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[Aspects related to the antigenic structure and serological specificity of brucellae phylogenetically related to S- and R-forms and dissociated into R-variants].

The antigenic structures and serological properties of Brucellae S- and R-forms, phylogenetically differentiated, and dissociated R-variants are studied by means of gel-precipitation, immunoelectrophoresis and fixation of the complement. The Brucella suis 1330S, Brucella suis 1330R, Brucella ovis 02 and Brucella abortus 99 are involved in the experiments. Both specific and general antigenic structures are established in all strains studied, but only homologous antibodies from the antigen-antibody complex in the complement-fixation test, induced by the phylogenetically differentiated S- and R-forms (Brucella ovis) or brucellae, diverged into R-variants. Cross complement-fixation tests between the antisera, prepared against S-forms and antigens from natural R-forms (Brucella ovis) or dissociative R-forms (R-variants) have not been observed. Also cross reactions between antisera, induced by R-forms (natural R-forms--Brucella ovis, or dissociative R-variants) and antigens, obtained from S-forms of brucellae are found.

Antigen-Antibody Complex↗

Pityriasis rosea. Viral complement fixation studies.

Eleven patients were seen for pityriasis rosea and underwent acute and convalescent viral complement fixation tests for several respiratory viruses and Mycoplasma. Several patients (6/11) gave a history of antecedent upper respiratory illness; however, no significant rise in titer was seen on any of the complement fixation tests.

Adolescent↗

Comparative evaluation of a field-based dot-ELISA kit with three other serological tests for the detection of Brucella antibodies in goats.

A dot-ELISA (d-ELISA) test was evaluated and compared with the serum agglutination test (SAT), micro-complement fixation test (CFT) and a plate-ELISA (p-ELISA) for field use in screening herds of goats against brucellosis. During the standardization of the dot-ELISA kit on 1732 caprine serum samples, 1571 samples out of 1666 were found to be negative in d-ELISA, SAT and micro-CFT, while 59 were positive in different combinations. Of a further 66 serum samples, 34 were negative and 31 were positive in different combinations in d-ELISA, SAT, micro-CFT and p-ELISA. A total of 1584 goats belonging to different herds were then screened for brucellosis. Of the 694 serum samples screened in the first batch using d-ELISA, a positive reaction was observed in 26 cases. Further screening of these cases revealed 13 and 21 goats as positive reactors in SAT and CFT, respectively. In a second batch of 890 goats there were 109 positive reactors in d-ELISA. Among these 109 goats, 34, 40 and 80 goats were positive reactors in SAT, CFT and p-ELISA, respectively. The results of d-ELISA correlated well with those of p-ELISA. Dot-ELISA was found to be a more suitable and rapid test for screening large numbers of goats in the field.

Agglutination Tests↗

Serological reactions to Brucella species in British pigs.

Until and including 1987 diagnostically significant serological titres to swine brucellosis had occurred in the serum agglutination test (SAT) or the complement fixation test (CFT), ie, > or = 100 iu or > or = 20 icftu, respectively, almost every year since reliable records began, but usually only about 0.05 per cent in the SAT and 0.005 per cent in the CFT. Brucella suis was never isolated by cultural examination. In 1988 the level of CFT reactions > or = 20 icftu rose to 0.42 per cent (1.04 per cent in the last quarter of the year) but the SAT reactions remained relatively unchanged. In 1989 the levels of both CFT and SAT reactions increased further with CFT reactions again predominating. Analyses of the serological reaction patterns in individual herds suggested that infection with brucella or some other organism capable of causing serological cross-reactions had become widespread in Great Britain, although signs of disease typical of swine brucellosis had not been observed. Some herds had reactions which persisted for many months whereas others showed them for only a short time. In early 1990 Yersinia enterocolitica serogroup O:9 was isolated from some pigs purchased from one of the reactor herds and this organism is probably responsible for the increased numbers of seroreactions. It had not previously been found in pigs in Great Britain.

Agglutination Tests↗

Rangiferine brucellosis on Baffin Island.

