Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “IFA”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 937 records · Page 52Linked to original sources
PubMed1980

Collagen-induced polyarthritis in rats: a study of native type II collagen for adjuvant activity.

Collagen-induced polyarthritis in rats is a new experimental model that shares clinical and histologic features with adjuvant arthritis. To determine whether collagen-induced arthritis is a form of adjuvant disease and to further exclude contamination of collagen with an adjuvant substance, native type II collagen was studied for adjuvant properties. IgM and IgG PFC activity and PBMC [3H]TdR incorporation were studied in rats after injection with TNP-OA combined with IFA, IFA and CII, or CFA. In general, humoral and CMI responses to TNP-OA were lower in rats injected with IFA/CII compared with those with IFA; the presence of CII during primary immunization failed to significantly enhance PFC activity to TNP after a boost. CFA-injected rats gave maximal values in both studies. Mice pretreated with BII in the absence of oil gave PFC responses below control after sensitization with SRC. Furthermore, CII was unable to replace mycobacteria in the induction of EAE in rats and was devoid of mitogenic or polyclonal stimulatory properties. It is concluded that collagen-induced arthritis is a distinct entity from adjuvant arthritis and is dependent upon the unique immunogenicity of type II collagen in rats rather than upon an adjuvant effect.

Animals↗
PubMed1981

Serobiological differentiation between antischistosomal (Schistosoma mansoni) antisera.

Sera from chronically infected mice and from mice immunized with a soluble worm extract were both cytotoxic in vitro to schistosomula and exhibited similar antibody titers when tested by the indirect fluorescent antibody (IFA) technique with unmodified schistosomula. However, only the former type of antiserum was passively protective and highly reactive by IFA technique with schistosomula modified by heat or by successive heat and pronase treatments. These results indicate that in vitro cytotoxic antibody activity and passive protectivity are unrelated antischistosomal activities and suggest therefore that quantitatively or qualitatively different antibodies may be involved in their execution. It is yet unclear whether antibodies to the "treatment resistant" determinants are involved in protection, although they reach maximal expression between 10 and 16 weeks after infection, at which time protective immunity was demonstrable. The treated schistosomula are capable of inducing antibodies in mice and the antisera raised against them exhibited different patterns of activity when cross-tested by the IFA technique with untreated and treated schistosomula. The antigenic hierarchy of the "treatment resistant" determinants is discussed in view of the various serological findings.

Animals↗
PubMed1981

Effect of proteolytic enzymes on Pneumocystis carinii in rat lung tissue.

Rat lung homogenates heavily infected with Pneumocystis carinii were digested with trypsin and pronase. Pneumocystis carinii cysts were examined by light and electron microscopy, and by an indirect fluorescent antibody (IFA) technique. Cysts digested with trypsin exhibited swelling of their cell wall but stained brightly by IFA; cysts digested with pronase lost their cell wall and ability to stain by IFA. These effects were related to the concentration of the enzyme and duration of exposure. The data suggest that the antigenic determinants of P. carinii cysts reside in the cell wall.

Animals↗
PubMed1981

Immunodiagnosis of recently acquired Schistosoma mansoni infection. A comparison of various immunological techniques.

A group of Dutch tourists, who became infected with Schistosoma mansoni in Ethiopia, was investigated in a serological follow-up study, during 8-50 weeks after infection. The following immunodiagnostic tests were applied: (1) the immunofluorescent antibody (IFA) test, both on frozen sections of adult worms, and in a modification for the detection of antibodies against gut-associated polysaccharide antigens; (2) the enzyme-linked immunosorbent assay (ELISA) with as antigens: adult worm antigens (AWA), cercarial antigens (CA), soluble egg antigens (SEA), and the purified antigens CAA and MSA1; (3) the defined antigen substrate spheres system with AWA as antigen in an immunofluorescence and immunoperoxidase modification; (4) the indirect haemagglutination reaction with AWA; and (5) the immunoelectrophoresis with AWA and antigens of the intermediate host. With these techniques it could be shown that in all persons which had been in contact with S. mansoni infected water, also in those not excreting schistosome eggs or not showing clinical symptoms of infection, specific anti-schistosome antibodies were present. No false-negative reactions were found with the ELISA with cercarial antigens, MSA1, or AWA-TCA, with the IFA detecting gut-associated polysaccharide antigens and with the immunoelectrophoresis. The highest titres were observed with the two techniques (IFA and ELISA) detecting antibodies against the gut-associated polysaccharide antigen CAA.

