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PubMed1975

A specific complement-fixation test for human hepatitis a employing CR326 virus antigen. Diagnosis and epidemiology.

A specific diagnostic complement-fixation test for hepatitis A antibody in human serum was described employing livers of marmosets infected with CR326 strain human hepatitis A virus. Persons with hepatitis A, but not hepatitis B, developed hepatitis A CF antibody shortly after the onset of illness and this persisted thereafter. Good agreement was noted in the development of CF and neutralizing antibodies in hepatitis A cases. Hepatitis A was shown to occur in a person with hepatitis B antigenemia and hepatitis B occurred in persons with hepatitis A antibody. Most persons with hepatitis A who were tested, but none of those with hepatitis B, developed increased anticomplementary activity in their sera at the time of onset of illness. At least one patient with hepatitis A developed antibody against normal liver that persisted. The possible inplications of this in relation to pathogenesis and to non-specific diagnostic tests in hepatitis were discussed. A limited epidemiologic study of a family outbreak of hepatitis in Costa Rica and of a group of young adults in our epidemic country acquire their infections at an early age and are immune thereafter; persons in areas of relatively low incidence may proceed into adulthood without experience with hepatitis A. The CF test should provide an excellent tool for diagnosis and for epidemiologic investigation of hepatitis A and should be of considerable value to detect hepatitis A virus in attempts to propagate the virus in cell culture.

Adolescent↗
PubMed1976

A comparison between the haemagglutination inhibition and complement fixation tests for Newcastle disease.

The value of the complement fixation (CF) test as a means of assessing the immune response of fowls to Newcastle disease virus was examined using several strains of virus. A close degree of correlation was found between the CF test and the simpler haemagglutination-inhibition (HI) test. Like the HI test, the CF test only gave an indication of the immune status and was not a direct measurement of immunity.

Animals↗
PubMed1977

Complement fixation test of Nebraska calf diarrhea virus with calf serum.

A complement fixation (CF) test for neonatal calf diarrhea has been developed with Nebraska calf diarrhea virus (NCDV) as antigen. The CF antigenicity of NCDV appeared in BK cell cultures for the first time 3 days after inoculation. Usually, the unconcentrated BK cell culture fluid infected with NCDV possessed poor CF antigenicity. The fluid concentrated by ultracentrifugation and ultrafiltration and with polyethylene glycol 6000 revealed a high-titered CF antigenicity to antiserum against NCDV. The antigen was not sensitive to lipid solvents, but was relatively resistant to heating. It was recognized that the concentrated fluid of cell culture infected with NCDV was available as antigen in the CF test for the serological demonstration of infection with a calf reovirus-like agent. The wide prevalence of diarrhea among Japanese calves with the calf reovirus-like agent was revealed from the results of CF and neutralization tests of NCDV.

Animals↗
PubMed1980

A complement-fixation test for enzootic pneumonia of pigs using a complement dilution method.

Complement-fixing antibody to Mycoplasma hyopneumoniae in the serums of pigs experimentally infected with enzootic pneumonia was demonstrated by comparing the haemolytic titre of guinea-pig complement titrated in the presence of heated test serum, M. hyopneumoniae antigen and unheated normal pig serum with the titre obtained when the antigen was omitted. The haemolytic titres against sensitised sheep erythrocytes were determined after a fixation period of 16 to 18 hours at 5 degrees C. When serums, collected at intervals of 3 to 7 days, from 43 pigs exposed to pigs experimentally infected with enzootic pneumonia were tested, 4.6 or more complement units were first fixed 14 to 44 (mean 23.4) days after contact began. Serums collected subsequently fixed from 4.6 to more than 31 complement units. This positive reaction usually persisted until the pigs were killed 4 to 35 weeks after contact began. Thirty-three had gross enzootic pneumonia lesions and 9 had lung lesions detected microscopically. Serum antibody was not detected in 73 weaned pigs aged 7 weeks in a pneumonia-free herd but serums from 9 of 15 unweaned piglets aged 9 to 14 days in the same herd, fixed between 3 and 7 complement units.

Animals↗
PubMed1975

A rapid slide flocculation test for the diagnosis of American trypanosomiasis using Trypanosoma cruzi fragments preserved by lyophilization. Comparison with hemagglutination, immunofluorescence, and complement fixation tests.

A slide flocculation test for Chagas' disease is described, which uses a lyophilized, stable antigen obtained by formalin and ultrasonic treatment of culture forms of Trypanosoma cruzi. The test was compared with other tests for the serodiagnosis of American trypanosomiasis and showed a high sensitivity, positive results being obtained in every case of acute or chronic Chagas' disease. In sera from blood donors and from normal individuals with negative T. cruzi antigen complement fixation tests a specificity of 96% was found. False positive flocculation tests were seen, especially in cases of South American blastomycosis and in a few cases of acute toxoplasmosis. Since it is easy and quick to perform, the slide flocculation test can be recommended as a screening procedure, especially for blood banks.

Bacterial Infections↗
PubMed1983

Comparison of the enzyme-linked immunosorbent assay and the indirect hemagglutination and complement fixation tests for detecting antibodies to Mycoplasma hyopneumoniae.

