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Results for “Complement Fixation Tests”
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A modified complement fixation test that is subject to minimal anti-complementary activity by sheep serum.
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[New human polyomavirus: comparison of hemagglutination inhibition, ELISA and complement fixation tests for BK virus serology].
In this study, 110 sera samples taken from healthy persons were tested for BK virus antibodies by using hemagglutination inhibition (HI), ELISA and complement fixation (CF) tests to detect the sensitivity, specificity and agreement of these tests. The results of each individual test was compared with others for sensitivity and specificity. Specificity found to be 96% when HI and CF tests were compared. Sensitivity also found to be 92.7% when CF and ELISA tests were compared. Agreement of HI and ELISA tests were 88%.
Evaluation of an enzyme-linked immunosorbent assay (ELISA) for the detection of Campylobacter jejuni antibodies, and comparison with a complement fixation test (CFT).
An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of total anti-Campylobacter immunoglobulins in human sera. In this assay disintegrated Campylobacter bacteria were used as the antigen. Absorption tests including other possibly enteropathogenic bacterial species showed that the ELISA system displayed a high immunological specificity for Campylobacter. Using this ELISA it was found that in about 80% of Campylobacter patients these Campylobacter antibodies are produced to almost maximal levels within 8 days after onset of disease, and that they may persist for at least 4 months. Indeed, Campylobacter antibodies were demonstrated at low levels in a large number of control sera. However, accepting an antibody titre of 1:640 as indicative of Campylobacter infection, the statistical sensitivity of the ELISA system was 77% and the specificity 95%. In an epidemiological survey a high association was demonstrated between the severity of Campylobacter-related symptoms and antibody titre values. Assessment of Campylobacter antibody titres by means of this ELISA and by a complement fixation test in 92 sera from index patients and contacts with and without symptoms showed a high association of results.
Methods of preparing supplementing fractions from fresh unheated bovine sera for use in modified direct complement-fixation tests.
TWO METHODS OF PREPARING PARTIALLY PURIFIED, RELATIVELY STABLE SUPPLEMENTING FACTOR FROM FRESH BOVINE SERUM ARE DESCRIBED: gel filtration through Sephadex G-25, and anion exchange chromatography on a diethylaminoethyl (DEAE) cellulose column. In both procedures, an active, reconstituted precipitate prepared by dialysis of fresh unheated normal serum in the cold for 18 hours against phosphate buffer pH 6.2, 0.02 M, serves as the starting material. The Sephadex G-25 column is equilibrated with acetate buffer pH 5.4, 0.2 M. The most actively-supplementing material appears in the eluates in which the pH has risen to 7.5 or higher. For the DEAE cellulose chromatography a gradient system is used: initial phosphate buffer 0.03 M, pH 8.0, limiting buffer Na H(2)PO(4), 0.3 M. The greater part of the supplementing activity is eluated between pH 5.6 and 6.0, although some of the earlier fractions are also reactive. Pooled active eluates stored in the frozen state for nine months or longer maintained their supplementing titre in modified complement-fixation tests of two bacterial antigen-bovine antibody systems.
Single radial complement fixation test using NP-containing plates: a simple and sensitive method for the detection of influenza infection.
The single radial complement fixation (SRCF) test using nucleoprotein (NP) was compared with the haemagglutination inhibition (HAI) test in the course of the evaluation of the protective efficacy of influenza vaccine. In the case of persons who were not vaccinated, the percent incidence of infection was almost the same (which confirmed by HAI test or by SRCF test), whereas in the case of vaccinees, there was a significant difference between the incidence confirmed by HAI (7.9%) and SRCF (19.4%) tests. The SRCF test was shown to be a simple and sensitive method for detection of a significant rise in antibody titre against influenza virus.
Increased sensitivity of the complement fixation test for contagious bovine pleuropneumonia on sera preserved with phenol.
