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Diagnosis of bovine respiratory syncytial virus infection by complement fixation test.

The complement fixation test by the microtiter method was applied to the serological diagnosis of bovine respiratory syncytial (RS) virus infection. When used as complement fixing antigens, untreated infected cell culture fluid, fluorocarbon-treated, and ether-treated materials showed no differences in antigenicity among them. The complement fixing antigenicity of bovine RS virus appeared in bovine kidney and Vero cell cultures for the first time 4 days after inoculation. Both the infectivity and complement fixing antigenicity reached a maximum 6 days after inoculation. In detecting complement fixing antibody from infected cattle, the most outstanding specific reaction was obtained when 5% fresh normal calf serum had been added to the diluent of complement. Neutralizing and complement fixing antibodies were examined in serum samples from two cattle in the course of experimental infection. It was found that both antibodies turned to be positive 2 weeks after inoculation. There was a linear correlation between neutralizing and complement fixing antibody titers, when serum samples from 40 natural cases were tested in the acute and convalescent stages. In addition, common antigenicity was demonstrated between the virus of bovine origin and the Long strain of human RS virus by complement fixation test.

Animals

The value of the skin test and complement fixation test in the diagnosis of chronic pulmonary histoplasmosis.

Histoplasmin skin test results in patients with chronic pulmonary histoplasmosis from Missouri and Texas were compared to results in a previous study of U.S. Navy recruits. When consideration was given to geographic areas from which persons from each group were admitted to the study, it was found that the recruits were as likely to have a positive skin test as were those with the disease. In a similar manner, the Texas histoplasmosis patients were compared to groups of patients from that state with chronic obstructive pulmonary disease and with pulmonary tuberculosis. Again, no significant differences were found. It was concluded that the histoplasmin skin test is not of value in the diagnosis of chronic pulmonary histoplasmosis. Histoplasmosis complement fixation test data from the chronic pulmonary histoplasmosis group were compared to data from the chronic obstructive pulmonary disease and pulmonary tuberculosis groups. The usefulness of the complement fixation test in chronic pulmonary histoplasmosis is limited, as with any test, by false-positive and false-negative reactions. A decision theory method was used to define the limits of usefulness.

Chronic Disease

Evaluation of purified H and M antigens of histoplasmin as reagents in the complement fixation test.

Complement-fixation (CF) tests were performed with purified H and M antigens, histoplasmin, and Histoplasma capsulatum whole cell yeast phase antigen using sera of 126 patients with proven or suspected histoplasmosis. Specific titers for either H or for M antibody were obtained with the individual purified antigens; the highest titers were comparable to those obtained with histoplasmin. However, in sera containing only anti-M antibody, the titers obtained with the purified M antigen were 2 to 16 times those obtained with the histoplasmin or yeast phase antigens. The CF test for either H or M antibody was 4 to 32 times as reactive as the agar-gel microimmunodiffusion test; in general precipitin lines were obtained with either H or M antigens from sera with CF titers greater than or equal to 8. With sera containing H antibody, there was an excellent correlation between the CF titers obtained with purified M antigen and histoplasmin. The correlations of CF titers with H antigen and either histoplasmin or yeast phase antigen were very low.

Antibodies, Fungal

The complement fixation test and African trypanosomiasis. II. The complement fixation test as an aid for assessing therapy.

Complement-fixing antibody titres decline after successful treatment of trypanosoma infected cattle during a fixed period. For investigating the practicability of the resulting double test procedure in the field, cattle under controlled drug regimes were tested at treatment and again 3 weeks later. Alternatively, the results from groups of treated and untreated animals from the same area were compared. Both serological and parasitological test results indicated an insuffieicnt effectiveness of therapy in the area under investibation.

Animals

Studies on the immunogenicity of protamines in humans and experimental animals by means of a micro-complement fixation test.

A complement fixation study with human, monkey and rabbit sera, using purified sperm nuclear basic proteins as antigens, led to the following conclusions. (1) Protamines, the sperm-specific basic nuclear proteins, may be immunogenic in mammalians. (2) Antibodies detected in the indirect immunofluorescence test on human swollen sperm heads in sera from infertile and vasectomized men, are directed primarily against human protamines. (3) The results obtained suggested that differences in the immunization site and/or in the configuration of the immunizing protamine, may lead to the formation of antibodies directed against different antigenic determinants. Autoimmunity to protamines, following vasectomy or in infertile men, is accompanied by the formation of antibodies cross-reacting with common antigenic determinants present in protamines of other species. Induction of immunity to protamines by means of immunization with protamines-RNA complexes (in rabbits), or protamine-insulin complexes (in humans), leads to the formation of antibodies reacting more specifically with the immunizing protamine, showing only slight cross-reaction with other protamines. (4) The histone-like fraction present in mature human spermatozoa is composed mainly of histone fraction H2B.

