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Field evaluation of a microtitration complement-fixation test for diagnosis of Mycoplasma gallisepticum in chickens.

Results of a direct microtitration complement-fixation (CF) test were compared with hemagglutination-inhibition (HI) test results in diagnosing Mycoplasma gallisepticum (MG) infection of chickens in the field. Of 16 flocks negative for MG by the HI test, eight were CF-positive. Of nine flocks that were HI-positive for MG, three were CF-negative. It was concluded that the CF test is not effective in diagnosing MG infection of chickens in the field.

Animals↗

[Standardization of the complement fixation test (CFT) in brucellosis. I. The Polish standard of anti-Brucella abortus serum].

The purpose of this paper was to prepare an indigenous standard of anti-Brucella abortus serum for the complement fixation test (CFT) as a homologue of the secon International Standard of anti-Brucella abortus Serum (ISABS-II), which contains 1000 international units of complement-fixing antibodies in 1 cm3. The indigenous Standard of anti-Brucella Abortus Serum (ISABAS) was prepared in 1975. The material used was the serum of a cow infected with Br.abortus, biotype 1, under natural conditions. The cow was beheaded on the 54th day after abortion. The serum obtained was filtered through a Seitz EK filter and appropriately diluted with normal bovine serum. The preparation was lyophilized in 8500 ampules, each of which contained 1 cm3 of serum. They were filled with nitrogen before closing them. It was shown that ISABAS activity in CFT was approximate to that of ISABS-II. The studies in CVL, Weybridge showed that one ampule contained 1115 international units of complement-fixing antibodies. ISABAS titres in the agglutination test (AT) and antiglobulin test (AGT) were 320+ + and 2560+ + + respectively. Reduction with 2-mercaptoethanol and separation on a column with Sephadex G-200 gel showed that anti-Brucella antibodies occurred in ISABAS mainly in IgG class. ISABAS lyophilizate is characterized by stability of CFT titre, good solubility and a low anticomplementary activity. The average weight of the lyophilizate in an ampule is 79.57 mg, standard deviation - 0.36%. ISABS may serve as the basis of antigen standardization and other elements of indigenous CFT technique in brucellosis.

Animals↗

Comparison of enzyme-linked immunosorbent assay (ELISA) and complement fixation test for detection of Mycoplasma pneumoniae antibodies.

An enzyme-linked immunosorbent assay (ELISA) for the detection of IgG and IgM antibodies against Mycoplasma pneumoniae, performed with commercial antigen and reagents, is compared with the complement fixation test (CF) in a serological study of 209 human sera. Concordant results were usually obtained by CF test and by IgG ELISA in sera from patients with recent M pneumoniae infection. In contrast, when used for an immunological survey of a general population, approximately 27% of the sera negative in the CF test were positive for IgG by the ELISA, and sera with low CF titres were found to have a broad range of IgG titre by the ELISA. This may be due to the greater sensitivity of the ELISA technique and/or to different types of antibody measured by both tests. IgM was detected by ELISA in sera from all patients with recent M pneumoniae infection diagnosed on the basis of clinical findings and by CF assay. Occasionally false-positive IgM antibodies were due to rheumatoid factor (RF); this potential interference necessitates routine testing of IgM antibody positive sera for RF.

Adult↗

The complement-fixation test in the diagnosis of congenital toxoplasmosis.

We present serologic results on 26 patients with congenital toxoplasmosis and on 22 of their mothers. The infection was severe (central nervous system involvement) in 12 patients, 12 had only ocular manifestations, and two were asymptomatic. The dye test results were positive on all specimens, and were positive at a titer of 1:1,024 or higher if collected from patients younger than 2 years of age. The complement-fixation test (CFT) results were positive on all specimens from patients younger than 2 years of age and on 69% of specimens collected from older patients. These serologic results are contrasted with those obtained on two control groups: (1) 46 uninfected infants followed up after birth because of substantial antibody titers in their mothers during pregnancy; and (2) 190 infants and children tested because toxoplasmosis was tentatively included in the differential diagnosis of the current illness. In both control groups the positive results on the CFT were limited almost exclusively to cord blood specimens or specimens collected during the first 2 weeks of life. Lower CFT titers in follow-up specimens suggested that the antibodies were maternal in origin. These two tests are valuable in providing laboratory support for the diagnosis of congenital toxoplasmosis, particularly the test for the comparatively short-lived complement-fixing antibody.