The standard tube agglutination test (STAT) and the complement fixation test (CFT) were used to assess the seroprevalence of antibodies to Brucella spp. in caribou (Rangifer tarandus) from three populations on Baffin Island, Canada. During late winter from 1983 to 1986, sera from 17 of 40 North Baffin (43%), 11 of 33 Northeast Baffin (33%) and 12 of 82 South Baffin (15%) adult caribou had antibodies in the STAT at 1:50 or the CFT at 1:5. Seroprevalence increased as caribou matured with one (4%) of 25 calves, four (13%) of 31 yearlings, and 40 (26%) of 155 adult caribou being positive. However, seroprevalence did not differ with sex in any age class. Positive antibody titers were higher in adult females sampled in May, 3 to 4 wk before parturition, than in adult females sampled in late March and April. The strength of positive titers did not differ with the time of sampling among adult males. Pathologic signs of brucellosis were found in three (13%) of 23 caribou that were assumed to have active infections (caribou with CFT titers > 1:160). Brucella suis biovar 4 was isolated from 24 (60%) of 40 caribou from which lesions were submitted. Between 1986 and 1990, the annual incidence of reported human (Homo sapiens) cases averaged 3.4 (34:100,000) on Baffin Island.

Age Distribution↗

[A modified immunofluorescence test to demonstrate toxoplasma antibodies (author's transl)].

A modified test to demonstrate toxoplasma antibodies by immunofluorescence is described in detail. This test was used in more than 16 000 cases. The antibody content of a patient's serum is assessed from a single dilution of 1:4 by two criteria: 1. The number of toxoplasms in the assay is kept constant. The percentage of antibody loaded cells varies with the concentration of antibodies in the patient's serum. 2. The intensity of fluorescence is correlated to the antibody content of the serum and the latter can be determined by means of standard sera. The results of this method are expressed in degrees of brightness. We compared three different methods and found an identical behaviour of the FATOX III and the Sabin-Feldman test. Between the complement-fixation test and the FATOX III there is the same relation as between JFT and SFT. This is shown in tables presenting the results for 1621 sera. The method is described in detail.

Antibodies↗

Evaluation of an enzyme-labeled antiglobulin test for anti-Brucella immunoglobulin G among 3 cattle populations.

Antibody to smooth Brucella abortus lipopolysaccharide antigen on the surface of polystyrene tubes was detected with peroxidase-labeled antibody against bovine immunoglobulin G. The enzyme-labeled antiglobulin test (ELAT) activity of samples was expressed in arbitrary units/0.01 ml by reference to a standard curve based on tests of dilutions of a positive serum pool. Reactions greater than 3.0 U/0.01 ml were classified positive because specificity at this level was 99.8% (417/418 samples correctly classified negative) with agglutination test-negative sera from 33 Brucella-free herds. Results of the ELAT were compared with results of agglutination tests and the complement-fixation test (CFT), using 430 sera from cattle in 7 infected herds. Activity of greater than 5.0 ELAT U/0.01 ml was detected in all 54 sera classified as positive (titer greater than 1:10) by the CFT, including 5 sera classified as negative by the tube agglutination test. Sera from 8 nonvaccinated cows in the infected herds reacted only by the ELAT, whereas reactions were obtained with 25 and 5 sera by only agglutination tests and the CFT, respectively. The ELAT and CFT results were in agreement for 25 of 26 sera from agglutination test-reactor cattle in herds of unknown status. Comparisons of milk ring and whey agglutination tests with the whey ELAT on 146 quarter samples from cows in an infected herd revealed no ELAT activity greater than or equal to 1.0 U/0.01 ml in the 73 samples considered negative by the 2 other tests. Samples (n = 47) that contained greater than or equal to 1.0 ELAT U/0.01 ml included all (n = 40) samples with milk ring or whey agglutination titers greater than or equal to 1:16 and greater than or equal to 32, respectively, and 7 samples that gave weaker reactions to the latter tests.

