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PubMed1983

The complement fixation test for the diagnosis of Brucella ovis infection in rams--an Animal Health Division Report.

Complement fixation tests using three B. ovis antigen preparations in warm fixation tests (WCFT) and cold fixation (CCFT) tests were done on 541 ram sera. Semen samples from the same rams were examined culturally to identify B. ovis excretors. The CCFT, using an antigen prepared by heat extraction of B. ovis cells, had a sensitivity of 97% in 124 rams which were shedding B.ovis. The specificity was 99% in 144 rams from non-infected flocks. Seventy-seven per cent of 156 rams which reacted to this test were shedding B. ovis in their semen. Tests with other antigens were inferior in sensitivity and/or specificity. The WCFT gave lower titres than CCFT. Vaccination caused large numbers of false positive reactions in 4 flocks.

Journal Article↗
PubMed1985

The use of a single complement fixation test technique in bovine brucellosis, Johne's disease, dourine, equine piroplasmosis and Q fever serology.

The same techniques may be used in the complement fixation test (CFT) for the serological diagnosis of bovine brucellosis, Johne's disease (paratuberculosis), dourine, equine piroplasmosis and Q fever (caused by Coxiella burnetii). The reproducibility of results is excellent, falling for the most part within the twofold range and never exceeding the fourfold range. Agreement with other laboratories is excellent (i.e. within twofold) in the case of brucellosis and equine piroplasmosis antibody titres. A good correlation between the occurrence of the disease and serological reactions is found on circumstantial evidence in the cases of dourine, Johne's disease and Q fever. A standard unitage system is used to report the antibody titres found in all the tests. To simplify laboratory protocols, laboratories required to employ the CFT for the diagnosis of these diseases are advised to use a single proven technique in all the tests. Problems experienced with transient false-positive Johne's disease antibody titres in cattle following on tuberculin (bovine and avian) testing make it advisable to take specimens for the Johne's disease test prior to performing the tuberculin tests.

Animals↗
PubMed1984

Preparation, assessment and preservation of antigen from Brucella abortus strain 45/20 for use in the rough antigen complement fixation test.

Two methods of extraction were used to prepare antigens from Brucella abortus rough strain 45/20. The antigens were assessed for use in the complement fixation test. A suitable antigen was prepared using the saline extraction method of Miller et al. (1976) and used extensively in CF tests. Four methods of preservation were compared; -20 degrees C, -196 degrees C, 0.5% phenol at 4 degrees C, and lyophilisation. The antigen could be stored at -20 degrees C or -196 degrees C for up to 2 years.

Animals↗
PubMed1996

Serological diagnosis of ovine enzootic abortion by comparative inclusion immunofluorescence assay, recombinant lipopolysaccharide enzyme-linked immunosorbent assay, and complement fixation test.

Since the 1950s, serological diagnosis of ovine enzootic abortion (OEA), caused by strains of Chlamydia psittaci, has been based mainly on the complement fixation test (CFT), which is neither particularly sensitive nor specific since antibodies to other chlamydial and enterobacterial pathogens may be detected. In this study. a recombinant enzyme-linked immunosorbent assay (rELISA) (medac, Hamburg, Germany), based on a unique chlamydial genus-specific epitope of Chlamydia trachomatis L2 lipopolysaccharide, was evaluated for sensitivity and specificity as a primary screening assay for OEA by comparison with the CFT. A comparative inclusion immunofluorescence assay (IFA), in which antibody titers to C. psittaci and Chlamydia pecorum were examined, was used as the reference test for 573 serum samples from four flocks. Reactivity to C. pecorum was measured since inapparent intestinal infections by C. pecorum are believed to be common in British flocks. In detecting positive sera from an abortion-affected flock, in which a C. pecorum infection was also suggested by IFA, the rELISA outperformed the CFT with significant evidence for increased sensitivity (P = 0.003). In two flocks in which C. pecorum infections alone were suggested by IFA, the rELISA and CFT were prone to detect low levels of false-positive results, but the values were not significant. The rELISA provided results in one flock in which sera that were anticomplementary could not be resolved by the CFT. In another flock in which abortion had not occurred but infection by both chlamydial species was suspected, no significant difference was found between the sensitivities of the rELISA and CFT. The rELISA could not differentiate ovine C. psittaci and C. pecorum infections but was shown to be a more sensitive primary screening test for OEA than was the CFT, particularly where abortion had occurred and even when antibodies due to additional inapparent infection(s) by C. pecorum were present.

Abortion, Veterinary↗
PubMed1988

Application of the single radial complement fixation test for serodiagnosis of influenza, respiratory syncytial, mumps, adeno type 3, and herpes simplex type 1 virus infections.