Enzyme-Linked Immunosorbent Assay↗
PubMed1980

A study of variation in the indirect hemagglutination antibody test for toxoplasmosis.

The indirect hemagglutination test (IHA) was compared both qualitatively and quantitatively to that of the indirect fluorescent antibody (IFA) technique for the detection of antibodies to Toxoplasma gondii. The coefficient of correlation between the two methods was +0.9561. Of the 89 samples tested, no significant disagreement between the IFA titers and mean titers of the IHA test was detected. Quantitative evaluation revealed 93.3 percent of the sera positive in both methods were within a one-tube dilution or same dilution, and 100 percent were within a two-tube (four-fold) dilution. A statistical evaluation of internal reproducibility of titer in the IHA test, utilizing 30 paired samples, indicated that titers by this method can be reproduced on a within-day basis within limits of +/- 1 two-fold dilution with 95 percent confidence. Day-to-day reproducibility of titers were 100 percent within limits of +/- 1 four-fold dilution. Because of its high reproducibility, prolonged stability, and ability to produce standardized results, the IHA technique is recommended over the IFA for mass screening.

Animals↗
PubMedDate not supplied

Yersinia-associated arthritis in rats: effect of 65 kDa heat shock protein, bovine serum albumin and incomplete Freund's adjuvant.

OBJECTIVE: We have previously shown that the microbial load of rats has a significant effect on their susceptibility to Yersinia-associated arthritis. In this study our aim was to see whether mycobacterial 65 kDa heat shock protein (hsp) could induce the same suppressive effect in experimental Yersinia-associated arthritis as has been reported for arthritides induced by adjuvant, pristane, or streptococcal cell walls (SCW). METHODS: Arthritis was induced by the intravenous injection of Yersinia enterocolitica 0:8 into Lewis rats. Hsp, bovine serum albumin (BSA) or NaCl, administered in incomplete Freund's adjuvant (IFA), was given subcutaneously on day -5 or +5 with regard to the bacterial inoculation. RESULTS: Mycobacterial hsp given in IFA on day -5 significantly suppressed the development of arthritis. However, a similar suppression was observed with BSA or NaCl given in IFA. CONCLUSION: These results, together with those known from the effect of microbial load, suggest that susceptibility to Yersinia-associated arthritis is easily affected by external factors.

Animals↗
PubMed1995

[Variants and stages in the course of idiopathic fibrosing alveolitis].

Clinicomorphological analysis covered 41 cases of idiopathic fibrosing alveolitis (IFA). The comparison of the degree of respiratory insufficiency, hypoxia, survival of the patients with cytogram of the bronchoalveolar lavage, morphological findings, generation of active oxygen forms by alveolar macrophages and leukocytes has provided evidence on an important role of alveolar macrophage in interstitial alveolitis and fibrosis in IFA. Three variants of chronic IFA are distinguished: aggressive, persistent and slowly progressive. The variants have different prognosis and need individual therapeutic approach.

Adult↗
PubMed1994

Immunodetection of Plasmodium falciparum zygotes and ookinetes in Anopheles blood meals.

An indirect fluorescent antibody assay (IFA) using monoclonal antibodies to the 25-kDa Plasmodium falciparum ookinete surface antigen was developed to detect and quantify preoocyst stages of P. falciparum in mosquito blood meals. This IFA is suitable for the detection and quantitation of zygotes/macrogametes, retorts (immature ookinetes), and ookinetes. Time-course evaluations showed that zygotes represented > 52% of the parasites detected between 6 and 24 h. From 24 to 36 h similar densities of all 3 stages were observed. By 42 h. 56% of the detectable parasites were ookinetes. Compared to the hemocytometer the IFA provided a better estimate of stage-specific infection rates and densities. The assay is a useful new tool for evaluating preoocyst stages in laboratory-infected mosquitoes and has the potential for detecting natural infections in vector populations.

Animals↗
PubMed1994

HIV-1 immunogen induction of HIV-1-specific delayed-type hypersensitivity: results of a double-blind, adjuvant-controlled, dose-ranging trial.

