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[Evaluation of the sensitivity of selected serological tests and activity of Coxiella burnetii antigens in the diagnosis of Q fever].

Sensitivity of three serological tests: indirect immunofluorescence assay (If), complement fixation test (CF), and microagglutination test (MA) was evaluated. Sera (118 samples) of humans suspected of C. burnetii infection were tested. Phase II antibodies were detected in 68.6% of sera and phase I antibodies--in 38.2% of sera. Among seropositive to phase II antigen--93.8% of sera reacted in IF, 62.9% in MA, and 32.1% in CF; among seropositive to phase I antigens--100% of samples reacted in IF, 2.6% in MA and 2.6% in CF. Calculated sensitivity of above tests was as followed: IF-93.8%, MA-67.1%, CF-34.2%. Some human sera (6.1%) reacted with hen egg antigens in CF. Reactivity of diagnostic antigens prepared from reference Henzerling strain and four others isolated in Poland with rabbit immune sera and sera of individuals suspected of C. burnetii infection in IF was compared. Generally, the immune sera reacted in highest titres with homologous antigens derived from homologous strains. Human sera showed differentiated activity to particular antigens. The titres of phase I antibodies fluctuated from 0 to 16 depending on the antigen applied. Because of that fact diagnostic antigens should be prepared from the mixture of reference strains and isolates from a region under study.

Agglutination Tests↗

Neutralization antibody to herpes simplex virus type 1 in Bell's palsy.

In 45 patients with Bell's palsy of recent onset, the neutralization antibody titers to herpes simplex virus type 1 (HSV-1) were assayed by a microtiter technique. As a control, the neutralization antibody titers of 50 normal subject were assayed. Complement fixation tests also were performed. The geometric means of the neutralization antibody titers of the patients appeared higher at all times than those of the normal subjects. Significant change in the neutralization antibody titer suggesting a recent infection of HSV-1 was seen in seven patients (15.6%), while the complement fixation test demonstrated significant change in only one patient (2.2%). The higher geometric means of the neutralization antibody titers in the patients was thought to indicate that reactivation of the HSV-1 infection was responsible for the onset of Bell's palsy.

Adolescent↗

Comparison of different serological methods for the determination of antibodies to Chlamydia psittaci in pigeon sera.

Several methods for detecting antibodies to Chlamydia psittaci using sera from pigeons were compared with regard to their sensitivity, specificity and efficacy. The reference method used was indirect immunofluorescence (IFI), which uses as antigen intracellular inclusions in McCoy cell monolayers. Indirect micro-immunofluorescence (MIF) using as antigen C. psittaci cultured on yolk sacs of embryonated eggs, direct and indirect complement fixation tests (CFT and ICFT, respectively), and enzyme-linked immunosorbent assay (ELISA) were compared to the reference method. Indirect micro-immunofluorescence proved to be the most efficient method, while ELISA was the most sensitive, though showing a very low specificity. No statistically significant difference was found in comparing the two complement fixation tests. The use of ICFT to check for the negative results obtained in CFT is questioned. Possible reasons for the different results with the methods used are discussed.

Animals↗

Toxoplasmic lymphadenitis--clinical and serologic profile.

OBJECTIVE: To study the serologic profile of several types of test for toxoplasmosis, in order to contribute to the interpretation of antibody kinetics. METHODS: The clinical and serologic features of 120 cases of lymphadenopathy with known time of clinical onset were studied during 18 months postinfection. Antibody kinetics was determined by Sabin-Feldman dye test, complement fixation with light antigen, IgM immunofluorescent antibody test, and IgM immunosorbent agglutination assay (IgM-ISAGA). Cell-mediated immunity was evaluated by the toxoplasmin skin test. RESULTS: Seventy-five female patients aged 11-54 years (median 27 years) and 45 male patients aged 3-59 years (median 17 years) were studied, 85% of whom were under 30 years of age. Cervical lymph nodes were involved throughout, generally on both sides, with more than one affected ganglion group in 88%. The predominant symptom was asthenia (69%), which persisted in some cases for several months. A negative Sabin-Feldman dye test in a lymphadenopathy with more than three weeks' evolution excludes a toxoplasma etiology. A positive Sabin-Feldman dye test with negative IgM-ISAGA almost invariably excludes recent infection. The Sabin-Feldman dye test was positive in 94% of patients with titers higher than 1 : 16 000 within the first three months. The IgM-ISAGA yielded 98% of positive results, of which 94% were high titers. Titers >/= 1 : 160 in the IgM immunofluorescent antibody test and complement fixation were found to be highly indicative of recent infection, since 87% and 91%, respectively, were found within the first three months. A negative skin test plus positive serology values indicates recent infection. CONCLUSION: Our results indicate that estimation of time of infection on the basis of serologic results is improved by the simultaneous application of several tests, and correlates closely with the presence of clinical lymphadenitis.

