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The ELISA technique has been found to be reliable for the detection and titration of cytomegalovirus-specific IgG antibody in serum. It is about six times more sensitive than the CF test although some discrepancies were found between the antibody titres determined by the two methods.
A total of 409 serum and cerebrospinal fluid specimens from human subjects with proven coccidioidomycosis, with other infections, or with no apparent illness were tested for antibodies to Coccidioides immitis by the Premier EIA (Meridian Diagnostics, Inc., Cincinnati, Ohio), which tests for immunoglobulin G (IgG) and IgM responses to coccidioidal antigens, and by the conventional complement fixation (CF) or immunodiffusion (ID) assays for antibodies corresponding to those detected by the tube precipitin (TP) or CF tests. Of the 409 specimens, 47 were from persons with confirmed coccidioidomycosis and all were positive for C. immitis antibodies in IDCF tests and enzyme immunoassays (EIAs) for both IgG and IgM. The EIA for detecting both IgG and IgM antibodies proved to be sensitive for detecting coccidioidomycosis case sera positive by the IDCF, IDTP, and CF tests. Maximal sensitivity for diagnosing coccidioidomycosis is dependent upon detection of both IgG and IgM antibodies in the EIA. The EIA, however, was not absolutely specific, since some sera from patients with confirmed blastomycosis and some from patients with noncoccidioidal disease produced false-positive reactions.
A comparison between a BCG antigen and various batches of an antigen extracted at different times from leishmania cultures in the fixation of complement reaction is reported. A better response was obtained with BCG (further confirmation on a larger series is being sought), whereas the leishmania antigens were difficult to prepare and their batch titres were not constant.
In this study, improvements were made in the technique and the preparation of the antigen. It was possible to perform three extractions and elutions resulting in a soluble reactive preparation from each batch of infected mouse brain. This led to an appreciable increase in the yield of highly reactive antigen. The presence of bluetongue antibodies was not detected in 13,210 sheep sera. Of the 13,486 bovine sera tested, only three questionable reactions were obtained. It was possible to determine that two of these animals were imported. Various isolation methods, including transmission trials to susceptible sheep followed by serological tests on the sheep sera, failed to confirm the infection in the three reactors.
Antigens derived from three different yeast strains of Histoplasma capsulatum (GW and VC used by the Veterans Administration Serology Reference Laboratory and the Centers for Disease Control reference antigen, A811) were compared with each other to determine their equivalency. Results from 200 sera, tested concurrently by the Serology Reference Laboratory and the University of Kentucky Mycoserology Laboratory, indicated that the VC yeast antigen gave better correlation to the A811 antigen than did the GW antigen.
The use of a gel filtration method allowed us to obtain pure IgM fractions to be tested for specific Toxoplasma serology. The good correlation found in our series between IgM-IFAT and LBCF-H100-TTE performed on pure IgM fractions suggests that LBCF-H100-TTE may be another useful serological test for detection of IgM antibodies although false negative results might occur when LBCF-H100-TTE is performed on IgM fractions of cord sera.
Highly type-specific soluble antigens (SA) of viruses of the tick-borne encephalitis (TBE) complex were obtained by treatment of the sucrose-acetone antigens with 8 mol/l urea. Each SA reacted with the homologous serum only. The serum to SA of strain Sofyin and of Omsk haemorrhagic fever virus distinguished the TBE complex representatives; the difference between homologous serum titres was in the range of 4-5 two-fold dilution steps.
A simple method for the preparation of a potent group-specific antigen on HeLa-229 cells infected with MRC-1 (LB) (TRIC/GB/MRC-1 Gf) strain of Chlamydia trachomatis is outlined. HeLa-229 cells are infected (MRC-1 strain, 102 inclusion-forming units per cell) with centrifugation at 4,000 g for 1 h in flat-bottomed vials. The cells are removed by brief trypsinization with 0.25% trypsin and put into 75 cm2 culture flasks (12 x 106 cells by flask) in BHK-21 medium supplemented with foetal bovine serum. The flasks are incubated for 5 days at 37 degrees C. The destroyed cell monolayer and the supernatant are centrifuged at 100,000 g for 1 h. The pellet is collected and resuspended in PBS and subjected to ultrasonic vibration for 30 min. This antigen may be used for detection of complement-fixing antibodies in lymphogranuloma venereum and ornithosis.