OBJECTIVE: To investigate the capacity of an HIV-1 immunogen to induce or augment HIV-1-specific delayed-type hypersensitivity (DTH) over a range of doses in asymptomatic HIV-1-seropositive adults. DESIGN: A single center, double-blind, adjuvant-controlled, dose-ranging trial involving 48 HIV-1-seropositive asymptomatic patients. Each dose group consisted of 12 subjects, eight receiving HIV-1 immunogen and four incomplete Freund's adjuvant (IFA). The doses studied were 50, 100, 200, or 400 micrograms (total protein). The HIV-1 immunogen was administered intramuscularly every 4 weeks for 36 weeks, with dosing contingent on the lack of an HIV-1 immunogen DTH response. A maximum of six doses was permitted. METHODS: Immunogenicity was assessed every 4 weeks by DTH skin testing to the inactivated HIV-1 antigen in saline with > 9 mm induration representing a response to immunization. Changes in p24-antibody levels were determined by endpoint titration using an enzyme-linked immunosorbent assay and Western blot. RESULTS: At doses of > or = 100 micrograms, all treated patients demonstrated significant differences in the ability to mount an HIV-1-specific cell-mediated response relative to adjuvant controls. Dose-related response patterns were observed in the period between doses and the occurrence of rises in HIV-1 DTH. Treatment appeared to increase p24-antibody titers as well as reactivities to other HIV-1 antigens as determined by Western blots. The HIV-1 immunogen was well tolerated. CONCLUSIONS: The minimum dose of the HIV-1 immunogen in IFA required to induce HIV-1 DTH relative to the IFA control group was 100 micrograms in this patient population.

Adult↗
PubMed1994

Serological tests for Lyme disease in patients with tropical spastic paraparesis and healthy Jamaicans.

The significance of reactive serological tests for Lyme disease in patients with tropical spastic paraparesis (TSP) was assessed by examining serum samples from 128 of these patients and 200 healthy Jamaicans by Lyme indirect immunofluorescent antibody (IFA), enzyme immuno-assay (EIA) and Western blot analyses. Sera were also examined in serological tests for syphilis (STS), an unabsorbed fluorescent treponemal antibody test and leptospira microagglutination test. The prevalence of positive Lyme IFA and EIA results did not differ significantly between sera from TSP patients (12.5%) and healthy controls (10.0%). Western blot analyses showed that the positive Lyme IFA and EIA results observed in this study were due to false positive reactions. Seventy-five per cent of Lyme IFA/EIS positive sera from TSP patients had treponemal antibodies. Eighty per cent of those from healthy controls were negative in standard STS but 85% were positive when tested in an unabsorbed fluorescent treponemal antibody (FTA). These data indicate that reactive serological tests for Lyme disease in Jamaican TSP patients and healthy Jamaicans are false positive reactions due to cross-reactivity with other spirochaetes, notably Treponema pallidum and non pathogenic treponemes.

Adolescent↗
PubMed1993

Antineutrophil cytoplasm antibodies in systemic polyarteritis nodosa with and without hepatitis B virus infection and Churg-Strauss syndrome--62 patients.

OBJECTIVE: Antibodies directed against components of neutrophil cytoplasm have been detected in various systemic vasculitides and especially in Wegener's granulomatosis. In polyarteritis nodosa (PAN) and Churg-Strauss syndrome, few data are available and correlation between clinical manifestations and antineutrophil cytoplasm antibodies (ANCA) has not been established. Therefore, we tested, before treatment of vasculitis, 62 consecutive patients suffering from PAN with hepatitis B virus (HBV) markers, PAN of unknown etiology or Churg-Strauss syndrome. METHODS: Only patients with PAN and Churg-Strauss syndrome were included in the study. The diseases were histologically and/or angiographically proven. Every patient's serum was tested by an indirect immunofluorescence assay (IFA) and, in 37 cases, by an enzyme linked immunosorbent assay (ELISA). RESULTS: ANCA detected by IFA were observed in 10.7% of the patients with PAN with HBV markers, in 27.3% of the patients with PAN without HBV markers and in 66.7% of the patients with Churg-Strauss syndrome. When ELISA was performed, 11.1% of the patients with PAN associated with HBV infection, 20% of the patients with PAN without HBV markers and 55.6% of the patients with Churg-Strauss syndrome were positive. ANCA were positively correlated with asthma and purpura and negatively correlated with HBV markers. CONCLUSION: Regardless of the technique used, Churg-Strauss syndrome was associated with ANCA in about 60% of the cases while, in PAN of unknown etiology, ANCA were found in about 25% of cases. In contrast, IFA and ELISA only detected ANCA in a limited number of cases of PAN related to HBV infection. ELISA positivity in patients with PAN and Churg-Strauss syndrome was usually associated with antimyeloperoxidase antibodies. In our cases of PAN, ANCA and purpura were significantly correlated, suggesting that, in these cases, small vessels are involved and therefore macroscopic and microscopic PAN coexist. Thus it seems that ANCA are essentially present in the cases of small vessel vasculitis, as has been described, and are not a marker of pure macroscopic PAN, at least at our present level of understanding of these antibodies.