Adolescent↗

Suppression of naturally occurring anti-tissue antibodies during growth and after removal of tumours.

The sera of normal rats were found to be active in the complement fixation test against isogeneic tumour homogenates. This activity was shown to be heat labile and to sediment with IgM globulins on zone ultracentrifugation in sucrose density gradients. Sera from rats bearing progressively growing tumours and sera from rats, which had such tumours excised, were found to be less active than normal rat sera in the complement fixation test against isogeneic tumour and liver homogenates. It was considered that this suppression of naturally occurring anti-tissue antibodies may be a specific process related to the host immune response to the tumour.

Animals↗

Standardization of serological tests for detecting anti-Trypanosoma cruzi antibodies in dogs.

This paper reports on the standardization of four serological reactions currently used in human serodiagnosis for the detection of anti-Trypanosoma cruzi antibodies in naturally and experimentally infected dogs. Indirect immunofluorescence test (IFAT) and hemagglutination test (IHAT) were standardized, and complement fixation test (CFT) and direct agglutination test (DAT) were used for diagnostic confirmation. Four hundred and eighty one mongrel dogs that were studied by xenodiagnosis were used: (1) parasitemic dogs of two localities of endemic area (EA) of Santiago del Estero province in Argentina (n = 134); (2) non-parasitemic dogs of the same area (n = 285); (3) dogs experimentally infected with T. cruzi in the patent period (n = 6); (4) non-infected dogs (n = 56) which were born in the city of Buenos Aires (BA), one non-EA for Chagas' disease. For IFAT, parasitemic dogs EA showed 95% of reactive sera. Non parasitemic dogs EA showed 77% of non reactive sera. None sera from BA were reactive for dilutions higher than four. For IHAT, 84% of sera of parasitemic dogs EA showed serological reactivity and among non parasitemic dogs BA, 61% were non reactive, while the remainder showed at most titres of 1/16. The cut-off titres for IFAT and IHAT were 1/16 and 1/32 respectively, and for CFT and DAT 1/1 and 1/128 respectively. Sensitivity for IFAT, IHAT, CF and DAT were 95%, 84%, 97% and 95% respectively.

Agglutination Tests↗

[Inhibition of platelet migration. A simple technic for typing of PLA1 and the detection of platelet allo- and autoantibodies].

In vitro, platelets can migrate in an active way. This migration can be immunologically inhibited through specific antibodies. This test (PMI-test) can be easily carried out in any laboratory. In that study this test was used: 1) For the detection of anti-platelet allo-antibodies in neonatal thrombopenia. Out of nine cases studied, two anti-PLA1 were identified and three anti-HLA antibodies (anti-B8, anti-B17+21 and a polyspecific serum) detected thanks to the micro-lymphocyto-toxicity test were confirmed by that test. 2) To find free auto-antibodies in the sera of patients suffering from idiopathic thrombopenic purpura. In five cases out of twelve the presence of auto-antibodies could be shown, that is 41,6%. In some cases, the auto-antibodies showed a certain degree of specificity as it had already been pointed out in other studies. When the thrombopenias were associated with other diseases, all the tests were negative. 3) For the PLA1 typing of donors: 1,85% donors submitted to the test proved to be PLA1 negative. 4) To identify anti-HLA antibodies and to compare this test with the micro-lymphocyto-toxicity-test: the anti-A2, A11, B8, B17, CW3 and CW4 antibodies used titrated the same in both tests. 5) Eventually to study the possible action of ABO-system antibodies in this test; this study shows that only sera containing immune antibodies can bring about an inhibition of the incompatible platelet migration. The sensitivity of the PMI-test which has previously been mentioned as equal to platelet-lysis and superior to aggregometry and platelet factor-3 release, is superior to the complement fixation test since with an 1/16 titre in PMI test for the two anti-PLA1 antibodies, the latter could not be detected through the complement fixation test; it seems to be equal to platelet indirect radioactive Coombs since both sera titrate in the same way.

ABO Blood-Group System↗

Cellular and humoral immune responses to herpes simplex virus during and after primary gingivostomatitis.