A stabilized modification of the single radial complement fixation (SRCF) test in gel was developed for detecting various virus antibodies. The principle of the test is based on the use of a single-stage procedure with an agarose plate containing virus antigens and antibody-coated erythrocytes, and thin plastic film coated with complement. By filling the wells in the agar plate with a 1:4 diluted heat-inactivated sera and covering the agar surface with a complement film, a zone of unlysed cells surrounded by a hemolytic area appears after incubation overnight at 4 degrees C and then for 1-2 h at 37 degrees C, depending on the antibody titers. The SRCF antibody titer is calculated numerically from the square of the diameter of the unlysed cell zone. The stability of reagents could be significantly improved using thin complement film and several stabilizers. When this test was used for serodiagnosis of influenza, respiratory syncytial (RS), mumps, adeno virus type 3 and herpes simplex type 1 virus infections (using a total of 400 sera), excellent correlations were demonstrated for antibody titers between conventional complement fixation (CF) and SRCF titers. Furthermore, the expression of antibody titer as an SRCF unit with consecutive value, produced results sensitive to fluctuations in the antibody titers. The simplicity of the procedure, stability of the reagents, and excellent correlation with the conventional CF test might make this a useful test for routine serodiagnosis and seroepidemiological survey of various virus infections.

Adenovirus Infections, Human↗
PubMed1982

[Barbital buffer in tablets as a solvent for complement fixation test (CFT)].

The purpose of this paper was to develop a tableting technology of barbital buffer as a standard diluent easy in use for complement fixation test (CFT). As starting point, barbital (veronal) buffer after Alton et al. [1] was assumed. Among 4 solubilizers polyvinyl pyrrolidone (PVP 10 000) was chosen, which provided a good solubility of the barbital in distilled water at 20 degrees C and it affected favourably the complement activity (C'). PVP 10 000 added to the components of barbital buffer at an amount of 0.275 per 10 tablets, in the form of solution for granulation, provided the required physical properties of the tablets. As compared with the barbital buffer after Alton et al. [1], the tablets produced affected favourably C' activity, decreased the range of spontaneous haemocyte lysis, and they did not effect CFT titers of two anti-Brucella abortus standard sera as well as 77 sera of cattle infected with brucellosis under natural conditions. The described physical and biological properties of the barbital buffer tablets with PVP addition indicate their usability as diluent for CFT. A standard diluent used in the form of tablets in all Poland's laboratories should provide a better reproducibility of CFT results in diagnostic examinations towards brucellosis as well as other infectious diseases in men and animals.

Animals↗
PubMed1996

Enzyme-linked immunosorbent assay, complement fixation test and immunoelectroprecipitation test in the diagnosis of Mycoplasma pneumoniae infections--comparative analysis.

Agreement of the results of determining antibodies against M. pneumoniae was evaluated by ELISA, complement fixation test (CFT) and immunoelectroprecipitation test (IEPT) in serum samples from 685 persons including 571 patients with respiratory tract infections and 114 clinically healthy subjects. Assuming the CF test to be the reference test, a very high correlation exceeding 0.95 was found, on the basis of the calculated correlation coefficient, between the results of the CF and IEP tests and the CFT and ELISA for all immunoglobulin classes. The highest sensitivity (92.3%) was displayed by the ELISA in relation to the CF test when determining mycoplasmal antibodies of Ig M and Ig A+G+M classes and a slightly lower sensitivity by the IEPT and ELISA when determining Ig G (83% and 82.1%, respectively). The lowest sensitivity was displayed by the ELISA when determining mycoplasmal antibodies of the Ig A class (53.4%). The specificity of both tests was high and exceeded 92%. The highest agreement of CFT and ELISA was obtained when detecting mycoplasmal antibodies in a diagnostically significant titre in the M and A+G+M immunoglobulin classes (> 92%) while the lowest agreement, although statistically significant, was obtained when detecting Ig A antibodies (74.7%).

Adolescent↗
PubMed1991

Evaluation of enzyme-linked immunosorbent assay in comparison with complement fixation test for the diagnosis of subclinical paratuberculosis in cattle.

An enzyme-linked immunosorbent assay (ELISA) was evaluated and compared in parallel with the standard complement fixation test (CFT) for the diagnosis of bovine subclinical paratuberculosis. Bovine sera preabsorbed with the mixture of Mycobacterium phlei and kaolin suspension were assayed for antibody activities to the crude protoplasmic antigen of Mycobacterium paratuberculosis in the ELISA. ELISA antibody titer was expressed as ELISA antibody index (EAI) value: EAI = (At-An)/(Ap-An), where At, Ap and An are the absorbance values of a 1:200 dilution of unknown test sera, a 1:400 dilution of positive control serum, and a 1:200 dilution of negative control serum. An EAI of 0.6 or greater was established as a reasonable cutoff point for a positive antibody titer by ELISA. Of the 156 sera from cattle with subclinical M. paratuberculosis-infection, 106 (67.9%) were positive by ELISA and 41 (26.3%) by CFT. Of the 3,880 sera from cattle in the herds which had no history or evidence of paratuberculosis, 3,875 (99.9%) were negative by ELISA, and 3,787 (97.6%) by CFT. Positive ELISA titers were detectable 1 to 5 months earlier than positive CFT titers in experimentally infected cattle, and 7 to 10 months earlier in naturally infected cattle. These results indicate that the ELISA should replace the CFT as the routine test of choice for the diagnosis of bovine paratuberculosis.

