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At least 19 recordsLinked to original sources
PubMed1990

Imported fire ant (IFA) sensitivity: IFA-specific levels of serum IgG and IgG4.

Imported fire ant (IFA) whole body extract (WBE) and venom (V)-specific IgG and IgG4 antibodies and specific IgE antibodies were evaluated in sera from 56 IFA-sensitive individuals (18 undergoing immunotherapy with IFAWBE and 38 individuals not being treated) and 44 nonatopic and atopic control subjects with no history of IFA allergy. Although there was no difference in the level of IFAWBE- or IFAV-specific IgG between treated and untreated patients, both groups had higher levels of IFAWBE- and IFAV-specific IgG (p less than 0.05) than did control subjects. Patients receiving treatment tended to have higher levels of IFAWBE-specific IgG4 than did either untreated patients (0.05 less than p less than 0.10) or control subjects (p less than 0.05). Levels of IFAV-specific IgG4 were higher in treated patients than in control subjects (p less than 0.05) but were not different between treated and untreated patients. Levels of IFAWBE- and IFAV-specific IgE antibodies did not differ between the two patient populations but were higher in both groups than in control subjects (p less than 0.05). The ratio of IgG4 to IgE (G4/E) for both IFAWBE and IFAV was calculated for all groups. The ratios of IFAWBE- and IFAV-specific G4/E were higher in treated patients and in control subjects as compared to nontreated patients (p less than 0.05). IFAV-specific G4/E ratios were lower in treated patients than in control subjects, but IFAWBE-specific G4/E ratios were the same as ratios for control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMed1992

Microinjection of IFA antibody induces intermediate filament aggregates in epithelial cell lines but perinuclear coils in fibroblast-like lines.

The murine monoclonal IFA antibody recognizes a conserved sequence present in almost all intermediate filament (IF) proteins. When IFA antibody was injected into 13 different primary or established cell lines, striking differences were detected between epithelial and fibroblastic cell lines. In epithelial cells keratin IFs were broken down within 4 h into numerous spheroid aggregates scattered throughout the cytoplasm. Keratin aggregates were first detected in the cytoplasmic periphery. In contrast, in fibroblastic cells, injection of IFA antibody led to the formation of perinuclear coils of vimentin. IFA antibody at a concentration of greater than 1 mg/ml had to be injected to initiate these transitions. When HeLa cells, which contain separate networks of vimentin and keratin filaments, were injected with IFA antibody, vimentin did not form perinuclear coils but was instead found together with keratin in aggregates. Electron micrographs of HeLa cells injected with IFA antibody showed that the aggregates have diameters between 0.5 and 2.6 microns and resembled the keratin aggregates observed in certain mitotic epithelial cells. Although the ultrastructural studies support an association of some aggregates with desmosomes, aggregates were, however, also induced by injection of IFA antibody into human keratinocytes in low calcium medium under conditions where desmosomes were not present.

3T3 Cells↗
PubMed1976

Comparison of indirect fluorescent antibody (IFA) with complement fixation (CF) tests for diagnosis of Babesia spp infections in Colombian cattle.

A total of 372 serum samples were collected from Colombian cattle before and during the course of natural Babesia spp. infection on the North Coast of Colombia. The serum samples were used to compare indirect fluorescent antibody (IFA) with complement fixation (CF) tests for diagnosis of babesiosis. The IFA technique detected Babesia argentina antibodies an average of 4.0 weeks earlier than the CF test and Babesia bigemina an average of 2.5 weeks earlier. Both IFA and CF were capable of differentiating B. argentina and B. bigemina infections, however in some cases cross reactions were observed. In general IFA titers were at relatively high levels of 1:640 to 1:5120 in comparison with CF titers of trace to 1:80. In cases of mortality due to babesiosis, both IFA and CF serologic techniques were very useful in indicating the cause of death. Although both IFA and CF are laboratory tests, the IFA technique had advantages over the CF in simplicity, economy and speed of performance.

Animals↗
PubMed1986

False positive indirect fluorescent antibody (IFA) tests for antibody to herpes simplex virus 1. Comparison of four commercially available methods.

Four commercially available herpes simplex virus 1 (HSV-1) indirect fluorescent antibody (IFA) kits were compared with the use of sera selected because they were negative for HSV antibody by complement fixation (CF less than 1:8) and by ELISA (less than 1:100). However, 14 of 24 (58.3%) of these HSV-1 antibody-negative sera were positive at greater than or equal to 1:10 with the use of the HSV-1 IFA kit from Electronucleonics, 15 of 24 (62.5%) were positive with the Clinical Sciences HSV-1 IFA kit, 4 of 24 (16.7%) were positive with Zeus Scientific, and 4 of 18 (22.2%) were positive with the Gull Laboratories product. HSV-1 induces Fc receptors that commonly cause false positive IFA tests for HSV antibody. Therefore, further studies were undertaken to determine whether Fc receptors accounted for these false positive results. Staphylococcal protein A (SPA) is known to bind to the Fc portion of human IgG and therefore could be used to distinguish between the binding of an antibody by its Fab or its Fc portion. Thus, when fluorescein isothiocyanate conjugated (FITC) SPA was used as conjugate instead of FITC antibody to human IgG, true HSV-1 antibody-containing sera remained positive, but the false positives identified in the commercial IFA kits did not. The authors conclude that HSV-1-induced Fc receptors are responsible for most of the problem of these false positives and that HSV-1 serology probably should not be done by this type of IFA method until this problem is corrected.

Antibodies, Viral↗
PubMed1991

Cloning of the non-neuronal intermediate filament protein of the gastropod Aplysia californica; identification of an amino acid residue essential for the IFA epitope.

