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Improving the specificity and yield of the contagious bovine pleuropneumonia complement fixation test antigen.

Several methods for increasing yield and specificity of the contagious bovine pleuropneumonia complement fixation test antigen which is derived from Mycoplasma mycoides subsp mycoides, strain V5, were examined. Changes in culture conditions that increased the cell mass per unit volume of culture did not result in comparable increase in antigen yield. Sixteen to 60-day-old cultures yielded more boiled cell antigen than younger cultures. Some antigen in young cultures appeared to be masked, probably by galactan. The yield of antigen extracted from boiled cells with ethonol was as much for two to eight-day-old cultures as for older cultures. The ethanol extract antigen was less reactive with false positive bovine sera than standard boiled antigen while reactivity with anti Mycoplasma mycoides sera was similar to that of standard antigen. Adsorbed gamma globulin was not detected in either boiled or ethanol extract antigen. The data suggest that several complement fixing antigens were present in antigens derived from older cultures.

Animals↗

Rotavirus antibody assays on monkey sera: a comparison of enzyme immunoassay with neutralization and complement-fixation tests.

An enzyme immunoassay (EIA) for the detection of rotaviral antibodies was developed, using a purified, cell culture-grown SA 11 viral antigen and alkaline phosphatase as an enzyme label. This technique was evaluated by comparative testing with tube neutralization and complement-fixation assays on a collection of simian sera. There was close correlation between positive and negative results obtained by EIA and by neutralization. The EIA was as easy to perform as complement fixation testing, but showed greater sensitivity and fewer nonspecific reactions. Thus, EIA was shown to be a very suitable test for routine detection of rotaviral antibodies in serum. Results of neutralization tests suggested that the monkeys (mostly rhesus macaques) in the present study were infected with viruses varying in their antigenic relatedness to SA 11 virus and to a British isolate of calf rotavirus.

Animals↗

Cross-reactivity of Haemophilus somnus antibody in agglutination and complement fixation tests and in the enzyme-linked immunosorbent assay.

The specificity and sensitivity of agglutination, complement fixation, and enzyme-linked immunosorbent assay (ELISA) procedures in the detection of antibodies to Haemophilus somnus was investigated. H. somnus rabbit immune sera were found to agglutinate Pasteurella multocida, Staphylococcus aureus, and Haemophilus agni and, in some instances, also Pasteurella haemolytica, Salmonella dublin, Streptococcus agalactiae, and Corynebacterium pyogenes. In complement fixation tests with saline extracts as antigens, only H. agni reacted with H. somnus antisera to any significant degree. In ELISA tests with sonicated or heat-extracted antigens, cross-reactions were seen with the two Pasteurella spp. and with H. agni. When whole cells and saline extracts were used as antigens in ELISAs, only H. agni showed any cross-reactivity. The greatest specificity in distinguishing homologous from heterologous reactions was achieved by ELISA with saline extracts as antigens. Escherichia coli and Brucella abortus antigens failed to react with H. somnus antibody in any of the tests. A rabbit serum containing antibody to bovine type isolates of P. multocida, P. haemolytica, S. aureus, S. agalactiae, S. dublin, C. pyogenes, and E. coli gave no positive reaction in ELISA tests with saline extract of H. somnus as antigen. It is concluded that such saline extract, which appears to consist largely of H. somnus common antigen, has the potential of being a useful diagnostic reagent in the study by ELISA of antibody response to H. somnus.

Agglutination Tests↗

Detection of type-specific antibody to herpes simplex virus type 1 and 2 in human sera by complement-fixation tests.

Type-specific antigens for herpes simplex virus type 1 and 2 were prepared by rigorous absorption of cell extracts with heterotypic immune sera. Type-specificity was demonstrated by immunodiffusion and complement-fixation tests against immune sera prepared in rabbits. Specific type 1 complement-fixing reactivity was detected in eleven of fifteen sera from Roman Catholic nuns and in two convalescent sera from patients with recurrent herpes labialis; these sera had been previously shown to contain neutralising and complement-fixing antibody to herpes simplex virus. Three of the non-reacting sera contained low or absent levels of type-common complement-fixing reactivity and other contained no type-specific neutralising antibody. With the exception of three "acute" sera, specific type 2 complement-fixing reactivity was detected in every convalescent or interim serum obtained from patients with a virologically-proven history of type 2 herpes virus infection. It is suggested that complement-fixation testing using these absorbed type-specific antigens preparations may provide a convenient and rapid method for the identification of type-specific antibody in human sera.

