluorogenic substrate in the ELISA, resulted in a test which was able to detect antibodies at ten times higher dilutions than with the immunoperoxidase assay.

Adolescent↗
PubMed1986

Serodiagnosis of human G and M immunoglobulins to Toxoplasma gondii by ELISA using whole tachyzoites as antigens: a comparative study with the indirect haemagglutination (IHA) and immunofluorescence (IFA) tests.

An indirect ELISA using whole tachyzoites of Toxoplasma gondii fixed onto the bottom of microtiter plate wells is described for detection of specific G and M anti-toxoplasma antibodies. ELISA results were compared with those of IFA and IHA tests. Similarity of antigens (cell surface) involved in ELISA and IFA permits high correlation between the two tests (r = 0.84-0.93, P less than 0.001) and results in good accordance for negative sera. As ELISA offers several advantages over the classical IFA test, it may be considered an alternative method for screening of G and M anti-toxoplasma antibodies.

Animals↗
PubMed1987

Cytoplasmic intermediate filament proteins and the nuclear lamins A, B and C share the IFA epitope.

The murine monoclonal antibody IFA isolated by Pruss et al. (Cell 27 (1981) 419) reacts with all major proteins of the cytoplasmic intermediate filament family (IF) albeit with different affinities but leaves the nucleus undecorated in standard immunofluorescence microscopy. Here we show that IFA reacts with all three nuclear lamins from rat and man in immunoblotting. This is most easily demonstrated in a cell line in which most cells lack cytoplasmic IFs. Thus the rather minor but ubiquitous 66 kD polypeptides identified by Pruss et al. as IF-associated proteins reflect the lamin triplet. While surprising at first, these results are in agreement with the approximate location of the IFA epitope on IF molecules and the recently discovered sequence homology along the rod domain between lamins A and C and IF proteins. Our results extend this relation to lamin B in spite of its unique behaviour during mitosis.

Animals↗
PubMed1999

Evaluation of methodologies including immunofluorescent assay (IFA) and the polymerase chain reaction (PCR) for detection of human pathogenic microsporidia in water.

Microsporidia is a term used to describe a group of emerging protozoan pathogens whose environmental occurrence has only recently been documented due to lack of detection methodologies. This study evaluates and describes current methods for detection of microsporidia in water. Standard methods, for the collection and processing of large volumes of water to detect protozoa, showed only a 4.8% recovery, of microsporidia spores, from 100 l volumes of tap. Immunofluorescent assay (IFA) analysis was assessed using two different antibodies specific for human pathogenic microsporidia. Results indicated that the use of IFA for routine screening of water for microsporidia was not an acceptable approach. The antibodies tested for the IFA resulted in false positives and false negatives and did not react with Enterocytozoon bieneusi, which is an important human pathogenic microsporidia. Finally, the small sizes of the human pathogenic microsporidia prevent confirmation and species determination by light microscopic methods. Two methods for isolating microsporidia DNA from water for use in polymerase chain reaction (PCR) amplification of microsporidia target sequences were assessed. Both of these DNA isolation methods when combined with the PCR showed the ability to detect less than ten spores in purified water concentrates. Thus, this study represents the first documentation and evaluation of current methods for the detection of human pathogenic microsporidia in water.

Animals↗
PubMed2006

Comparative evaluation of antibody positive titer by ELISA and IFA in Theileria annulata vaccinated cattle in Iran.

An enzyme linked immunosorbent assay (ELISA) was used to evaluate antibody positive titer in vaccinated and non-vaccinated cattle using schizont infected myeloid cells as an antigen. The result was compared with indirect fluorescent antibody level in the same animals. For this study 116 milking cows, 95 vaccinated and 21 non-vaccinated, were bleeded in order to prepare sera. They were tested with both ELISA and IFA tests. 94 sera had positive antibody titer and 22 sera were negative through ELISA test but, with IFA test, only 89 sera showed positive antibody titer and 27 were negative. Thereby, it was concluded that the sensitivity and specificity of ELISA test in comparison with IFA test was 95.5% and 66.6% respectively. This study generally indicated that ELISA could be an effective test for sero-epidemiological investigations of bovine tropical theileriosis, and it is considered to be valid as an additional test to distinguish the vaccinated from the non vaccinated cattle in order to schedule vaccination programs.