Sera of cows with brucellosis and those originating from heifers vaccinated with S19 strain, were investigated. A great negative relationship was observed between the frequency of CFT prozone occurrence and the living conditions of the animals; the individual properties of the animals were less significant, and the experimental error still lesser. No relationship was found between the kind of animal stimulation (field infection or S19 vaccination), the stadium and severity of the disease, the CFT titre level, and the animal age. The herd prozone frequency showed a normal distribution in the coordinate system.
The purpose of this paper was to developed simple and accurate methods for standardization of the particular components of a hemolytic system and to choose optimal amounts of these components in CFT. On the basis of comparative studies and the data from literature the following procedure was chosen: 1. Sheep's blood was conserved with Alsever liquid and used after 5 days of stabilization. A 2% suspension of erythrocytes was standardized by centrifuging in calibrated test tubes at 1000 r for 10 min and spectrophotometrically, assuming the following criterion: the suspension of erythrocytes dissolved in distilled water at 1:10 ratio should show 0.500 extinction (E541), which corresponds to 5 X 10(8) erythrocytes in 1 cm3. 2. Lyophilized hemolysin was dissolved, conserved with glycerol and used after 5 days of stabilization. Hemolysin was titrated with 100% hemolysis in the presence of the excess of complement. The suspension of erythrocytes was sensitized with 5 units of hemolysin directly before using it. 3. Lyophilized complement (C) was dissolved, conserved with boric acid +K2SO4 containing liquid and used after 5 days of stabilization. Titration of C was done by 50% hemolysis; 3C'H50 was used in CFT. 4. A barbital buffer was used as diluent at pH 7.3-7.4, alternatively 0.85% NaCl with an addition of Ca and Mg at optimal concentration. The hemolytic system was incubated at 37 degrees C for 30 min.
Clinical and serological follow-up of 7 patients submitted to renal transplantation and presenting positive serological reactions to Chagas' disease before immunosuppression did not show significant changes in indirect immunofluorescence and complement fixation titres for Chagas' disease, or signs and symptoms indicating exacerbation of the disease during follow-up. In addition, 18 of 66 recipients of renal transplants considered to be non-chagasic before immunosuppression showed at least one positive result to the indirect immunofluorescence test for Chagas' disease during the study period. The results suggest that the immunosuppression state induced in chagasic patients submitted to renal transplant did not promoted exacerbation of the chronic infection in these patients and not interfere with the serological response of chronic chagasics, thus permitting the use of these serologic reactions for diagnostic purposes in these cases. However, the positive results of the indirect immunofluorescence test in non-chagasic patients indicate the need for judicious interpretation of the indirect immunofluorescence test for the diagnosis of Chagas' disease in renal transplanted patients.
The activity of cellular antigens and those as aqueous extracts prepared from 4 laboratory strains of Brucella abortus: 99, S-19, 119-3 and "Krotz" has been compared in this paper. The purpose of the studies was to select an antigen of the highest activity and to test it by the Polish Standard of anti-Brucella abortus serum. It was shown that cellular antigens are more active in CFT than aqueous extract antigens of the same brucella strain. Cellular suspension of Br. abortus strain S-19 was chosen for production of the domestic antigen. A chessboard system was used in standardization of this antigen. In the working dilution of the antigen in CF such an amount of it was used that gave the titre 250++ according to the Polish standard of anti-Brucella abortus serum. The multiplier 4 (1000:250) was obtained which serves to calculate CFT titres in terms of international units of the complement fixing antibodies (icftu) in 1 cm3 of the serum studied. In examinations of all species of farm animals by the standard CFT technique, 10-20 icftu were assumed as a doubtful result and greater than or equal to 20 icftu as a positive result. A definite excess of the antigen used in working solution limits the prozone range and permits to carry out CFT in mass diagnostic examinations initially using one lowest serum dilution.
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