Antibodies↗

Antigenic relationship between human and bovine rotaviruses as determined by neutralization, immune adherence hemagglutination, and complement fixation tests.

Guinea pig antiserum to bovine rotavirus does not neutralize human rotavirus. Bovine and human rotaviruses were, however, extensively cross-reactive when examined by complement fixation and immune adherence hemagglutination tests with antiserum to either virus. The immune adherence hemagglutination test was 16- to 32-fold more sensitive than the complement fixation test in detecting rotavirus.

Animals↗

The potency determination of human varicella-zoster immunoglobulin by enzyme-linked immunosorbent assay, complement-fixation test and indirect fluorescent antibody tests.

Traditionally, plasma for the production of the human varicella-zoster immunoglobulin (VZIG) has been selected on the basis of the complement-fixing antibody (CFA) titre. Since immune individuals may lack CFA to varicella-zoster virus (VZV), non-CFA may be of importance in protection. In a search for a simple and reliable method for potency determination, 24 VZIG preparations were quantified by enzyme-linked immunosorbent assay (ELISA), the complement-fixation test (CFT), the indirect fluorescent antibody test to acetone-fixed (IF) and viable (FAMA) VZV-infected cells, respectively. The antibody titres obtained by the various methods were compared. Arranged in order of decreasing agreement, the correlation coefficients (r) of the regression equations between the variables were 0.62 for CFT and FAMA, 0.50 for CFT and ELISA and 0.26 for CFT and IF in a log2 plot. There was complete agreement between the titres obtained by the commercially available Enzygnost Varicella/Zoster kits (Behring Institute, Marburg, F.R. Germany) and the ELISA microtitre plates produced at our institute (r = 1). The regression equation lines for ELISA/CFT and FAMA/CFT titres tended to be parallel to each other, while the line for IF/CFT titres had a less steep slope. Similar titration curves were obtained for VZIGs fractionated by two different methods. Furthermore, the titration curves of serum pools from varicella and zoster convalescents, respectively, had a similar shape below delta OD = 0.4. Generally, a steeper slope was observed above delta OD = 0.4. As antibody detectable by ELISA seems to correlate with protection and the method is sensitive, specific, reproduceable, simple to carry out and easily automated, it may be suitable for the potency determination of VZIGs.

Antibodies, Viral↗

Detection of Campylobacter pyloridis in patients with antrum gastritis and peptic ulcers by culture, complement fixation test, and immunoblot.

The association of Campylobacter pyloridis with antrum gastritis and peptic ulcers was described. We investigated antral biopsies from 180 patients who underwent gastroscopy. By culture or Gram stain or both, we found overall 98 (54%) of them to be positive for C. pyloridis. In the various groups the following percentages were found to be positive: normal antral mucosa 3% (n = 30); moderate superficial antrum gastritis, 49% (n = 83); severe superficial antrum gastritis, 86% (n = 44); duodenal ulcer, 83% (n = 54); and gastric ulcer, 72% (n = 18). A serological screening that used a complement fixation test yielded the following results: highest rates of positive complement fixation titers were seen in patients with severe gastritis and those with duodenal ulcers, both with 79%; the lowest incidence was in a group of 20 blood donors, with 5%. Positive complement fixation titers in gastritis patients also correlated well with characteristic patterns on immunoglobulin G and A immunoblots, while there was no specific reactivity observed on immunoglobulin M immunoblots.

Antibodies, Bacterial↗