Adult↗
PubMed1994

Comparison between immunofluorescence and enzyme-linked-immunosorbent assay in the determination of serum HHV-6 IgG.

546 human sera from healthy subjects, subjects with cytomegalovirus or Epstein-Barr virus infection and from cordal blood were tested for the human herpesvirus-6 (HHV-6) IgG content in an enzyme-linked immunosorbent assay (ELISA) to verify results previously obtained with an immunofluorescence assay (IFA). The HHV-6 isolate CV, obtained from a child with exanthem subitum, employed as antigen in both tests, belonged to HHV-6 variant B. The ELISA results were similar to those obtained with IFA. 445/546 (81.5%) sera had the same type of reactivity with the two serological procedures. To establish whether different HHV-6 strains may give different serological results, 117 out of the 546 sera tested with IFA against CV infected cells were also tested against cells infected with the HHV-6 isolate U1102 belonging to variant A. All the sera showed a similar reactivity.

Adolescent↗
PubMedDate not supplied

Asialo-positive cells are overexpressed whereas IL-2 induced LAK activity is impaired in mice hyperimmunized with an immunomodulating mycobacterial fraction.

Previously reported studies revealed that extensive immunization with the Methanol Extraction Residue (MER) of BCG tubercle bacillus in Incomplete Freund's Adjuvant (IFA) induced marked suppression of T and B cell functions and that immunosuppression was correlated with marked decrease in splenic T-cell population and marked increase in the splenic macrophage population. The purpose of the present work was to determine if extensive immunization with MER in IFA also induced changes in splenic asialo antigen positive (NK) population and in the potential of induction of splenic LAK activity in vitro by recombinant IL-2. By comparison with other test groups, namely mice injected with IFA only, injected once with MER in aqueous suspension and normal, untreated mice, hyperimmunization with MER resulted in marked increase in expression of asialo positive (NK) splenic cells whereas induction of splenic LAK activity by IL-2 was markedly depressed. Splenic macrophages originated from MER hyperimmunized mice had no effect on induction of LAK activity by IL-2 in a normal splenic population.

Animals↗
PubMed1994

Normal and abnormal torsional development in children.

This study presents findings in a series of 123 children with intoeing gait. The intoeing was caused by increased femoral anteversion (IFA) in 70% of the cases, and internal tibial torsion (ITT) in 30%. Rotation of the hips, thigh-foot angle, Q-angle, and computed tomography measured anteversion and tibial torsion divided the two groups very clearly. In the IFA group, 40.3% of the patients presented with an externally rotated tibia and 59.7% had an internally rotated tibia. In the ITT group, the anteversion was normal for age and the tibial torsion was significantly decreased. Eighty children who corrected their intoeing gait, and of whom 83.4% had IFA, were also reviewed: a decrease in anteversion was observed in 20.5% of the patients; 62.9% showed no decrease in anteversion.

Adolescent↗
PubMed1993

Western blot and indirect fluorescent antibody testing for antibodies reactive with Ehrlichia canis in sera from apparently healthy dogs in Zimbabwe.