Animals↗
PubMed1993

Application of a recombinant baculovirus expressing hantavirus nucleocapsid protein as a diagnostic antigen in IFA test: cross reactivities among 3 serotypes of hantavirus which causes hemorrhagic fever with renal syndrome (HFRS).

Recombinant baculovirus-infected insect cells which expressed recombinant protein, analogous to the nucleocapsid protein (NP) of Seoul type hantavirus, strain SR-11 (rNP-SR-Sf9) were applied to the indirect immunofluorescent antibody (IFA) test. The rNP-SR-Sf9 reacted with anti NP MAb clones which recognized strain specific or hantavirus common epitopes in the IFA test. The recombinant antigen was detected by antibodies to 3 serotypes of hantaviruses (Hantaan 76-118, SR-11, Puumala). Antibody titers of a group of experimentally infected mouse and urban rat sera using rNP-SR-Sf9 and strain SR-11-infected Vero cell antigens were mutual correlative. These results indicated that the rNP-SR-Sf9 were an effective and safety substitute for Vero E6 cells in the IFA test for serosurveys of hantavirus infection.

Animals↗
PubMed1992

Retrospective serologic survey for the presence of feline immunodeficiency virus antibody: a comparison of ELISA and IFA techniques.

A total of 878 samples from the New York State Diagnostic Laboratory (NYSDL), dating from January 1984 to May 1987, were examined to detect antibodies to feline immunodeficiency virus (FIV). We used 2 screening methods; an indirect immunofluorescence assay (IFA) and an enzyme-linked immunosorbent assay (ELISA). Of these, 211 samples were from cats that tested negative for feline leukemia virus (FeLV) and exhibited disease signs consistent with immunodeficiency disease; 19 (9.0%) serum samples were determined to be positive. An additional 508 samples were from cats that tested FeLV-negative and were asymptomatic; 6 (1.2%) sera were determined to be positive. The final 159 samples were from FeLV-positive cats and included symptomatic and asymptomatic animals; this population of cats produced 6 (3.8%) positives. Additionally, 521 samples from the Cornell Feline Health Center (CFHC) serum bank, dating back to 1966, were tested to determine the earliest sample in which FIV antibodies could be detected. Five (2.7%) 1971 and 3 (3.3%) 1969 CFHC samples tested positive. The IFA for FIV antibody proved to be a sensitive (97.4%) and specific (100%) test. The ELISA also had high sensitivity (100%) and specificity (99.6%); however, the IFA proved to be more specific than the ELISA when assaying FeLV-positive cats.

Animals↗
PubMed2004

Ex vivo detectable activation of Melan-A-specific T cells correlating with inflammatory skin reactions in melanoma patients vaccinated with peptides in IFA.

The purpose of this study was to test melanoma vaccines consisting of peptides and immunological adjuvants for optimal immunogenicity and to evaluate laboratory immune monitoring for in vivo relevance. Forty-nine HLA-A2 positive patients with Melan-A positive melanoma were repeatedly vaccinated with Melan-A peptide, with or without immune adjuvant AS02B (QS21 and MPL) or IFA. Peptide-specific CD8 T cells in PBLs were analyzed ex vivo using fluorescent HLA-A2/Melan-A multimers and IFN-gamma ELISPOT assays. The vaccines were well tolerated. In vivo expansion of Melan-A-specific CD8 T cells was observed in 13 patients (1/12 after vaccination with peptide in AS02B and 12/17 after vaccination with peptide in IFA). The T cells produced IFN-gamma and downregulated CD45RA and CD28. T-cell responses correlated with inflammatory skin reactions at vaccine injection sites (P < 0.001) and with DTH reaction to Melan-A peptide (P < 0.01). Twenty-six of 32 evaluable patients showed progressive disease, whereas 4 patients had stable disease. The two patients with the strongest Melan-A-specific T-cell responses experienced regression of metastases in skin, lymph nodes, and lung. We conclude that repeated vaccination with Melan-A peptide in IFA frequently leads to sustained responses of specific CD8 T cells that are detectable ex vivo and correlate with inflammatory skin reactions.

Adolescent↗
PubMed1991

Comparative evaluation of an ELISA based on recombinant polypeptides and IFA for serology of malaria.