We describe the isolation and characterization of a full-length cDNA corresponding to the larger non-neuronal (nn) intermediate filament (IF) protein of the gastropod Aplysia californica. Comparison of the sequences of the nn-IF proteins from Aplysia californica and Helix aspersa shows a strong evolutionary drift. At a 72% sequence identity level, the IF proteins of Opisthobranchia and Pulmonata show a larger distance than vimentins from Xenopus and mammals. The sequence comparison of the two snail proteins provides an important step in understanding the epitope of the monoclonal antibody IFA mapped by previous studies to the consensus sequence at the carboxy-terminal end of the rod domain of IF proteins. We identify for the first time in a naturally occurring IF protein a single amino acid exchange which leads to the loss of the epitope. The consensus sequence YRKLLEGEE present in IFA-positive proteins such as the Helix IF protein is changed in the IFA-negative Aplysia protein only by the conservative substitution of the arginine (R) by a lysine (K). Thus, the IFA epitope is not a necessity of IF structure, and its presence or absence on different IF proteins reflects only small changes in an otherwise conserved consensus sequence. Consequently, lack of IFA reactivity does not exclude the presence of IF. This result predicts that IF are much more universally expressed in lower eukaryotes than currently expected from immunological results with the monoclonal antibody IFA.

Amino Acid Sequence↗
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↗
PubMed1988

RESA-IFA assay in Plasmodium falciparum malaria, observations on relationship between serum antibody titers, immunity, and antigenic diversity.

RESA-IFA assays were conducted using 63 adult sera from 7 different malarious areas against 7 different strains of Plasmodium falciparum, and 28 children's sera against 3 different parasite strains. Generally, where immunity to malaria was high, there was little or no antigenic diversity among the different strains examined. However, where sera were collected from semi-immunes, or from children, some variation in the RESA-IFA endpoint titers was discernible. Correlation between antibody titers determined by RESA-IFA and in vitro parasite invasion inhibition was not complete. Sera having high RESA-IFA titers were predictably inhibitory; however, many sera having low RESA-IFA titers were as inhibitory as sera having high titers, indicating that antibodies with specificities different from the RESA may be as important, or more important, to clinical immunity to blood-stage infections.

Adolescent↗
PubMedDate not supplied

Linkage analysis of the murine interferon alpha locus (Ifa) on chromosome 4.

We performed linkage analysis of the murine interferon alpha gene cluster, Ifa, with three different marker genes on chromosome 4: the major urinary protein locus (Mup-1), the brown locus (b) and the misty locus (m). The gene order (from centromere) with intervening percent recombination derived from a first three-point cross is Mup-1--13.6 (+/- 3.6)--Ifa--7.9 (+/- 2.8)--m and from a second three-point cross Mup-1--1.7 (+/- 1.7)--b--3.5 (+/- 2.4)--Ifa. The combined results indicate that the gene order, from the centromere, is Mup-1--b--Ifa--m.

Animals↗
PubMed1992

[Comparable evaluation of serological diagnostic tests (ELISA, IFA and PA methods) for the detection of anti-Borrelia burgdorferi antibody].

We have evaluated the usefulness of the enzyme-linked immunosorbent assay (ELISA), indirect fluorescent antibody assay (IFA) and particle agglutination (PA) method as serological screening tests for Lyme-borreliosis. Serum samples obtained from two patients with Lyme-borreliosis showed marked high antibody titers for Borrelia burgdorferi when measured by these methods. Of the serum of 368 healthy members of the Self-Defense Force in north-eastern Japan screened for the antibody to B. burgdorferi, 8.4%, 3.7%, 4.6% were found positive by the ELISA, IFA, and PA method, respectively. However, Western blot analysis of these "positive" sera demonstrated no identical bands to those seen in the serum from the patients with Lyme-borreliosis. While 85% and 15% of Treponema pallidum hemagglutination test (TPHA)-positive sera (20 samples) showed a false-positive reaction by the ELISA and IFA method, respectively, no cross-reaction to the anti-B. burgdorferi antibody was observed in these sera by the PA method. The analysis of the serum of the patients with autoimmune diseases (rheumatoid arthritis; 11 cases, systemic lupus erythematosus; 46 cases) by the ELISA and PA methods resulted in a cross-reaction to some extent, which suggested that the antibodies produced by autoimmune mechanisms such as the anticardiolipin antibody can cause a cross-reaction to the anti-B. burgdorferi antibody. These findings indicate that the PA and ELISA rather than the IFA method should be recommended for rapid and conventional screening of Lyme-borreliosis and that serum "positive" for the anti-B. burgdorferi antibody determined by these tests should be confirmed by Western blot analysis to negate the cross-reactions.

Agglutination Tests↗
PubMed1989

The physical separation of Lps and Ifa loci in BXH recombinant inbred mice.

Several reports in the literature suggest that many of the phenotypic defects of LPS-hyporesponsive C3H/HeJ mice may be attributed to decreased IFN production by their macrophages. The physical proximity on chromosome 4 of the gene which encodes sensitivity to LPS (Lps) and the structural gene cluster which encodes IFN-alpha (Ifa), suggests the possibility that the Lps gene, whose product is unknown, may actually be a part of the Ifa gene cluster. The C57BL/6J and C3H/HeJ mouse strains carry distinct alleles at both the LPs and the Ifa loci. In this study, we have analyzed these parental strains, as well as 12 recombinant inbred strains derived from these parental strains (e.g., BXH strains), for inheritance of these distinct alleles. The results show the segregation of these two loci: in 5 of 12 BXH RI strains, the IFN-alpha restriction fragment length polymorphism characteristic of one parental strain was discordant with the predicted LPS response phenotype. Therefore, we conclude that the Lps and the Ifa genes are physically distinct despite the apparent cause and effect relationship which is observed phenotypically.

Animals↗
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↗
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↗
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↗
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↗
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↗