A total of 17 children, aged 1 to 15 years, with gingivostomatitis were investigated to follow the development of immune parameters in those who suffered from herpes simplex virus stomatitis. Mouth swabs were obtained during the acute attack. Blood samples were collected on this occasion and again about 3 weeks later. Humoral immunity to herpes simplex virus was investigated by a complement fixation test and by an antibody-dependent cell-mediated cytotoxicity test. Cell-mediated immunity was investigated in a blast transformation assay with herpes simplex virus type 1 antigen and phytohemagglutinin. Interferon production in herpes-stimulated cultures was measured. Thirteen patients had a herpes simplex stomatitis. Twelve of these children were negative in the complement fixation test on the first serum specimen, but only five were negative in the antibody-dependent cell-mediated cytotoxicity test. These five were still febrile at the time of investigation. Blast transformation was negative at the first investigation in most children, whereas interferon was produced both in leukocyte cultures obtained during the infection and also in cultures made 3 to 4 weeks after the infection. An increase in immune parameters was seen in all patients with herpes stomatitis. From results in blast transformation and antibody-dependent cell-mediated cytotoxicity, it is seen that cell-mediated and humoral immunity can be found at the same time during recovery from this type of infection.

Adolescent↗

Cross-reactions between protamines of different species: the role of arginine clusters.

Human and monkey sera containing autoantibodies to protamines reveal often strong cross-reactions with protamines of other species including salmon protamine. These cross-reactions can be readily detected both in the immunofluorescence test and th micro-complement fixation test. These sera react to a much lesser extent with poly-L-arginine. The results indicate that the cross-reactions of these protamines are not primarily due to clusters of arginine.

Animals↗

The double diffusion precipitin test in human fascioliasis.

The recent outbreaks of human fascioliasis in Britain provided the opportunity for employing the double diffusion precipitin test in the diagnosis of this disease. In sensitivity and specificity this test appears to equal the complement-fixation test and has the advantages of simplicity and speed in its performance.

Antigens↗

Isolation of Toxoplasma gondii from goats with history of reproductive disorders and the prevalence of Toxoplasma and chlamydial antibodies.

The prevalence of antibodies to Toxoplasma gondii and Chlamydia psittaci was assessed in goats with a history of abortion, stillbirth and neonatal mortality. Antibodies were detected in 540 (30%) and 57 (3.2%) goats out of 1799 tested by indirect haemagglutination and complement fixation tests, respectively. Toxoplasma gondii was isolated for the first time in Botswana from 22 out of 81 sets (27.2%) of foetal tissues, maternal and foetal cotyledons and uterine tissues of goats which had previously aborted or given birth to stillborn or weak kids that died within two days of birth. These results implicate T. gondii and C. psittaci, but especially the former, to be associated with caprine reproductive problems and require appropriate control measures.

Abortion, Veterinary↗

Broad reacting surface antigens in Leptospira biflexa serovar andamana.

Previous investigations had demonstrated that genus-specific and species-specific antigens of leptospires are deep-seated within the leptospiral cell. Conversely, the present study has shown that strain CH11, serovar andamana of the non-pathogenic species of Leptospira biflexa is endowed on its surface with two cross-reacting antigens; a newly recognized antigen common to L. interrogans and L. biflexa spp. and an antigenic determinant common to a previously described genus-specific protein antigen (GP-Ag). The serovar andamana, when thimerosal-treated, behaved like an interspecies-specific antigen, cross-reacting in the complement fixation test with sera from rabbits immunized with L. interrogans and L. biflexa spp. and with sera from subjects with leptospirosis from various serovars. In the immuno electron microscopic test, human leptospirotic sera bound to the surface of thimerosal-treated andamana and not to the surface of untreated andamana showing that an interspecies-specific antigen was located underneath the outermost layer of this serovar. In the same test, the monoclonal antibody GP-7 against the GP-Ag bound to the surface of untreated andamana and not to the surface of thimerosal-treated andamana, showing that an antigenic determinant, common to GP-Ag and different from the first one, was located on the outer membrane of andamana. In human leptospirotic sera, antibodies against the cross-reacting antigen of thimerosal-treated andamana demonstrated by the complement fixation test were formed earlier and in a higher percentage of sera than the serovar-specific antibodies against 16 L. interrogans serovars demonstrated by the microagglutination test.

Agglutination Tests↗

[Standardization of in-vitro methods for diagnosing allergic disorders].

The various "in vitro" techniques were studied and the conclusion was reached that the hemagglutination and complement fixation tests were the most suitable for diagnosis. Sera were selected from 377 patients with very positive intracutaneous reactions to the antigens in question, the distribution being as follows: 110 sera positive to milk, 114 sera positive to eggs, 95 sera with a very marked intracutaneous reaction with gramineous pollen, and 58 with house dust. By means of the hemagglutionation technique of Boyden and the complement fixation test of Kolmer with these antigens, it was determined that the diagnostic reliability for food substances was 94,4% in the sera with positive anamnesis. For milk, there was 100% reliability in bronchial asthma and atopic dermatitis. With respect to pollen, hemagglutination gave 100% reliability in patients with positive anamnesis. The percentage with complement fixation was somewhat lower. Comparing the diagnostic reliability with hemagglutination, house dust gave an arithmetic average of 82,6% in positive anamnesis. With these antigens, hemagglutination by Boyden's technique appears the most suitable method.