Caesarean-derived, colostrum-deprived swine were exposed to a broth culture of a low passage field isolate of Mycoplasma hyopneumoniae by intranasal inoculation. The intranasal-inoculated swine subsequently were commingled with their litter-mates to effect transmission via contact-exposure. Sera were collected from the swine at two to four week intervals for approximately one year postexposure and evaluated by the enzyme-linked immunosorbent assay (ELISA), indirect hemagglutination and complement fixation tests. The intranasal-exposed swine seroconverted earlier, developed higher titers and remained indirect hemagglutination and complement fixation positive longer than the contact-exposed swine. It was concluded that the antibody response of intranasal-exposed swine was artificially high and that sera from such swine were not suitable for evaluating the sensitivity of mycoplasmal pneumonia of swine serodiagnostic tests. The indirect hemagglutination test was relatively insensitive and technically cumbersome and the least promising as a practical field test. The complement fixation test appeared to be slightly more sensitive in detecting early antibody production (especially in contact-exposed swine) but it was the least sensitive in detecting late antibodies. The ELISA was generally the most sensitive procedure. Individual high ELISA titers were from ten to 32 times greater than maximum complement fixation and indirect hemagglutination titers. The most striking difference among the three tests was the persistence of high ELISA titers late in the study. All swine were ELISA positive at necropsy approximately one year postexposure despite the fact that lungs were devoid of lesions and culturally and immunofluorescent negative for M. hyopneumoniae.

Animals↗
PubMed1986

A reappraisal of the complement fixation test using soluble Mycobacterium avium antigen for the detection of M. paratuberculosis infection in cattle.

Serums from 263 cattle suspected of having paratuberculosis on the basis of clinical signs, were tested for antibodies to Mycobacterium paratuberculosis with a complement fixation test (CFT) employing a heat extracted, soluble M. avium antigen. Microscopic examination confirmed that 172 (65.4%) clinically affected animals had paratuberculosis, the remainder being disease-free. The specificity and sensitivity of the CFT was 92.3% and 74.4% respectively. Phenol treatment of serums before testing was compared with no treatment and was found to have no significant effect on the CFT titres. Results obtained are discussed in relation to the cause of false negative and false positive reactions.

Animals↗
PubMed1975

An improved quantitative micro-complement fixation test.

The technical procedures for a simple quantitative micro-complement (C) fixation test are described. Major advantages of the present technique compared with the previously described method are: a) a simple measurement of the residual hemolytic activity of C by counting the radioactivity released from 51Cr-labeled sensitized sheep erythrocytes (51Cr-EA); b) an increased sensitivity of the test, brought about by the use of a relatively small number of 51CR-EA per reaction volume; and c) an increased specificity of the test, achieved by maintaining a constant amount of C available for the specific antigen--antibody reaction.

Adenoviridae↗
PubMed1979

The complement fixation test and African trypanosomiasis: I. Experimental infection and re-infection in cattle before and after treatment.

The complement fixation test was applied to assess antibody responses in cattle infected with T. brucei, T. congolense, and T. vivax which had been treated and re-infected. After the first infection, the specificity of the results was low in T. congolense, fair in T. brucei, and high in T. vivax infected animals. After re-infection with the same trypanosoma species as used for previous infections, the specificity of CF results was high in all cases. After a foregoing T. vivax infection, specific titres of T. congolense and to a lesser degree of T. brucei infections were frequently masked by residual T. vivax titres. After treatment of trypanosoma-infected cattle the fasted drop of CF antibody titres occurred in T. congolense cases, followed by T. brucei infections. T. vivax titres persisted over prolonged periods.

Animals↗
PubMed1983

Comparison of radioimmunoassay with the complement fixation test and the indirect haemolysis test in the field diagnosis of bovine brucellosis.

Sera were collected from female cattle in 118 commercial herds being subjected to a programme to eradicate brucellosis by test and slaughter, in an area in which vaccination of heifer calves with Brucella abortus strain 19 was compulsory. Of 4583 sera positive by the Rose Bengal plate test, the brucellosis radioimmunoassay was positive for 1524, the complement fixation test for 1363 and the indirect haemolysis test for 1141. These figures, and supporting evidence from the eradication programme, suggest that the radioimmunoassay may be a useful supplementary test in problem herds.

Animals↗
PubMed1975

[Study of the outcome of pregnancy in sheep with positive serologic reactions to toxoplasmosis according to the complement fixation test].

Studied were five flocks of 240 sheep each. It was found that prior to impregnation the positive complement-fixation test (c. f. test) reagents varied from 16 to 61 per cent with titers ranging from 1:50 to 1:10. Abortions, however, were established only in two of the flocks consisting of young sheep, aged 3 and 4 years, at the first or second lambing. The abortions took place in the fourth month of pregnancy. In one of these flocks having 43 per cent positive reagents there were 40 per cent returns, and 28 of the ewes miscarried, 12 of them being positive for toxoplasmosis. In the second flock there were 61 per cent positive reagents, and 9 of the ewes miscarried, 5 of them being positive for toxoplasmosis. In the remaining three flocks consisting of 5-year-old sheep there were no abortions. The ewes that miscarried and were positive for toxoplasmosis showed a rise in their serum titers: from 1:40 on the 15th day after the abortion to 1:80 on the 30th day. It is believed that in these sheep the abortions are not due to toxoplasmosis, and in sheep flocks with a high percent of positive toxoplasmosis reagnets there may not be abortions.

Abortion, Veterinary↗