Agglutination Tests↗

Determination of patient herpes simplex virus immune status by latex agglutination.

A rapid latex agglutination (LA) test was compared with complement fixation and enzyme immunoassay for the determination of herpes simplex virus immune status in sera of patients. Of 173 samples, 88% gave concordant results in all three assays (115 positive and 37 negative). The LA and complement fixation tests agreed 92% of the time, and the LA agreed with the enzyme immunoassay 94% of the time. LA is a simple and rapid test which can be used for determining the herpes simplex virus immune status in sera of patients.

Antibodies, Viral↗

Antibodies in histoplasmosis.

Production of precipitating and complement-fixing antibody in rabbits and other animals was induced by immunization with live yeast-phase cells of Histoplasma capsulatum. Results of studies of polysaccharide antigens from three strains of H. capsulatum, by quantitative complement-fixation with human and rabbit antisera, strongly suggest the presence of type specificity. The variations of titer during 11 weeks in one patient with histoplasmosis and the variations of titer among a group of patients with histoplasmosis were studied by use of quantitative complement-fixation tests.

Animals↗

Brucellosis serology: reduced dose S19 vaccination of yearling heifers versus the use of the standard dose at 5-7 months of age in a clean herd.

In the 427 heifers vaccinated at 12 to 14 months of age with the reduced dose (3 X 10(8) to 1 X 10(9) viable organisms per dose) 3 had antibody titres in the complement fixation test of 196, 688 and 748 IU ml-1, respectively, at 5 months post-inoculation. At 23 to 25 months of age 8/128 (6.3%) of these heifers had rose bengal test (RBT) reactions, at least 6/128 (4.7%) a serum agglutination test (SAT) antibody titre in excess of 30 IU ml-1 and 1/128 had a suspicious reaction in the complement fixation test (CFT) of 30 to 49 IU ml-1. In the 116 heifers inoculated with the standard dose (4 to 12 X 10(10) viable organisms) at 5 to 7 months of age and tested at 22 to 24 months of age, a reactor rate of 37/116 (31.9%) in the RBT was seen. At least 34/116 (29.3%) had antibody titres in excess of 30 IU ml-1 in the SAT. Only 1 animal had a suspicious reaction in the CFT of 18 to 24 IU ml-1. No abortions could be attributed to the vaccine strain and no other isolates of the vaccine strain were made. The possible role of vaccine residues in syringes as a cause of persistent reactions is discussed. The use of disposable syringes is recommended. On serological grounds there appears to be little advantage in using the reduced dose vaccine in yearling heifers as opposed to the standard dose vaccination of 5 to 7 month old heifers.

Age Factors↗

Brucellosis of camels in Kuwait.

This study investigated the presence of Brucella antibodies in serum and milk obtained from camels in Kuwait. Brucella strains were also isolated from the foetus using standard technique (Webridge Lab Techniques). Three serological tests for serum were adopted. These tests were Rose Bengal Plate Test (RBPT), the Serum Tube Agglutination Test (SAT) and the Complement Fixation Test (CFT). The RBPT was used for all sera samples, and both SAT and CET were used for the positive RBPT. Camels that showed a titer of 1:40 in SAT or 1:5 in CFT or greater were considered positive. Thirteen of the samples examined were found positive by CFT (at 1:5); by SAT, they showed a titer of 1:20. One serological test, the Milk Ring Test (MRT), was used for milk. Here 3 and 2 were considered positive reactors but 1+ was considered suspicious. We were unable to isolate the Brucella organism from Sedemine and Cream of milk, but we isolated them from Foetus Brucella abortus and it is confirmed by Webridge Laboratory, U.K. It is Brucella abortus (Biovar 1). The prevalence rate was 14.8% from serum by the CFT and RBPT methods and 10.8% by the SAT method. For milk, the prevalence rate was 8.0%. Two Brucella abortus were isolated from 5 foetuses.

Agglutination Tests↗

Validation of the fluorescence polarization assay and comparison to other serological assays for the detection of serum antibodies to Brucella abortus in bison.