Animals

[Evaluation of the agglutination test (AT), complement fixation test (CFT) and the antiglobulin test (AGT) in the diagnosis of swine brucellosis. III. Basic studies].

In the examinations of the swine sera obtained from swines immunized s.c. with adjuvant Br.abortus S19 vaccine or Br.suis 1417 vaccine, it was found that agglutinins were present after 3 weeks, and C.F. antibodies or incomplete agglutinins normally after injections. Probably, in the first period of Brucella infection negative results of C.F.T. or AGT or both will be obtained. In the swine sera from Brucella free herds, agglutinins reacting with the Brucellognost antigen were present. The performance of mercaptoethanol test or C.F.T. lead in most cases to suitable diagnosis. In our conditions we have not obtained results which permit to classify AGT as a supplement test in serodiagnosis of swine brucellosis.

Agglutination Tests

[The use of hemagglutination inhibition tests and complement fixation tests for evaluation of immunity states and diagnosis of recent rubella infections].

Comparative HAI and CF study of German measles antibodies in 575 sera collected from subjects of different age gave positive HAI reactions in 87% of the cases and positive CF reactions in 55% of the cases. The greater sensitivity of HAI and the longer presence of these antibodies justifies the use of this test for investigating the state of immunity in German measles. The combined use of the two tests for the diagnosis of the disease is very useful especially when the first serum sample is collected some time after the onset when the increase in serum antibody titers can only be demonstrated by CF, as HAI antibodies reach a high titer soon after the onset.

Antibodies, Viral

The use of methanol extract of Leptospira interrogans in complement fixation tests for leptospirosis.

Methanol extracts were obtained from L. interrogans serovars icterohaemorrhagiae and canicola and L. biflexa serovar patoc. Human sera from 167 normal individuals and 40 patients with different infectious diseases tested by complement fixation tests showed negative reactions. Sera from 100 patients with a suspicion of leptospirosis were tested by complement fixation tests and microscopic agglutination reactions. Agreement of 84% was found for those two reactions. Positive microscopic agglutination tests at a dilution 1:20-1:400 with negative complement fixation tests were observed in 5% of patients and negative microscopic agglutination with complement fixation tests in the range of 1:20-1:1280 were observed in 11% of the cases.

Agglutination Tests

Comparative sensitivity of a cultural test and the complement fixation test in the diagnosis of adenovirus ocular infection.

The sensitivity of human embryonic kidney (HEK) cell culture and the complement fixation test (cft) in the diagnosis of adenovirus ocular infection has been compared. The optimum time for collection of specimens to obtain the best results by each test has been examined. Sixty-one (53%) of 116 patients with moderate to severe follicular conjunctivitis, clinically indicative of adenovirus infection, had serological evidence of infection or had the virus isolated from ocular swabs. Virus was isolated from 53 patients (45%) and significant antibody rises were found in 33 (27%). When each test was carried out under optimum conditions, virus was isolated from 82% of cases and serological evidence of infection found in 72%. Serological responses as detected by the CFT appeared to be inferior in infections caused by adenovirus type 7 to those encountered in infections due to adenovirus types 3 and 8.

Adenoviridae Infections

African swine fever. II. Detection of the virus in swine tissues by means of the modified direct complement-fixation test.

The modified direct complement-fixation test, supplemented with unheated normal calf serum, was used to demonstrate antibodies in sera of swine immunized to African swine fever virus. These antibodies did not react in the ordinary direct non-supplemented complement-fixation test.African swine fever complement-fixing antigen in infected swine tissue is not denatured by extraction with fat solvents. Consequently, good antigens devoid of non-specific reactivity were obtained by extraction with a mixture of acetone and ether. The virus was detected in infected swine tissue harvested one day after beginning of pyrexia. The modified direct complement-fixation test demonstrated cross-reactions between the six strains of virus studied.

Acetone