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The indirect haemolysis test (IHLT) for bovine brucellosis - comparisons with the complement fixation test (CFT) in vaccinated and experimentally infected cattle.

Cattle were vaccinated with Brucella abortus strain 19 subcutaneously in doses ranging from the normal (2.0 ml) dose of standard vaccine down to 1/400 of the normal dose, and via the conjunctival sac with 1/2 of 1/20 of the normal dose. Under all vaccination regimes serum antibody titres in the complement fixation test (CFT) rose more rapidly, reached higher levels, declined more slowly and involved a greater proportion of animals, than titres in the indirect haemolysis test (IHLT). The interval between the first positive serological test and parturition was determined for 54 pregnant cows infected with a virulent field strain (VRI 3) of B. abortus. On average the CFT titre rose to 1/4 43 days, and 1/8 33 days, before parturition, while the IHLT reached a 2/8 reaction 31 days before parturition.

Animals↗

An evaluation of the Technicon Autoanalyzer for automating complement-fixation tests.

Obviously there is need for a reliable means of automating complement-fixation tests. This paper offers an account of experience with an AutoAnalyzer adapted for this purpose. Results of syphilis screening tests done by the AutoAnalyzer compared with those of tests performed manually showed satisfactory agreement, the automated method being slightly less specific in our hands. There were no false negative results with the AutoAnalyzer if both Maltaner and Reiter protein antigens were used. The current design of the AutoAnalyzer contains three major shortcomings if it is to be used for large numbers of complement-fixation tests. First and foremost is the relatively slow sampling rate compatible with adequate sample discrimination. Second is the necessity for frequently replenishing the machine with samples. Third is the need for adjusting or cleaning the flow-cell during use.

Autoanalysis↗

Problems in the diagnosis of Q fever by complement-fixation tests.

For the selection of a suitable antigen concentration for use in routine complement-fixation tests with Q-fever antisera, a rigid system of antigen units is unsatisfactory. The optimum antigen dilution should be judged after inspection of the results of full "chess-board" titrations with a variety of antisera. Non-specific reactions may occur with sera from patients with primary atypical pneumonia or sera which have deteriorated during storage. These may be detected with a typhus antigen or some similar control antigen.Nine Mile and Henzerling strain antigens, which are widely used for routine diagnosis, were compared in tests with 868 sheep sera, 1055 human blood-donor sera, 66 human convalescent sera, and 20 guinea-pig sera. Considerable discrepancies were found in the results obtained with the two antigens.Irrespective of antigen concentration, the Nine Mile strain was more sensitive than the Henzerling strain for the detection of Q-fever antibody in human and guinea-pig sera and in some sera from Welsh sheep. With antibody in Kentish sheep sera, on the other hand, the Henzerling antigen was markedly more sensitive than the Nine Mile strain antigen. It is concluded that these two strains cannot be regarded as interchangeable, and the choice of antigen must depend on the geographical area and the species to be tested.

Animals↗

Verification of tween-ether antigen for complement fixation test in the diagnostics of toxoplasmosis.

Tween-ether toxoplasma antigen for the complement fixation test was verified on a more extensive clinical material. From a series of 949 patient's sera, positive reaction was obtained in 44% of samples with the tween-ether antigen and in only 33.5% of samples with the FT antigen. All sera, giving positive results only with the tween-ether antigen, were also positive in the Sabin-Feldman test. The authors believe that by using this type of more sensitive antigen, containing also the cell-wall components of Toxoplasma gondii, it would be possible to standardize serological examination by the complement fixation test on the basis of an international standard serum.

Animals↗

Comparative study between microscopic agglutination and complement fixation tests in experimental canine leptospirosis.

In order to evaluate the antibody response to pathologic leptospira from both serovars icterohaemorrhagiae and canicola, dogs were experimentally inoculated with these leptospiras. Each of the serovar were inoculated in 15 dogs and the antibody response in the acute phase of infected was followed by microscopic agglutination and complement fixation tests. Complement fixing antibodies were detected in both groups at the 4th day post infection and agglutinins appeared in circulation at the 7th day post infection when homologous antigens were used. On the 63rd day post infection with serovar canicola and on 56th day post infection with serovar icterohaemorrhagiae, complement fixing antibodies could no longer be detected but, in both experimental groups, specific agglutinins were presented in significant titers.

Agglutination Tests↗

Isolation of mycobacteria inducing cross-reactions in the complement fixation test for Johne's disease.

Eight bulls which gave positive reactions in the complement fixation test for Johne's disease were identified in a group of 29 bulls which had previously given only negative reactions at repeated annual tests. One reacting bull was confirmed to be infected with Mycobacterium paratuberculosis at autopsy, but another reactor which was slaughtered had no visible lesions and mycobacteria were not recovered in culture. Faecal samples from seven further bulls (six reactors and one non-reactor) yielded mycobacteria which were not dependent on mycobactin for growth. When one of these strains was injected into two calves they developed positive reactions in the complement fixation test for Johne's disease and to intradermal skin testing with purified protein derivatives of M avium, M paratuberculosis and M bovis. The strains did not satisfy the exact requirements for classification into any recognised mycobacterial species.

Animals↗

Evaluation of a modified complement fixation test and an indirect hemagglutination test for the serodiagnosis of melioidosis in pigs.

