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Comparison of serological tests for the diagnosis of Chlamydia psittaci infection of sheep.

An enzyme-linked immunosorbent assay (ELISA) was developed and compared with the complement fixation test (CFT) and the indirect immunofluorescence antibody test (IIFAT) for the detection of antibodies to C. psittaci in sheep. Field sera and experimental sera from aborting ewes, subclinically infected sheep and vaccinated sheep were used. The ELISA and IIFAT were much more sensitive than the CFT. Agreement between the CFT and ELISA varied between 50% and 98%, while agreement between the IIFAT and ELISA varied between 70.5% and 94.3%. The specificity of IIFAT and ELISA with regard to the identification of animals which may be a source of ovine abortion strains of C. psittaci was critically assessed, using antigen preparations derived from an abortion isolate and from a non-abortion isolate of C. psittaci. Indirect immunofluorescence was shown to be the more discerning test.

Abortion, Veterinary↗

Serosurvey for antibodies against Brucella abortus and Leptospira interrogans in pampas deer from Brazil.

A survey for antibodies against Brucella abortus, and Leptospira interrogans was conducted on 17 pampas deer (Ozotocerus bezoarticus) from Pantanal Matogrossense (State of Mato Grosso do Sul, Brazil) and on 24 pampas deer from Parque Nacional de Emas (State of Goiás, Brazil). Antibodies against B. abortus were detected by plate agglutination, rose Bengal, and complement fixation tests; antibodies against Leptospira interrogans were detected by the microscopic agglutination test. All sera were negative for B. abortus antibodies and all deer sera from Parque Nacional de Emas were negative for L. interrogans antibodies. Four (24%) of 17 sera from Pantanal Matogrossense were positive for L. interrogans serovar (n = 2) hardjo, wolffi (n = 1) and mini (n = 1). While these diseases do not appear to be of major importance to the health status of Pampas deer, it appears that deer are reservoir for leptospirosis in one of the study areas.

Agglutination Tests↗

[Serologic demonstration of antibodies against Campylobacter jejuni/coli in man].

Antibody response to Campylobacter jejuni/coli infections in man was studied by microagglutination assay against homologues organisms isolated from patients and by complement fixation test against a commercially available group-specific antigen of C. jejuni/coli. Titers of agglutinating antibodies raise within 1-2 weeks post infectionem (p.i.) to an extent of about 320 (reciprocal titer) and persist about 3-4 months. CF-antibody titers raise only to about 40 but they persist for a long time. Because of the low titers in the CF-test and because of a missing seroconversion the CF-test is not suitable for the diagnosis of an acute infection. On the other hand the persisting CF-antibodies allow the diagnosis of reactive arthritis caused by C. jejuni/coli, particularly if the causative bacteria could not be cultivated.

Agglutination Tests↗

Application of agar-gel precipitin test for the detection of Sendai virus antibody in rat sera.

A simplified agar-gel precipitin test was performed for the detection of Sendai virus antibody in rat sera. A close correlation was observed between detection of antibodies by complement-fixation test and agar-gel precipitin test. No correlation was found between results obtained by hemagglutination-inhibition test and agar-gel precipitin test in sera with HI titer of less than 1:8.

Animals↗

[Differentiation of non-specific positive brucellosis reactions using an antigen stained with rose bengal].

A Brucella buffered antigen, stained with Bengal rose by a method of the authors, was obtained. It showed a high distinguishing capacity with regard to the nonspecific agglutinations after Huddleson and Wright at a negative complement-fixation test for brucellosis with sera from cattle, pigs, sheep, and horses. Such differentiation, however, proved to be incomplete and for sera of different animals varied within the range of 34 to 0.0 per cent.

Agglutination Tests↗

The serological diagnosis of whooping cough.

Indirect haemagglutination (IHA), agglutination and complement fixation tests (CFT) for Bordetella pertussis antibodies were compared on paired sera from 52 suspected cases of whooping cough and single sera from 83 children with no recent history of whooping cough. All three tests detected serotype antibodies 1, 2 and 3, but the IHA test was the most sensitive; in seven cases it was the only test to show a rise in titre. It is recommended, particularly with vaccinated children, that the serological diagnosis of whooping cough should be based upon a rise in titre. There should be a gap of at least 2-4 weeks between serum samples, depending on the age and vaccination state of the child. The CFT appears to detect a different antibody from that detected by the other two tests, and in three cases it was the only test to show a rise in titre.

Adolescent↗

Hepatitis-associated antigen in sporadic cases of acute viral hepatitis.

Serum specimens collected during the period from September 1970 to April 1971 from hospitalized patients and apparently healthy staff members at risk were tested for the presence of hepatitis-associated antigen (HAA) by the parallel use of three techniques: the complement fixation test, crossover-electrophoresis and immuno-electronmicroscopy.Out of a total of 204 persons investigated 63 (30.9%) were found to harbour the antigen. The HAA-positive sera originated almost exclusively from sporadic cases of acute viral hepatitis (clinically diagnosed as "infectious hepatitis" or "serum hepatitis"). The great majority of the hepatitis cases studied had a history of drug addiction.

Adolescent↗

[Rickettsia prowazekii polypeptide composition and protective antigens].

Serologically active preparations of R. prowazekii membranes were obtained by the lysis of purified R. prowazekii with ether and by differential and gradient centrifugation. Purified R. prowazekii and their membranes were analyzed by the method of electrophoresis in acrylamide gel. The former contained not less than 30 proteins with molecular weights of 10 000-169 000 daltons, while the membrane preparations contained 5 main polypeptides with molecular weights of 12400, 21500, 29600, 34000 and 133600 daltons. Antisera obtained after the immunization of rabbits with the membrane preparation were found to contain antibodies reacting in the complement fixation test and neutralizing rickettsial toxin.