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Complement fixation tests for equine piroplasmosis (Babesia equi and B caballi) performed in the UK during 1976 to 1979.
The results of complement fixation (CF) test for equine piroplasmosis on sera from horses destined for international movement from Great Britain and Ireland are presented and analysed. No horses born and continuously resident in the British Isles were found carrying CF antibodies to either Babesia equi or B caballi. Positive animals were found to have association with the following countries where known tick vectors occur: Spain, Portugal, Belgium, France, Poland, USSR and Arabian Gulf countries. Data on the persistence of CF antibodies in animals subjected to repeated testing showed that some animals lost their CF titre within a few months of their first test while others retained a titre for periods up to 13 months of B caballi and 28 months for B equi. Some individuals regained titres on subsequent tests after becoming negative and the results suggest that removal from exposure to infection or, even, treatment does not necessarily eliminate a CF titre within a predictable time limit.
[Immunological studies of aortitis syndrome. (1) Complement fixation test and precipitation test].
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[Determination of the hepatitis B antigen (HBAg) by the complement fixation test using the auto analyzer (author's transl)].
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A complement fixation test for the serological diagnosis of leptospirosis in pigs experimentally infected with serotype Pomona.
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The micro-complement fixation test. I. A solution of the technical problems of HL-A typing?
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Complement fixation test of equine infectious anemia. I. Specificity of the test.
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Evaluation of micro complement fixation tests for antibodies against group A streptococcal M and M-associated antigens in rabbit and human sera.
Variables involved in micro complement fixation (CF) tests for type-specific (TSM) and non-type-specific (NTSM) antibodies against preparations of streptococcal M protein were studied. Sera of rabbits immunized with purified M protein which contained high titers of anti-TSM and low titers of anti-NTSM antibodies reacted type specifically in the CF tests when relatively low concentrations of M protein were employed. In contrast to these artificially induced TSM antibody responses, the sera of rheumatic fever patients demonstrated elevated CF antibody titers (1:80 to 1:320) in the presence of both high and low concentrations of M antigen. The CF test cannot distinguish TSM and NTSM antibodies when the latter predominate. The CF test can be employed with confidence for the detection of NTSM antibodies, provided that the test sera are known to lack type-specific antibodies against the M protein used in the test.
New complement-fixation test for the human reovirus-like agent of infantile gastroenteritis. Nebraska calf diarrhea virus used as antigen.
A complement-fixation (C.F.) test for the human reovirus-like agent of infantile gastroenteritis has been developed using the serologically related Nebraska calf diarrhoea virus (N.C.D.V.) as antigen. Most infants and children who shed the agent in stools and/or who demonstrated serological (C.F.) evidence of infection with a reovirus-like-particle-positive human stool-filtrate C.F. antigen also demonstrated serological evidence of infection when a concentrated N.C.D.V. preparation was employed AS C.F. antigen. The N.C.D.V., which was previously shown to be related to the human reovirus-like agent, was found to be related antigenically to the epizootic diarrhoea of infant mice (E.D.I.M.) virus also. Studies on the prevalence of C.F. antibody in sera from infants and young children revealed a pattern of rapid acquisition of antibody to both the human reovirus-like agent and the N.C.D.V. as over 80 percent of these individuals possessed antibody to each agent by 36 months of age. A strong positive association was found in the results obtained with the two antigens. The ready availability of cell-culture grown N.C.D.V., and its ability to serve as a "substitute" C.F. antigen for the human reovirus-like agent, should enable the serodiagnosis of many cases of disease due to the human agent and facilitate seroepidemiological studies of such infections. In addition, the observation that a large proportion of individuals infected with the human reovirus-like agent develop serological evidence of infection not only to the human agent but to the calf agent as well may have important implications in the immunoprophylaxis of disease caused by the human reovirus-like agent.
[Determination of antibody kinetics in Mediterranean spotted fever using the Weil-Felix agglutination test, complement fixation and indirect immunofluorescence].