A number of serological tests were compared for the detection of antibodies to Brucella abortus in bison (Bison bison). The performance of the fluorescence polarization assay (FPA) in both the preliminary evaluation and a subsequent blind validation indicated that this test was the most suitable for serological diagnosis of brucellosis in bison. The sensitivity and specificity in the preliminary evaluation were 92.1% and 99.4%, respectively. The sensitivity and specificity in a subsequent blind study were 96.3% and 97.6%, respectively. In a double blind study conducted on bison vaccinated with B. abortus strain 19, the data suggests that the FPA can differentiate bison infected with B. abortus from bison vaccinated with B. abortus strain 19. Both the indirect immunoassay (IELISA) and the competitive immunoassay (CELISA) performed nearly as well as the FPA. The buffered antigen plate agglutination test (BPAT) and the complement fixation test (CFT) did not perform as well as the FPA, CELISA or the IELISA in both studies. The FPA is a homogeneous assay eliminating the washing steps and reducing incubation to minutes rather than hours saving on time, equipment, materials, reagents and cost. These attributes, together, with its excellent sensitivity and specificity make the FPA an attractive test for the detection of serum antibodies to Brucella abortus in bison.

Agglutination Tests↗

Lymphogranuloma venereum. Outbreak in a university community.

One aspect of the current epidemic of venereal diseases is the spread of lymphogranuloma venereum (LGV). Formerly confined to the lower echelons of society, it now affects more affluent classes as well. A cluster of four cases was seen in a small college town. Serial LGV complement fixation tests, the most valuable diagnostic tool, may reveal many more cases than reported previously. Early treatment is important. We recommend therapy for all persons sexually exposed to LGV who have any LGV complement fixation test anomaly, whether or not clinical signs develop.

Adult↗

Immuno-dot blot as a rapid diagnostic method for detection of chlamydial infection in koalas (Phasolarctos cinereus).

The sensitivity and specificity of an immunoscreening test for anti-chlamydial antibodies in koala (Phasolarctos cinereus) serum were determined after the adsorption of non-specific antibodies. The results of the test were compared with complement fixation tests, tissue culture, gene probe analysis and dot blot immunoscreening for host-borne chlamydial antigen. The immunoscreening test was the most sensitive test for the identification of chlamydial infection in koala serum samples, furthermore it was rapid, taking approximately 16 hours to complete, and inexpensive. However, for the assay of swab material from koalas, gene probe analysis remains the most sensitive method of detection of chlamydiae.

Animals↗

An investigation of the Mycoplasma pneumoniae infections in Cambridge in 1983 using mu-capture enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence (IF) and complement fixation (CF) tests.

The mu-capture, the ELISA, IF and CF tests were used to study Mycoplasma pneumoniae infections in Cambridge in 1983. We studied 393 samples of serum submitted for investigation of M. pneumoniae infection, from 298 patients. There was a good correlation between mu-capture ELISA and IF for detecting M. pneumoniae-specific IgM, and between elevated CF titer, and the presence of M. pneumoniae-specific IgM. There was also a clear correlation between M. pneumoniae-specific IgM status and age. M. pneumoniae-specific IgM and IgA were most often found together in sera, but in some sera, only one of these antibodies was found at significant levels. These findings were not age related, and thus not obviously useful in differentiating primary and recurrent M. pneumoniae infections.

Adolescent↗

Antigenicity of bdellovibrios.

Antigenic relationships between 12 locally isolated bdellovibrios and 3 established reference strains (109D, 6-5-S, and UKi2) were investigated. Antigenicity of the strains was examined by use of the micro-complement fixation test, the serum and complement bactericidal test, and the immunodiffusion test. Antisera were prepared against one of the local strains (MS7) and against one of the established reference strains (UKi2). The complement fixation titers suggest a close relationship among all strains. Immunodiffusion tests produced lines of identity between the homologous strain MS7 and all other strains. It is suggested on the basis of these results that bdellovibrio may possess a common antigen.

Antigens, Bacterial↗