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PubMed1988

[The role of Mycoplasma pneumoniae in acute pneumopathies in children].

Among 199 cases of bronchopulmonary infection in children observed over a 2-year period, 22 cases (11%) were due to Mycoplasma pneumoniae. The diagnosis was based upon the complement fixation test on whole serum in half of the children and the research of specific IgM by complement fixation test on fractioned serum and/or indirect immunofluorescence on the others. The mean age of children with Mycoplasma pneumoniae was 6 years. The clinical and radiographic appearance of the affection was non specific, often similar to pneumococcal pneumonia.

Acute Disease↗
PubMed1982

Chlamydia trachomatis: serological diagnosis.

Satisfactory methods for the serodiagnosis of Chlamydia trachomatis have been widely discussed in recent years. Until a decade ago, the complement-fixation test measuring group-specific antibody was the most widely applied technique. However, despite showing relatively high diagnostic sensitivity in systemic chlamydial infections, it is of little value in the serodiagnosis of localized chlamydial oculo-genital infections or of trachoma. The more recently developed microimmunofluorescence (micro-IF) test is not only a very sensitive technique, but can also reach a high degree of serodiagnostic specificity in certain chlamydial infections. Unlike the complement-fixation test, it measures type-specific antibody which may be directed against one or more C trachomatis serotypes. By nature, chlamydia infections often lead to high background rates of antibody in affected populations. Interpretation of serological results may therefore be difficult, particularly when only single-serum samples are available. However, in seroepidemiological work, in the study of transmission patterns and in the detection of predominant serotypes in a community, the micro-IF test is especially valuable, and if results are interpreted with care, the test may also serve as an indicator of chlamydial infection. The predictability, sensitivity and specificity of serological tests for C. trachomatis will be discussed.

Antibodies, Bacterial↗
PubMed1979

[Antibodies against Chlamydia trachomatis in patients with non-gonococcal urethritis and in the healthy Italian population].

The Authors report the results of a study on the prevalence of serum antibodies against Chlamydia trachomatis among patients with non-gonococcal urethritis caused by Chlamydia trachomatis and diagnosed on the basis of the isolation of the microorganism in cell cultures, among patients with non-gonococcal urethritis of unknown etiology and in groups of healthy population, in Italy. The search for antibodies was performed both with complement-fixation tests in micro-titer system, using an antigen prepared from chicken embryo yolk sacs infected with the 6BC strain of Chlamydia psittaci, and with indirect immunofluorescence tests. The indirect immunofluorescence tests were carried out using as antigen the whole chlamydial inclusion developed in IUDR pre-treated McCoy cell cultures, grown on coverslips, and infected with the BU/434 strain of the LGV2 immunotype of Chlamydia trachomatis. The immunofluorescence tests proved to be much more sensitive than the complement fixation tests in detecting the presence of anti-chlamydial antibody both in patients with non-gonococcal urethritis and in the healthy population groups. The percentage of subjects possessing anti-chlamydial antibodies among the healthy population suggests a diffuse circulation of Chlamydia trachomatis infection. The possibility of employing the serological data in the diagnosis of the etiology of non-gonococcal urethritis is briefly discussed.

Adolescent↗
PubMed1976

Acute enteritis associated with reovirus-like agents.

In Atlanta, from January to April 1975, reovirus-like agents (RLAs) were detected by a simplified electron-microscopic technique in the stools of 16 of 29 children with acute enteritis. Complement fixation tests with purified RLA antigens demonstrated antibody titer rises in seven children with RLA in their stools and in two mothers (one symptomatic) from whom acute and convalescent sera were available. Complement fixation tests performed on 207 individuals of varying ages and 60 laboratory workers indicated a high frequency of past infection with RLA, the highest frequency being in children 6 months to 4 years of age. These results corroborate the high rate of RLA detection in the stools of children with acute enteritis in other parts of the world and suggest that such infections can also occur in adults.

Acute Disease↗
PubMed1975

[Diagnosis of Johne's disease].

The authors carried out clinical observations and allergical, bacteriological and serological investigations of 73 dairy cows in a herd affected with paratuberculosis. Durings 18 months, clinical signs of the disease were noted in 2 animals only. It was found that the allergic test with the use of johnin had a limited diagnostic value and made it possible only to suspect the disease in the herd. Avian tuberculin had higher potency than johnin and gave, in most cases, stronger allergic reactions in animals infected with M. johnei that the homologous preparation. Bacterioscopic and cultural examination of the faeces with the use of Stuart's serum-agar medium had a significant diagnostic value because they made it possible to detect the excretion of Johne's bacilli before the clinical signs could be observed. The complement fixation test gave positive results in animals with the clinical symptoms of the disease, or when pathological lesions in the intestines were pronounced. In most of the cows investigated, the pathological changes of the ileocecal valve, characteristic for paratuberculosis, appeared earlier than the positive results of the complement fixation test.