Animals↗

Comparison of the results of some serological tests for bovine brucellosis.

A total of 1887 bovine sera positive to the Rose Bengal plate test were subjected to other serological tests for bovine brucellosis: the complement fixation test using warm fixation (CFTW),the serum agglutination test (SAT) and the radioimmunoassay (RIA). The SAT was generally much less sensitive than the CFTW. Many sera, however, gave positive reactions in the SAT but no reaction in the CFTW or the RIA. These SAT reactions were attributed to IgM antibody. Comparison between the results of the CFTW and the RIA led to the conclusion that 200 ng could be used as a minimum diagnostic reaction in the RIA.

Agglutination Tests↗

An evaluation of serologic tests used to diagnose brucellosis in buffaloes (Bubalus bubalis).

Five serologic procedures were evaluated in buffaloes and results compared with cultures of 64 udder secretion specimens. The rivanol test was superior to all other methods in specificity. The card, rivanol and complement fixation tests identified all infected cows. Many sera had complement fixing antibodies while agglutinins were absent. It was concluded that these were false positive results. A new procedure, the particle concentration fluorescence immunoassay, was a sensitive screening test but lacked specificity. On a limited number of samples, the tube agglutination test lacked sensitivity and was not a very useful procedure for the diagnosis of brucellosis. All 18 isolates of Brucella abortus were biovar 1.

Agglutination Tests↗

Antibody development in pigs inoculated with live or killed cultures of Brucella abortus.

As shown by density gradient ultracentrifugation and column chromatography, pigs formed IgM antibodies during the first week following vaccination with Brucella abortus, strain 19. At this time their sera reacted in both plate and tube agglutination but not in complement-fixation tests. A few days later, when IgG antibodies had developed, agglutination titers were still high and some activity was recorded in hemolytic complement-fixation tests. A similar sequence was observed in pigs repeatedly inoculated with phenol-killed suspensions of B. abortus. As the proportion of IgM to IgG antibodies decreased, agglutinin titers fell in relation to complement-fixing titers. In some animals the conglutinating complement absorption test became positive earlier than the plate agglutination.

Agglutination Tests↗

[Toxoplasmosis and contact with animals: study of 390 cases].

Three hundred and ninety patients with suspected toxoplasmosis due to their contact with animales--they owned them, or work with them--are studied. The great significance of this way of acquiring the disease is stated. Every patient had a complement fixation test and an intradermal reaction test with toxoplasmine. An 85.2% positiveness to complement fixation, and a 64.1% to intradermal test were found among those patients who informed animal contact; a 70,6% positiveness to complement fixation, and a 56,2% to intradermal reaction was found in the patients who denied having any contact with animals. This showed both the importance of animal contact as well as other forms of transmission. The contacts were also studied, and the animals were classified according to J. Jira, the researcher: maximal, high, minimal and unreceptiveness to toxoplasma. The possibility of acquiring toxoplasmosis from other sources besides the close contact with animals must be taken into consideration.

Animals↗

A comparative study of ELISA and other methods for the detection of Brucella antibodies in bovine sera.

Enzyme-linked immunosorbent assay (ELISA), using beta-galactosidase and a fluorigenic substrate, was used for the detection of antibodies to Brucella abortus in bovine sera. Among 677 animals from 9 brucellosis-free herds, none reacted in the ELISA. Among 785 animals from 23 brucellosis-infected herds, 336 were positive in ELISA, 229 in the slow agglutination test (SAT), 185 in the complement fixation test (CFT), and 165 in the Rose-Bengal test (RBT). Experimental infections were conducted with two B. abortus strains. Al slaughter on day 101, after intraconjunctival infection of heifers with B. abortus strain 19 organisms, 3 animals were positive in the SAT, 3 in the CFT, 4 in the RBT and 11 in the ELISA, and Brucella organisms could be cultivated from 10 animals; among these, 2 scored positive in the SAT, 3 in the CFT, 3 in the RBT and 8 in the ELISA test. Seventeen heifers were infected with organisms of B. abortus strain 2308. On day 101, 11 heifers were found to be carriers, all of which yielded positive results in the CFT, RBT and ELISA tests, but not in the SAT.

Agglutination Tests↗