In the present investigation we compare the performance of a solid-phase assay based on three recombinant polypeptides corresponding to three asexual blood-stage antigens of P. falciparum (ELISA MIXT) with the reference method for the measurement of antimalaria antibodies: indirect immunofluorescence antibody assay (IFA). Sera collected from persons with various degrees of exposure to malaria were selected: sera from inhabitants of a malaria endemic area (Group I), European patients with acute malaria infection (Group II) and blood donors with clinical symptoms of sickness or fever during a stay in malaria endemic areas. 86% of the sera gave concording results by ELISA MIXT and IFA. The correlation was 100% for sera of Group I but discrepancies were observed for Groups II and III. The great majority of the differences were due to sera positive on ELISA MIXT but not by IFA. Most of the sera positive on ELISA MIXT reacted with parasite-derived components only on Western-blot. These results underline the potential of the ELISA MIXT for epidemiologic studies.

Adolescent↗
PubMed1989

[Modified IFA assay in diagnosis of legionellosis].

IFA and modified IFA assay were used for the antigen-antibody reaction between L. pneumophila type I, II to VI and their anti-sera as well as anti-sera of other related bacteria, and between 31 strains of pneumonic pathogens and various types of Lp-antisera. The same results were obtained by using these two methods. 46 pneumonia cases with paired sera and 116 normal sera were examined for Lp-antibody. The results obtained by both were almost the same. It was shown that the modified IFA assay was sensitivity and specific as the original one, and it could be used in laboratory for the diagnosis of Legionellosis.

Antibodies, Bacterial↗
PubMed1988

[Comparison of the IFA, ELISA IgG, ELISA IgM, IHA and the direct agglutination tests in Toxoplasma gondii serology].

In this study, toxoplasma antibodies were evaluated by using IFA, ELISA IgG, ELISA IgM, IHA and direct agglutination test in serum samples obtained from reproductive women. The specificity, sensitivity, unit costing and timing of tests compared with IFA test. In this evaluation IFA test are used. ELISA IgG specificity 98%, sensitivity 97.5%; IHA specificity 90%, sensitivity 97.5%; direct agglutination specificity 92%, sensitivity 95% have been found.

Agglutination Tests↗
PubMed1983

Indirect immunofluorescence assay (IFA), microagglutination test (MA) and enzyme-linked-immunosorbent assay (ELISA) in diagnosis of legionellosis.

Lipopolysaccharide was extracted with cold phenol water from Legionella pneumophila and used as antigen for ELISA. IgG and IgM antibodies were measured with the ELISA and the immunofluorescence assay (IFA). Agglutinating antibodies were measured by the microagglutination (MA) test. In tests on sera from 27 patients with confirmed Legionella infections predominantly due to L. pneumophila serogroup 1 the results with the ELISA, the IFA and the MA were compared to each other. Antibody titers obtained by the ELISA were in general much higher than those obtained by both other tests. The ELISA proved to be the most sensitive method (IgG: 91.3%, IgM: 52.2%) whereas the sensitivities of IFA and MA were IgG: 69.6%, IgM: 30.4% and 60.9%, respectively. There was low correlation of the IgG antibody titers but good correlation of the IgM titers. Further 49 sera from patients without Legionella infection were screened to calculate the specificities of the three tests which were equally good with all methods (98%).

Agglutination Tests↗
PubMed2006

Comparison of immunofluorescence assay (IFA) and LIAISON in patients with different clinical manifestations of Lyme borreliosis.

Serological tests for detection of borrelial antibodies are frequently used in laboratory diagnostics of Lyme borreliosis. Unfortunately these tests are not standardized and the results obtained with different assays may not be concordant. The aim of the present study was to compare two different serological tests, IFA and LIAISON, for detection of Borrelia burgdorferi sensu lato IgM and IgG antibody. We analyzed the serological immune response in 383 patients with different clinical manifestations of Lyme borreliosis and in 49 healthy blood donors. LIAISON detected IgM and IgG antibodies more often than IFA in all groups of patients except those with chronic Lyme borreliosis. The differences were significant for IgM and IgG antibodies in patients with solitary erythema migrans and in those with early disseminated Lyme borreliosis. There was no significant difference in the specificity of the two tests.

Antibodies, Bacterial↗