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Species-specific serodiagnosis of equine piroplasma infections by means of complement fixation test (CFT), immunofluorescence (IIF), and enzyme-linked immunosorbent assay (ELISA).

The increasing horse trade requires a reliable immunodiagnosis of equine piroplasma infections due to import restrictions imposed by various countries, including the United States of America. It was the aim of our investigations to establish the suitability of serological tests for the detection of parasite carriers and, eventually, to differentiate between Babesia caballi and B. equi infections. The investigations were carried out on 11 ponies with experimentally-induced B. caballi and/or B. equi infection. The infections were confirmed by the demonstration of parasites in blood smears 2-13 days post infection (PI). The complement fixation test (CFT), the indirect immunofluorescence (IIF) and the enzyme-linked immunosorbent assay (ELISA) were employed for the demonstration of antibodies, and different antigen preparations were tested for their suitability. Antibodies could be demonstrated by all three tests. Complement-fixing antibodies disappear after 2-3 months PI in B. caballi-infected horses, while the IIF and ELISA gave positive results during latent infection. A reliable serodiagnosis thus requires the use of the CFT and IIF, since parasite carriers may appear seronegative by the CFT. Serological differentiation between B. caballi and B. equi was possible by CFT and, to a certain extent, by IIF during early infection, but not by ELISA. The successful treatment of B. caballi infections with Berenil could only be confirmed serologically by IIF.

Animals↗

[The value of the Coxsackie B virus complement fixation test (author's transl)].

Enteroviruses were isolated from 27 patients during 1973 and 1974, 21 of these were Coxsackie B, 4 were ECHO and 2 were polio viruses, 5 further viruses could not be identified. Sera from 14 of the Coxsackie patients were investigated twice by means of the Complement Fixation Test (CFT). 11 of them showed a significant rise in antibody titre against one of the 6 different Coxsackie B viruses. No strong correlation was established between the result of the CFT and the isolated type of virus. Nevertheless, the CFT can be helpful in the diagnosis of a Coxsackie B infection. About 200 such cases with varied clinical features were diagnosed in the Department of Virology, Vienna University over the past 3 years by means of the CFT.

Adult↗

Evaluation of the ELISA and comparison to the complement fixation test and radial immunodiffusion enzyme assay for detection of antibodies against Mycoplasma hyopneumoniae in swine serum.

An enzyme-linked immunosorbent assay (ELISA) was evaluated for detection of antibodies (Ab) against Mycoplasma hyopneumoniae and M. flocculare in sera from swine experimentally infected with these agents. In addition, the ELISA was compared with the complement fixation test (CFT), and radial immunodiffusion enzyme assay (RIDEA) for the demonstration of Ab against M. hyopneumoniae. Twenty two 6-week-old swine from a respiratory disease-free herd were divided into five groups. Two or three pigs from each of the four groups were inoculated, respectively, with M. hyopneumoniae or with M. flocculare while two pigs in each group were contact exposed to the inoculated penmates. A fifth group, consisting of three pigs, served as inoculated controls. Pigs inoculated with M. hyopneumoniae began coughing 13 days post inoculation (PI). Antibodies were first detected 2 weeks PI with the CFT, 3 weeks PI with the ELISA, and 5 weeks PI with the RIDEA. With the ELISA and RIDEA, Ab were still detectable one year PI at a very low level. With the CFT, Ab were not detectable in sera from any swine beyond 5 months PI. At necropsy 1 year PI, no lesions were detected in lungs of any of the animals nor were mycoplasmas detected. M. flocculare inoculated or contact-exposed pigs never evidenced clinical signs. Antibodies against M. flocculare were first detected 5 to 12 weeks PI with CFT, and 6 to 12 weeks PI with the ELISA. Peak optical density (OD) values obtained in the ELISA with M. flocculare Ab were as high as the values obtained with peak M. hyopneumoniae Ab titers. Levels of Ab against M. flocculare were at relatively higher OD at 1 year PI than Ab against M. hyopneumoniae. Sera with high levels of Ab against M. flocculare cross-reacted slightly with M. hyopneumoniae antigen in immunoblotting and ELISA.

Animals↗

Preliminary investigations on the diagnostic value of passive hemagglutination and complement fixation tests in infections with Mycoplasma pneumoniae.

In order to evaluate the efficiency of passive hemagglutination (PHA) and complement fixation (CF) tests for the diagnosis of M. pneumoniae infections, 144 serum samples--out of which 81 from patients with respiratory and cutaneous infections and 63 from subjects with other diseases (controls)--were comparatively investigated by the two methods. The PHA test made evident a positivity index of 65% in the case of mixed pneumonias, as against 17% in controls, while the results obtained by CF were almost identical in the two groups investigated. The high specificity and sensitivity of the PHA reaction recommend this method for the diagnosis of acute M. pneumoniae infections.

Antibodies, Bacterial↗