Animals↗

[Rota virus infection in the newborn and infant -- epidemiological aspects (author's transl)].

In a total of 406 sera an age-dependent pattern of complement fixing antibodies against Rotavirus (Nebraska calf diarrhea virus) was found: 85% of the adults had antibodies, infants in the second half-year of life had the lowest percentage (42%). Thereupon a Rotavirus survey was carried out in a newborn ward by means of electron microscopy, enzyme-linked immunosorbent assay and complement fixation test during three weeks in January/February 1978. A chronically high infection rate was discovered. Children acquired intestinal infection despite of complement fixing serum antibodies and very few showed a rise in antibody titer.

Adolescent↗

Bovine leptospirosis: the effects of vaccination on serological responses as determined by complement fixation and microscopic agglutination tests.

Fifty-one calves were divided into six trial groups of seven to eleven animals and vaccinated with a commercial leptospiral vaccine containing serovars pomona and hardjo. Vaccinations were given at 6,7,14 or 21 months of age and animals in various groups were vaccinated on one to four occasions. Antibody responses were determined by the microscopic agglutination test (MAT) and the complement fixation test (CFT) at one to four weeks intervals until 66 weeks after the start of the trial. Fifty percent or greater agglutination in serum diluted 1:100 or more and 50% or greater fixation of complement in serum diluted 1:20 or more were considered positive titres in the MAT or CFI respectively. Positive titres were still present in some animals six weeks after vaccination at 21 months of age. In other cases MAT titres (range 1:100-1:3000) persisted for 7-23 weeks and CFI titres (range 1:20-1540) persisted for 1-14 weeks. Marked individual variation in serological findings occurred using either test. In general the number of animals producing a positive titre, and the magnitude and persistence of titres was related to the number of doses of vaccine given. It was concluded that for diagnostic purposes neither the CFT nor the MAT could reliably differentiate titres due to vaccination from those following natural infections.

Journal Article↗

THE ROLE OF DISULFIDE BONDS IN THE COMPLEMENT-FIXING AND PRECIPITATING PROPERTIES OF 7S RABBIT AND SHEEP ANTIBODIES.

The number of total disulfide bonds in rabbit and sheep 7S gamma globulin, before and after treatment with 2-mercaptoethanol, has been measured by amperometric titration. Mercaptan reduction could diminish the complement-fixing efficiency of 7S rabbit gamma globulin by no more than 90 per cent without any significant decrease in maximal complement-fixing ability. This was associated with the reduction of only 7 disulfide bonds, including 1 interchain disulfide bond [S-S((1))]. The reduction of 7 disulfide bonds in 7S sheep gamma globulin was associated with a 64 per cent decrease in complement-fixing efficiency, while reduction of 10 to 11 disulfide bonds decreased the complement-fixing efficiency by 90 per cent. Reduction of more disulfide bonds was not associated with any further decrease in complement-fixing efficiency, nor of any decrease in maximal complement-fixing ability. The reduction of more than 10 to 11 disulfide bonds in 7S rabbit and sheep gamma globulins was associated with a decrease in precipitating ability. The disulfide bonds which are more labile to mercaptan reduction appear to be associated with complement-fixing efficiency while the disulfide bonds which are more resistant to mercaptan reduction appear to be associated with precipitating ability. The measurement of interpolypeptide chain disulfide bonds has been discussed. One easily reduced interchain disulfide bond [S-S((1))] appears to be important for the complement-fixing efficiency of 7S rabbit antibody. The integrity of this same bond is essential for the precipitating ability of 5S rabbit antibody and may also be important for its complement-fixing ability.

Animals↗

Mycoplasma pneumoniae protein involved in the antibody response in human infection.

Antigen from purified Mycoplasma pneumoniae organisms treated with Tween-80-ether was used in a solid phase enzyme immunoassay and compared with the conventional lipid containing complement fixation antigen for measuring antibodies in sera from patients with aseptic or bacterial meningitis or with apparent M pneumoniae infection. In immunoblotting of the enzyme immunoassay antigen, enzyme immunoassay positive sera detected a polypeptide at Mr = 180.000-200.000, while enzyme immunoassay negative sera whether positive or negative in the complement fixation test did not. These results indicate that the enzyme immunoassay antigen containing the high molecular weight polypeptide can be used to measure M pneumoniae antibodies more specifically than the conventional lipid containing complement fixation antigen.

Antibody Formation↗

[Determination of antibodies to Campylobacter pylori in children and adolescents with gastroduodenal disorders].

Serological examination of antibodies against Campylobacter pylori was made in 195 boys and girls aged 9-20 years. In all on account of gastrointestinal complaints endoscopy was indicated. The results of microbiological and histological finding), in particular in the antrum and corpus of the stomach). Positive titres antrum and body of the stomach were compared with results of the complement fixation test and the ELISA reaction. Antibodies against C. pylori were detected in 64 of the examined subjects. The titres assessed by the complement fixation and ELISA test were in good agreement. Patients with positive sera had significantly more often a positive endoscopic finding (bacteria, chronic gastritis) and bacteriological finding), in particular in the antrum and corpus of the stomach). Positive titres of the complement fixation reaction persisted frequently for 15 months after the first examination. From the results ensues that serological examination of antibodies against C. pylori can be considered a sparing examination method which in patients with gastrointestinal complaints should precede endoscopic examination and moreover it can be used to follow up the course of the disease and success of therapy.

Adolescent↗