A complement fixation test modified by the addition of porcine serum and an indirect hemagglutination test were used to detect antibodies to Pseudomonas pseudomallei in pigs. These tests together with cultural examinations were carried out with 250 pigs. The sensitivity and specificity values were 79.3 and 99.5% and 82.8 and 93.2% for the modified complement fixation and hemagglutination tests, respectively. When results from the combination of both tests were considered, the values were 86.2 and 92.8%, respectively.

Animals↗

Diagnosis of human rotavirus infections: comparison of an electrophoretic method, a modified complement fixation test and electron microscopy for rotavirus detection.

A modified complement fixation test and a counter-immuno-electrophoresis on cellulose acetate were compared to electron microscopy, in detecting Rotavirus from stool specimens. Out of 75 samples from patients with acute gastroenteritis, 40 per cent yielded positive results. The main advantages of the above two methods in routine diagnosis are discussed.

Complement Fixation Tests↗

Effect of Eperythrozoon ovis on the lysis of sheep erythrocytes in the complement fixation test.

When erythrocytes from sheep experimentally infected with Eperythrozoon ovis were used in the titration of reagents for a standardised complement fixation test, increased amounts of both haemolysin and complement were required for erythrocyte lysis compared with preinfection titrations. The haemolysin requirement increased by up to 125% at 55 days post-infection and complement requirement increased by up to 40% at 40 days post-infection. These changes appeared to correlate with the development of a macrocytic anaemia in affected sheep rather than E. ovis parasitaemia. The results emphasise the need to carefully monitor the haematological parameters of sheep used as sources of erythrocytes for the complement fixation test.

Anaplasmataceae Infections↗

A complement fixation test for visceral leishmaniasis using homologous parasite antigen I.

The complement fixation test using homologous parasite antigen was evaluated in 60 individuals with confirmed visceral leishmaniasis and compared with the results obtained in individuals with other parasitic and infectious diseases; 88% of the confirmed cases of visceral leishmaniasis were positive whilst no positive reactions were observed in individuals with other infectious and parasitic diseases. The specificity was partially compromised by anticomplementary activity in 5%, limited to individuals with visceral leishmaniasis, and doubtful (2%) or sero-negative (7%) results.

Antigens, Protozoan↗

A complement fixation test for antibody to the contagious equine metritis organism.

A complement fixation test (CFT) based on that used for brucellosis (Brinley Morgan and others 1971) has been developed for use on the sera of horses exposed to the contagious equine metritis (CEM) organism. None of 50 single samples from horses thought to be unexposed to the CEM organism was positive to the test, although five showed inconclusive reactions. Samples were examined from 41 mares either proved to be infected or from an infected stud. Of these 21 were positive, 11 were inconclusive and nine were negative. The relationship of the CFT to reactions in the other tests used in this condition is discussed--the serum agglutination test (SAT) and antiglobulin test (AGT) (Benson and others 1978). Complement fixing antibodies appear to remain for a longer period in the infected animal, and are therefore more likely to be of use in the diagnosis of the chronic carrier state.

Agglutination Tests↗

A short, reliable, highly reproducible complement fixation test for the serological diagnosis of contagious equine metritis.

A complement fixation test, using round-bottomed microtitration plates and an 8 channel microdiluter, based on that used for brucellosis by Herr, Huchzermeyer, Te Brugge, Williamson, Roos & Schiele, 1985, has been developed for use on the sera of horses to detect antibodies to the contagious equine metritis organism. The results with 2 known positive sera tested 116 times in 27 separate tests were reproducible for the most part within a twofold range. They seldom exceeded these limits and never exceeded a fourfold range. The test itself is capable of being carried out within 90 min. The test was slightly more sensitive when sera were inactivated in a hot air oven for 50 min at 58 degrees C, as compared to inactivation at 62 degrees C in a water-bath for 50 min. There were no false negative or false positive reactions and no anticomplementary activity in the sera tested.

Animals↗

A new complement fixation test for toxoplasmosis. Comparison with other serological methods.

A new complement fixation test for toxoplasmosis has been compared with the classical test indirect immunofluorescence test (IFAT) and indirect haemoagglutination test (IHAT). Neither false positive or negative results were obtained with LBCF-H100-TTE. Notably these values correlate well with IFA titers. Furthermore LBCF-H100-TTE shows the highest titers in acute cases and its time course is practically superimposable to IFAT. The differences obtained performing these different tests on the preferential detection of different antigen antibodies systems by these 3 tests are discussed.

Complement Fixation Tests↗

Improvement of complement fixation test antigen for the diagnosis of Mycoplasma hyopneumoniae infection.

Several attempts were made to develop a complement fixation test antigen which is useful and practicable for the diagnosis of mycoplasmal pneumonia of swine. For the preparation of antigen, Mycoplasma hyopneumoniae was grown in broth medium containing horse serum for 14 days by shaking culture. Anticomplementary activity of antigen was eliminated by addition of complement and heating at 56 degrees C for 30 minutes. Storage of this antigen at 4 degrees C or at room temperature for 12 months had no significant effect on antigen titer. In the complement fixation test with this antigen, complement-fixing antibodies could be detected up to 41 weeks after experimental inoculation by KIO4 treatment of serum. They were demonstrated in 81.4% of 296 sera collected at slaughterhouses in five prefectures.

Animals↗