Antibodies, Viral↗

Mechanization of a micro complement fixation test for the serodiagnosis of human toxoplasmosis.

A description is given of a mechanized micro complement-fixation test for the serodiagnosis of human toxoplasmosis. Besides a reduction in the quantity of reagents by using a microplate a considerable advantage of the test is the mechanization of actually all steps. Examination of large numbers of sera can be realized in a relatively short period of time. In order to test the sensitivity of the micro CF test comparative studies were carried out with the macro CF test and the immunofluorescence (IF) test on 549 human sera. The micro CF test proved to be more sensitive than the macro CF test. The results obtained with the micro CF test were in better agreement with the IF test than those obtained with the macro CF test.

Autoanalysis↗

[An ELISA test for detection of maedi-visna antibodies. Comparative study with gel immunodiffusion and complement-fixation test].

An indirect microELISA test was performed for detection of maedi-visna antibodies in ovine and caprine species. The antigen consisted in viral particles, highly purified by successive ultracentrifugations. By comparative testing of 934 sera in ELISA and gel immunodiffusion, we found a good correlation between these two tests, and moreover, ELISA revealed another 11.3% of positive samples. The precocity of this ELISA was shown by experimental infection of sheep with different strains of maedi-visna: positive sera were detected 7 weeks post-infection, instead 4-5 months with gel immunodiffusion. The complement fixation test was compared with gel immunodiffusion and was found the less sensitive. This ELISA test appeared to be satisfactory, and may be used for early diagnosis of maedi-visna infection.

Animals↗

Serological studies on leprosy. A comparison of complement-fixation tests using antigens prepared from tubercle bacilli and beef-heart lipids with other serological reactions.

Sera from lepromatous leprosy patients were subjected to a battery of serological tests, including flocculation, agglutination and complement fixation. A correlation was found between the antileprous antibody content and the reactivity with "cardchol" antigen, but not with Trypanosoma cruzi antigen, cardiolipin or Rubino antigen. The reactivity of leprous sera with tubercle bacilli antigen in the quantitative complement-fixation test decreased in three patients with lepromatous leprosy during sulfone treatment. When syphilis was present in a lepromatous leprosy case, it was possible to follow the effect of specific treatment of the two infections, with sulfone and with penicillin, by the drawing of two serological curves-one for leprosy and one for syphilis.

Animals↗

Comparison of a complement fixation test, a gel diffusion test and two absorbed and unabsorbed ELISAs for the diagnosis of paratuberculosis in sheep.

A complement fixation test for paratuberculosis, a gel diffusion test and two enzyme-linked immunosorbent assays (ELISA) were evaluated using sera from Mycobacterium paratuberculosis infected and non-infected sheep. Gross pathology and histopathology were used as parameters of infection. The two ELISAs, one of which is commercially available for testing cattle, were used before and after sera had been absorbed with a soluble sonicate of Mycobacterium phlei. Differences between the various tests and between ELISAs before and after absorption were non-significant (P > 0.05) in non-infected sheep or in animals with gross or histopathological lesions. The specificity of all the tests was at least 97%. Sensitivity in histopathologically positive sheep was at least 98%. Sheep from infected flocks but without histopathological lesions showed serological results which were poorly correlated between the various tests.

Animals↗

Serological and necropsy findings for rams infected with Brucella ovis which were not identified by the complement fixation test.

The eradication of Brucella ovis from a commercial flock of 36 Romney rams was complicated by four infected rams remaining undetected despite four successive flock examinations using the complement fixation test. These four rams were subsequently tested using an enzyme-linked immunosorbent assay and a gel diffusion test and shown to be infected by semen culture. All four rams could have been identified as infected at the initial test if the enzyme-linked immunosorbent assay had been used in addition to the complement fixation test. Although gross evidence of epididymitis was found in only one ram at necropsy, three had histological lesions of epididymitis and all four had a seminal vesiculitis.

Journal Article↗