Animals↗
PubMed1976

Rat adrenal dopamine-beta-hydroxylase: purification and immunologic characteristics.

Dopamine-beta-hydroxylase (DBH) was purified from rat adrenal medulla by a series of steps including sedimentation of membranes, extraction with n-butanol, ammonium sulfate fractionation, gel chromatography and ion-exchange chromatography. Disk gel electrophoresis revealed two protein bands, both of which were active. Antiserum was prepared against homogeneously purified bovine adrenal and rat adrenal DBH; Ouchterlony immunodiffusion, enzyme neutralization and complement fixation tests demonstrated that the respective homologous antisera were monospecific and of high titer. Antiserum to bovine DBH was only 2- to 3-fold more potent than pre-immune serum in inhibition of rat DBH activity. Complement fixation tests demonstrate that antiserum to bovine DBH has a 25,000-fold lower immunoreactivity with rat DBH than with bovine DBH.

Adrenal Glands↗
PubMed1985

Screening tests for antibodies to cytomegalovirus: an evaluation of five commercial products.

Four hundred and ninety two samples of serum from blood donors were screened for the presence of antibodies specific to cytomegalovirus using radioimmunoassay, a modified complement fixation test, and five commercially available tests: the Cetus CMV IHA, Abbott CMV total AB EIA, Cytomegalisa Stat EIA, Enzygnost EIA, and Virenz G-CMV EIA. A wide variation in results was found, with only 53.5% of the sera giving total concordance by all methods. Rates of seropositivity in the different tests ranged from 34.9% to 59.3%, with sensitivities ranging from 75.2% to 99.1% compared with the radioimmunoassay. Of 211 sera which gave positive results with four or more of the tests, none was negative by the radioimmunoassay and Abbott EIA, three were negative in Cetus IHA and Enzygnost EIA, and 11 were negative in the modified complement fixation test. Virenz G and Cytomegalisa Stat EIAs, however, gave 40 (19%) and 49 (23.2%), respectively, as negative. The results confirmed the reliability of the radioimmunoassay for the detection of the antibody status to CMV, but this test is too elaborate for a screening procedure. The Abbott EIA and Cetus IHA were found to be the most suitable for this purpose in spite of high false positive rates.

Antibodies, Viral↗
PubMed1995

[Evaluation of conventional and new generation tests for testing the humeral response to Mycoplasma pneumoniae antigens in natural infection in humans. III Use of ELISA, complement fixation and immunoelectroprecipitation tests in diagnosis of Mycoplasma pneumoniae infections--comparative analysis].

Agreement of the results of determining antibodies against M. pneumoniae was evaluated by the ELISA, complement fixation test (CFT) and immunoelectroprecipitation test (IEPT) in serum samples from 685 persons including 571 patients with respiratory tract infections and 114 clinically healthy subjects. Assuming the CF to be the reference test, a very high correlation exceeding 0.95 was found, on the basis of the calculated correlation coefficient, between the results of the CF and IEP tests and the CFT and ELISA in all immunoglobulin classes. The highest sensitivity (92.3%) was displayed by the ELISA in relation to the CF test when determining mycoplasmas antibodies of IgM and IgA + G + M classes and slightly lower sensitivity by the IEPT and ELISA when determining of IgG (83% and 82.1% respectively). The lowest sensitivity was displayed by the ELISA when determining mycoplasmal antibodies of IgA class (53.4%). Specificity of both the tests was high and exceeded 92%. Highest agreement of CFT and ELISA was obtained when detecting mycoplasmal antibodies in diagnostically significant titer in the M and A + G + M immunoglobulin classes (> 92%) while lowest agreement, although statistically significant, was obtained when detecting IgA antibodies (74.7%).

Adolescent↗
PubMed1984

Characterization of Barmah forest virus: an alphavirus with some unusual properties.

Barmah Forest virus has been characterized in a number of ways including electron microscopy of infected cells; physical studies of the virion, its RNA, and associated proteins; N-terminal sequence analysis of the two envelope glycoproteins; studies of macromolecular species present in infected cells; and serological cross-reactions with alphaviruses and bunyaviruses. From these results Barmah Forest virus is clearly an alphavirus since the structure of the virion, the mode of replication, and the macromolecular species present in infected cells are typical of alphaviruses. The N-terminal regions of the two glycoproteins E1 and E2 show extensive sequence homology (approximately 50%) with those of other alphaviruses. Barmah Forest virus cross-reacts in hemagglutination inhibition tests, although not in complement fixation tests or infectivity neutralization tests, with other alphaviruses. In some of its properties Barmah Forest virus is unusual, however. It cross-reacts in complement fixation and hemagglutination inhibition tests with Umbre virus, a bunyavirus, which originally led it to be classified as a bunyavirus; the glycosylation pattern of E2 of Barmah Forest virus appears to differ from that of other alphaviruses; and the sedimentation coefficient of the virion appears to be slightly less than that of other alphaviruses.