Sera were collected from apparently healthy dogs in 3 major centres in Zimbabwe to establish the prevalence of antibodies reactive with Ehrlichia canis by indirect fluorescent antibody (IFA) testing at titres of 1/20 or greater. The overall seroprevalence was 42% (39/93) with dogs from Mutare (40%) and Harare (33%) having similar rates which were lower than those for Bulawayo (68%). The majority of the IFA positive dogs from Harare (67%) had no haematological or biochemical evidence of canine ehrlichiosis. Total protein, albumin and globulin values were determined in sera from blood collected from Bulawayo and Mutare and all values were within normal reference ranges. Western blot profiles of sera from dogs with IFA titres of greater than 1/160 were similar to those using sera from dogs experimentally infected with E. canis Oklahoma strain. Our results indicate that an organism which is antigenically very similar or identical to E. canis is present in Zimbabwe and that dogs are commonly exposed to this organism.

Animals↗
PubMed1993

Clinical and laboratory findings in chronic conjunctivitis in cats: 91 cases (1983-1991).

Clinical findings and laboratory test results from 91 cats with chronic conjunctivitis were studied to determine the causes of the disease and the sensitivity of diagnostic procedures used, and to identify correlations between results of various diagnostic procedures and clinical or signalment variations. Mean age of affected cats was 2.9 +/- 2.7 years (+/- SD), with a range from 1 month to 11 years. Conjunctivitis was more likely to be bilateral (56 cats) than unilateral (35 cats). In cats tested for FeLV or feline immunodeficiency virus infection, 15 and 8.5%, respectively, of the results were positive, compared with 4 and 2.6% for the general hospital population. Culturing or immunofluorescent assay (IFA) for feline herpesvirus 1 (FHV-1) and Chlamydia psittaci IFA resulted in identification of pathogens (positive test results) in 19% (FHV-1) and 18% (C psittaci) of tested cats. For FHV-1, culturing was more sensitive than was IFA, yielding positive results in 19 vs 8.8% of cases. In only 1 cat were FHV-1 and chlamydiae recovered. The probability of positive test results for FHV-1 or chlamydiae was unrelated to concurrent corneal disease, unilateral vs bilateral involvement, or age. Cause of conjunctivitis could not be definitively determined in the remaining 35 cases tested for both agents. Bacterial species considered to be potentially pathogenic were isolated from conjunctival sac specimens in only 1 of 38 attempts. Cytologic changes considered compatible with chlamydial or FHV-1 infection (intracytoplasmic inclusions or multinucleated epithelial cells, respectively) were found in 8 and 5 cases, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[Clinico-laboratory diagnosis of Lyme borreliosis--personal experience].

Between May 1992 and February (second half) 1993 two hundred patients with the history of tick bite have been examined at the Institute for Infectious and Tropical Diseases "Dr Kosta Todorović". Of the above 200 persons, 103 of them have had clinical/epidemiological evidence of Lyme disease (i.e. Erythema migrans). In order to establish the degree of seroconversion in this stage of Lyme disease, blood of each patient has been tested by PHA and IFA methods. Blood from each patient has been drawn in pairs, immediately before and after the treatment. By method of PHA we have analyzed 186 sera and found 23 positive results. By method of IFA we have analyzed 10 sera and found one positive result. By Comparative testing we have analyzed 10 sera, obtaining 5 positive results by PHA and 3 positive results ba IFA.

Adult↗
PubMed1993

Association between clinical lameness and Borrelia burgdorferi antibody in dairy cows.

Results of an ELISA, indirect fluorescent antibody (IFA) test, and immunoblot analysis (western blotting) for antibody to Borrelia burgdorferi in a sample of 216 lactating dairy cows were compared. The microscopic microtitration agglutination test for antibody to 6 serovars of Leptospira interrogans was also performed to evaluate possible cross-reactivity between B burgdorferi and L interrogans. Using western blotting as the standard test against which the ELISA and IFA test were compared, the ELISA had greater sensitivity (50% in summer and 38% in spring) with similar specificity (83 and 82%), compared with the IFA test (sensitivity, 6 and 5%; specificity, 90 and 83%). In addition, seropositivity to B burgdorferi, using the ELISA, was not found to be associated with seropositivity to L interrogans serovars. A matched case-control study evaluating the association between clinical lameness and antibody to B burgdorferi was performed in lactating dairy cows of 17 Minnesota and Wisconsin herds. Sera from case and control cows matched by herd, parity, and stage of lactation were evaluated, using an ELISA for B burgdorferi antibody during 2 seasons. High B burgdorferi antibody values were associated with clinical lameness in dairy cows (P = 0.006 in summer and P = 0.04 in spring).

Animals↗