The kinetics of antibodies in human cases of Mediterranean spotted fever was studied by applying Weil-Felix (WF) agglutination with Proteus OX antigens, complement fixation (CF) and indirect immunofluorescence (IF) tests with Rickettsia conorri antigen to 46 sera from 21 patients. The kinetics of specific (CF and IF) and nonspecific (WF) antibodies was similar. The percentage of the positive sera and geometric mean titers of antibodies reached the maximum after 14 days from the onset of illness.
Field validation of the use of RB51 as antigen in a complement fixation test to identify calves vaccinated with Brucella abortus RB51.
In order to confirm the efficiency of an experimental RB51-based complement fixation (CF) test in identifying cattle vaccinated with Brucella abortus strain RB51, 831 sera from 110 vaccinated and 48 unvaccinated Hereford heifers of Iowa, collected for studies conducted in different years, were sent to Italy without coding to be tested in a CF test using RB51 as antigen. Most of the calves, aged from 3 to 10 months, were vaccinated subcutaneously with the recommended dosage of 10(10) CFU of RB51 commercial vaccine, while only six calves received 10(9) CFU of the same vaccine. Serum samples for serologic testing, collected until 16 postinoculation weeks (PIW), were also tested by routine surveillance tests for brucellosis such as rose bengal plate and CF tests performed with B. abortus smooth strain 99 as control antigen. RB51 CF test results obtained by testing sera from cattle vaccinated in 1999 indicate that the sensitivity of the reaction is 97% at 2 to 3 PIW and 90% until 8 PIW and decreases to 65% at 12 PIW, the specificity remaining at 100%. Collectively, the results of this study confirm that serologic standard tests fail to detect antibodies to RB51 while the RB51-based CF test is able to monitor antibody responses to RB51 until 15 to 16 PIW with a specificity of 100%. In addition, unlike the RB51-based dot blot assay, which is the only test currently used to monitor antibody responses to RB51, the CF test also detected specific responses following vaccination with 10(9) CFU of RB51, although seroconversion was only 50% at 8 PIW. In conclusion, because of high specificity and sensitivity, the CF test described here can be used to efficaciously monitor serologic responses following RB51 vaccination in cattle and could also be employed to detect RB51 infection in humans exposed to this strain.
Comparison of seroreactivity of rams with brucellosis in a complement fixation test, whole cell ELISA and by immunoblotting.
In rams with ovine brucellosis, a high degree of serological correlation exists between the complement fixation (CF) test which utilises antigen extracted from bacteria with hot saline, and the ELISA reactivity using methanol-fixed Brucella ovis as the assay reagent. Since the whole cell ELISA (CELISA) detects mainly antibodies against surface antigens of B. ovis, it was concluded that the similar findings of the two serological tests is due in part to the presence of membrane antigens in the CF test antigen following hot saline extraction of intact bacteria. Immunoblots with pooled sera representing different CF titres confirmed that the major immunoreactive antigens of B. ovis were located in four zones: alpha, beta, gamma 1 and 2 with corresponding apparent molecular masses of 55 and 60 kDa; 27 and 29 kDa; 18.5-20 kDa and 17-18 kDa, respectively. These zones of reactivity were consistently present in immunoblots when assayed against different B. ovis isolates even though Coomassie brilliant blue staining of SDS-PAGE gels revealed some differences in polypeptide banding patterns. However, these intensely-stained CBB bands located at 38 and 40 kDa which distinguished three of the seven B. ovis isolates were considerably less reactive in immunoblots compared to polypeptides that were located at positions equivalent to alpha, beta or gamma reactivities. Intensity of immunoblot reactivity against polypeptides located in the alpha, beta and gamma zones intensified with increasing CF titre. Sera with CF titres greater than 32 also tended to react against bands of higher apparent molecular masses located at 65, 70, 73, 78, 80 and 86 kDa.(ABSTRACT TRUNCATED AT 250 WORDS)