Aedes↗
PubMed1981

Diffusion-in-gel enzyme linked immunosorbent assay (DIG-ELISA) for detection of antibodies to Yersinia enterocolitica O:3.

The Diffusion-In-Gel Enzyme Linked Immunosorbent Assay (DIG-ELISA) is a new and simple method for the quantitation of antibodies to diffuse from wells in gel in petri dishes and absorb to an antigen coated to the plastic surface prior to testing. The antigen-antibody reaction is visualized with horseradish-peroxidase conjugated class-specific anti-immunoglobulins. The DIG-ELISA permits detection of 0.1 microns/ml of specific antibodies. This method was used to determine the IgG, IgA and IgM antibody levels to Yersinia enterocolitica O:3 in sera from patients with antibody titres to this microorganism, as determined by direct agglutination and complement-fixation test. The DIG-ELISA IgG antibody values, in contrast to IgA and IgM, correlated well to titres obtained by the direct agglutination method. Low degrees of correlations were found for all three immunoglobulin classes when compared to the complement fixation test.

Antibodies, Bacterial↗
PubMed1984

Solid-phase radioimmunoassay for the detection of immunoglobulins against bovine Brucella abortus.

A sensitive radioimmunoassay for the detection of Brucella abortus antibody is described. The assay, performed in flexible 96-well microplates coated with Brucella abortus antigens, utilizes 125I-labeled staphylococcal protein A to detect antibody to Brucella abortus. The parameters of the assay have been analyzed using well recognized statistical methods. Least squares analysis of antigen concentration, antiserum dilution, antigen by antiserum and replicates within antigen by antiserum, estimated an r2 of 0.98, a coefficient of variation of 3.58 and a standard deviation of 0.10. Results of regression analysis of serum dilution versus antigen concentration (ranging from 635 micrograms/ml to 6.35 ng/ml) indicated that an antigen concentration of 6.35 micrograms/ml was the most efficient for describing antibody variability (r2 = 0.98, with a coefficient of variation = 3.28). Regression analysis also revealed a closer correlation between the radioimmunoassay with complement fixation test (r2 = 0.98) than with the standard tube test (r2 = 0.84). Detection of specific antibody assessed by radioimmunoassay was 4 to 64 fold more sensitive than the standard tube test titer and 16 to 32 fold more sensitive than the complement fixation test titer. The results described here indicate that this radioimmunoassay is very sensitive and may be capable of discriminating between false positives and false negatives, thereby, improving the diagnostic efficiency of Brucella serologic tests.

Animals↗
PubMed1980

Evaluation of a radial immunodiffusion test with polysaccharide B antigen for diagnosis of bovine brucellosis.

A radial immunodiffusion (RID) test employing a polysaccharide antigen (poly B) was compared with tests currently used in the diagnosis of bovine brucellosis. Over 1,000 sera from vaccinated and infected cattle, all of which had been examined bacteriologically, were used to determine the sensitivity and specificity of the RID, card, Rivanol, and complement fixation tests. The RID test identified 90% of the cattle that were shedding Brucella in their milk. Although the complement fixation test was more sensitive, it was less specific than the RID test in cattle vaccinated as adults with Brucella abortus strain 19. A sensitive screening test, such as the card test, in combination with the RID test could be used in diagnostic laboratories, or even in the field, with little additional expense or technical expertise. An additional advantage is that the RID could be applied to sera from adult cattle as early as 2 months after vaccination, when postvaccinal agglutinins and complement-fixing antibodies may still be present. The indirect hemolytic test was used with some of the sera and was found to be a very sensitive test which could be useful in areas of low incidence but would not be practical for large-scale testing in adult-vaccinated herds.

Animals↗
PubMed1971

Characterization of an equine infectious anemia antigen extracted from infected horse spleen tissue.

The spleens of horses infected with equine infectious anemia contain an antigen that is useful for a diagnostic immunodiffusion test. This antigen was extracted from the spleen by homogenization of the tissue, centrifugation, and precipitation from the supernatant fluid at 50% saturation with (NH(4))(2)SO(4). The antigen was purified by subjecting it to two cycles of electrophoresis in a continuous free-flow electrophoresis cell and finally filtering through a column of Sephadex G-200 gel. The antigen was found to be a small protein with a molecular weight of 27,500 and sedimentation coefficient of 2.1S. Its density was about 1.18 and its isoelectric point 5.8. At 45 to 50 C, it coagulated, losing its antigenicity. The antigen was useful for assaying antibody in the serum from infected horses by using the complement fixation test or the immunodiffusion test. Complement-fixing antibodies were found to be more transient than the precipitating antibodies.