Animals↗
PubMedDate not supplied

Comparative evaluation of the Premier enzyme immunoassay, micro-immunodiffusion and complement fixation tests for the detection of Histoplasma capsulatum var. capsulatum antibodies.

A total of 178 sera, including 68 from proven cases of histoplasmosis (65 positive for the presence of Histoplasma capsulatum var. capsulatum antibodies and three positive for antigen), 93 from patients with suspected histoplasmosis but with no laboratory evidence of H. capsulatum var. capsulatum infection, 14 from humans with heterologous fungal and non-fungal infections and three from normal individuals, were tested for IgG H. capsulatum antibodies and M or M and H precipitins by enzyme immunoassay (EIA) (Meridian Diagnostics, Cincinnati, OH, USA) and microimmunodiffusion (MID) respectively. Sixty-three of the 68 histoplasmosis case sera demonstrated IgG antibody, and 65 of 68 demonstrated the presence of specific precipitins in the MID test. Nine positive case sera, when tested with the Laboratory Branch complement fixation (LBCF) test, reacted positively to whole yeast and histoplasmin antigens (titres 1:8 to 1:512). Three histoplasmosis case sera repeatedly tested negative for IgG, specific precipitins and complement-fixing antibodies, whereas they were positive for Histoplasma antigen. Eighteen of 95 sera from patients without evidence of histoplasmosis demonstrated IgG antibody in the EIA only. Among these positive sera, three out of three cases of aspergillosis and three out of five cases of blastomycosis were confirmed. Sera from HIV-infected and healthy individuals did not show IgG or M and/or H antibodies to H. capsulatum. Ninety-three sera were negative by both EIA and MID. The EIA for IgG was less sensitive (97%) than MID (100%). The specificity of EIA and MID was 84% and 100% respectively.

Antibodies, Fungal↗
PubMed1985

Comparison of enzyme-linked immunosorbent assay and complement fixation test for the detection of specific antibody in cattle vaccinated and challenged with Brucella abortus.

An enzyme-linked immunosorbent assay (ELISA) and a complement fixation test (CFT) were applied to sera collected regularly from 60 cattle challenged with Brucella abortus strain 544. Of the 60 cattle, 48 were vaccinated with either B. abortus strain 19 or B. abortus strain 45/20 as calves or adults. The remaining 12 cattle were not vaccinated. Of the 27 sera from cattle found to be infected at slaughter, 9 showed aberrant reactions to the CFT in that a positive titer after challenge was delayed or transient. The performance of the ELISA in these nine cattle with aberrant reactions and the other cattle in the trial was as follows. After vaccination with strain 19 or strain 45/20, the number of weeks at which the ELISA was positive was significantly greater (P less than 0.001) than that for the CFT. The strain 19 vaccine also induced positive responses to the CFT and the ELISA for a significantly longer period (P less than 0.001) than did the strain 45/20 vaccine. For cattle with aberrant reactions, the number of weeks after challenge when the ELISA was positive was significantly greater (P less than 0.001) than that for the CFT. For noninfected cattle, the average number of weeks after challenge when the CFT was negative (35 of 40) was higher than that for the ELISA (18 of 40).

Animals↗
PubMed1982

Alternatives to the standardized laboratory branch complement fixation test for detection of antibodies to Coccidioides immitis.

Antibody titers to Coccidioides immitis, using coccidioidin antigen, were determined by three methods: the standardized Laboratory Branch complement fixation method (LBCF), a modified version of the Viral and Rickettsial Disease Laboratory complement fixation test (VRDL-CF), and a quantitative immunodiffusion test (QID). Of the 133 samples evaluated, 72 were negative by each method and 57 (42 serum samples, 15 cerebrospinal fluid samples) were positive by all three methods. Four additional specimens (1 serum sample, 3 cerebrospinal fluid samples) were positive by QID alone. All positive patients were diagnosed clinically as having pulmonary or extrapulmonary coccidioidomycosis or both. When titers from two methods were compared, the agreement within +/- 1 dilution was VRDL-CF/QID, 88.5%; VRDL-CF/LBCF, 85.2%; and LBCF/QID, 82.0%. The agreement of these methods within +/- 2 dilutions was VRDL-CF/QID, 98.4%; VRDL-CF/LBCF, 96.7%; and LBCF/QID, 93.4%. The VRDL-CF and QID methods are simpler to perform; however, they are yet unrecognized as suitable alternatives to the more cumbersome LBCF. Our data show that they should be considered as options for C. immitis serology.

Antibodies, Fungal↗