Animals↗
PubMed1967

Serological comparison of spherules and arthrospores of Coccidioides immitis.

Spherule and arthrospore cellular preparations were sonic-treated and separated into their respective supernatant and sediment components. Complement-fixation tests with antispherule and antiarthrospore pooled rabbit sera revealed that the soluble antigens exhibited more serological activity than the sediment preparations. After autoclaving, an arthrospore cellular antigen exhibited increased activity with either antisera, whereas autoclaved spherules exhibited increased activity only with antispherule serum. Complement-fixation tests with coccicioidin and spherule culture supernatant preparations revealed quantitative or qualitative differences in antigenic determinants between these two morphological phases of Coccidioides immitis.

Antigen-Antibody Reactions↗
PubMed1983

[Effect of routes and doses of Salmonella abortus ovis inoculation on the abortive effect and serologic response of ewes].

Three successive experiments using a restricted number of Préalpes X Lacaune ewes were designed to form a procedure allowing the reproduction of an abortive infection with Salmonella abortus ovis. Effects of inoculations at mid-gestation were estimated by the duration of gestation, bacteriological excretion at lambing and evolutions of rectal temperatures and of serological antibodies. Serological responses were revealed with four tests: O or H agglutination tests in tubes, H agglutination or complement fixation tests in microtechnics. Intravenous inoculations of 10(9) salmonella induced lethal septicaemia. Intragastric inoculations of 10(7), 10(8), 10(9) or 10(10) salmonella did not produce effects related to inoculated doses; in particular the only abortion obtained in this way occurred after inoculation of 10(7) salmonella. Subcutaneous inoculation of 10(6) to 10(10) salmonella induced serological, bacteriological and clinical responses related to the inoculated doses: ewes with at least two febrile phases during the 20 days post-inoculation aborted, including two ewes not excreting salmonella at lambing. After intragastric or subcutaneous inoculation, and with the four serological tests, the initial raising of titers was followed by an early and rapid decrease, without a new rise round about the time of abortion; no salmonella was isolated from ewes autopsied three to six months after inoculation. It appeared that the subcutaneous inoculation of 10(10) S. abortus ovis viable to ewes at mid-gestation was able to frequently induce a sublethal but abortive infection.

Abortion, Veterinary↗
PubMed1985

[Varicella-zoster virus infection and the serologic determination of first-infection immunity].

The infection rate of varicella-zoster virus was determined by three tests--complement fixation reaction, enzyme-immune test and indirect immunofluorescence. The results of the three tests largely agreed with one another in demonstrating that infection starts relatively late in young children, but reaches 60%-70% at the end of the first decade of life, 90% at the end of the second decade. Results of both the enzyme immune and the indirect immunofluorescence tests indicated persistence of first-infection immunity until the older age groups. The complement fixation reaction deviated in its results, especially for the oldest age groups.

Antibodies, Viral↗
PubMed1977

Sensitive enzyme-linked immunosorbent assay for detection of antibodies against typhus rickettsiae, Rickettsia prowazekii and Rickettsia typhi.

An enzyme-linked immunosorbent assay (ELISA) has been developed for the titration of rickettsial antibodies in human and animal sera. Two preparations of soluble typhus-group antigens were obtained from Rickettsia typhi and Rickettsia prowazekii by ether extraction: a standard antigen from infected yolk sacs (YS antigen) and one free of yolk sac contaminants from Renografin-purified rickettsiae (PR antigen). Rabbit, mouse, and guinea pig sera were obtained by immunization with viable purified R. typhi or R. prowazekii. Human sera were obtained from individuals who had recovered from laboratory infections with either typhus rickettsia months or years previously. Goat-derived anti-immunoglobulins were conjugated to alkaline phosphatase with glutaraldehyde. Although the PR and YS antigens gave equivalent antibody titers in the complement fixation test, the PR antigen was clearly superior in the ELISA. With this antigen, the titration curves of all antisera were linear over a wider range of serum concentrations and the titers were higher than with the YS antigen. With YS and PR antigens, ELISA titers were higher than those obtained by complement fixation by one and two orders of magnitude, respectively. In human sera, immunoglobulin G and immunoglobulin M antibodies were demonstrated by their respective anti-immunoglobulins and by differential susceptibility to ethanethiol. ELISA titers showed some type specificity, whereas none was observed in complement fixation tests. The ELISA is highly sensitive, reproducible, and easily adaptable to the various requirements of clinical and research laboratories.

Animals↗