Conventional Complement Fixation Test Research Articles

Utility of complement fixation and microimmunofluorescence assays for detecting serologic responses in patients with clinically diagnosed psittacosis.

The serodiagnosis of human psittacosis was considerably improved by a microimmunofluorescence (MIF) assay that uses selected strains of Chlamydia psittaci, C. pneumoniae, and C. trachomatis as antigens. The 78 patients examined in the study were clinically diagnosed as having psittacosis on the basis of compatible clinical symptoms following exposure to sick birds. The conventional complement fixation (CF) test identified 36 patients, or 46% (36 of 78) of the total, as positive. Antibody responses to C. psittaci were demonstrated by the MIF test in all 36 CF-positive patients. The MIF test also detected antibody responses to C. psittaci in 12 patients (15% of the total) whose sera were negative or anticomplementary in the CF test. Seven patients, or 9% (7 of 78) of the total, were identified by the MIF test as having C. pneumoniae infections. About 30% of the study patients (23 of 78) showed no serologic evidence of either C. psittaci or C. pneumoniae infection by both the CF and the MIF tests. Four distinctive serologic reaction patterns were observed in the study patients. Recognition of these reaction patterns and judicious corroboration of serologic responses to the chlamydial species by the MIF test with epidemiologic and clinical information will increase the efficiency and accuracy of serodiagnosis for human psittacosis.

Comparison of the Johne's absorbed EIA and the complement‐fixation test for the diagnosis of Johne's disease in cattle

A commercially available absorbed ELISA for the diagnosis of Johne's disease (JD) (paratuberculosis) in cattle, the Johne's Absorbed EIA, was compared with the conventional complement-fixation test (CFT) used in Australia. Stored plasma from 3 Victorian dairy herds with a history of JD, sera from specimens submitted from animals showing clinical signs of JD and sera from the US National Repository for Paratuberculosis Specimens were used to determine the sensitivity of each test. The EIA detected 48.8% of 43 Australian animals with subclinical JD, while the CFT detected only 12 (21.4%) of 56 subclinically affected cattle. Of 150 subclinically infected US cattle, the EIA detected 47.3% and the CFT detected 52.0%. The EIA detected 59.7% of animals which at the time of sampling were shedding Mycobacterium paratuberculosis in their faeces, but showed no clinical signs of JD, while the CFT detected 57.3%. The EIA correctly identified 88.2% of 136 histologically confirmed clinical cases, and the CFT detected 83.4%. The specificity of each test was determined by testing sera collected at slaughter from animals residing in a known JD-free area of Australia, and from samples from the US National Repository of Paratuberculosis Specimens collected from certified-free herds in Wisconsin. The EIA was found to have a specificity of 99.8% when 998 Australian animals were used as the test population, and 99.0% when 196 US animals were used. The specificity of the CFT using Australian samples was 96.9% and 95.2% using American samples.

Application of the single radial complement fixation test for serodiagnosis of influenza, respiratory syncytial, mumps, adeno type 3, and herpes simplex type 1 virus infections.

A stabilized modification of the single radial complement fixation (SRCF) test in gel was developed for detecting various virus antibodies. The principle of the test is based on the use of a single-stage procedure with an agarose plate containing virus antigens and antibody-coated erythrocytes, and thin plastic film coated with complement. By filling the wells in the agar plate with a 1:4 diluted heat-inactivated sera and covering the agar surface with a complement film, a zone of unlysed cells surrounded by a hemolytic area appears after incubation overnight at 4 degrees C and then for 1-2 h at 37 degrees C, depending on the antibody titers. The SRCF antibody titer is calculated numerically from the square of the diameter of the unlysed cell zone. The stability of reagents could be significantly improved using thin complement film and several stabilizers. When this test was used for serodiagnosis of influenza, respiratory syncytial (RS), mumps, adeno virus type 3 and herpes simplex type 1 virus infections (using a total of 400 sera), excellent correlations were demonstrated for antibody titers between conventional complement fixation (CF) and SRCF titers. Furthermore, the expression of antibody titer as an SRCF unit with consecutive value, produced results sensitive to fluctuations in the antibody titers. The simplicity of the procedure, stability of the reagents, and excellent correlation with the conventional CF test might make this a useful test for routine serodiagnosis and seroepidemiological survey of various virus infections.

Rapid rate-kinetic turbidometric assay for quantitation of viral complement-fixing antibodies

A rapid rate-kinetic turbidometric assay for the quantitation of viral complement fixing antibodies has been developed, using adenovirus as a model. The procedure is based on the turbidometric quantitation of intact sheep erythrocytes and measures the rate of hemolysis (change in absorbance at 640 nm/min), at maximum velocity, occurring in the presence of residual complement not fixed by the antigen-antibody reaction. Reagents were standardized and assays performed using a microprocessor-controlled spectrophotometer with kinetic assay capability and a thermoregulated cell compartment. Eleven sera were assayed for complement fixing antibodies both by the conventional microtiter technique and by the rapid turbidometric method described here. Good correlation ( r = 0.89) was obtained between the two procedures. Unlike the conventional complement fixation test, the rate-kinetic turbidometric complement fixation assay was found to be tolerant of variation in complement and antigen concentration, endpoint titers were objectively quantitated and, once reagents had been standardized, results could be obtained within 45–60 min. The technique is potentially adaptable to large-scale automation.

Single radial complement fixation test for assaying antibody to influenza virus type-specific antigens.

An immunodiffusion technique in agarose is described for assay of complement-fixing antibodies against the type-specific soluble antigen of influenza virus. Under the test conditions, positive human serum produced a definite unlysed zone around the well, and the annulus area showed a high correlation with the antibody level in a conventional complement fixation test with log2 serum titer. This paper also describes the use of this method as a diagnostic procedure for the assay of antibodies against soluble antigens of influenza A and B viruses in paired human sera collected from persons infected with the virus or who received ether-split vaccine. This method appears to more sensitive and gives more consistent results for serodiagnosis of infection cases than do the hemagglutination inhibition, neuraminidase inhibition, and complement fixation tests. Our results suggest that the single radial complement fixation test can provide a simple and reliable method for serodiagnosis of influenza virus infection.

Enzyme-linked immunosorbent assay for mumps and parainfluenza type 1 immunoglobulin G and immunoglobulin M antibodies.

A solid-phase enzyme-linked immunosorbent assay (ELISA) for detection of mumps and parainfluenza type 1 antibodies (immunoglobulin G [IgG] and IgM classes) is described and compared with the conventional complement fixation (CF) test. A highly positive correlation was found between mumps IgG ELISA and the mumps CF test, whereas parainfluenza type 1 IgG ELISA had only a moderate positive correlation with the respective CF test. Mumps IgM antibodies could be demonstrated in all patients with serologically verified and clinically typical (parotitis, meningitis, or orchitis) mumps virus infection, but not in patients with rises in parainfluenza CF titers. Mumps IgM was already present in the acute-phase sera if they were not taken during the first 2 days after onset of disease. Mumps IgM was also found in some paired sera that were taken too late to demonstrate any significant increase in the antibody titers by CF. Therefore, mumps IgM ELISA provides an improvement over the conventional laboratory diagnosis of mumps infection, since the measurement of specific IgM antibodies in a single serum by ELISA is diagnostic, rather than the identification of a fourfold or greater rise in CF antibody titer. An unexpected finding was that parainfluenza type 1 IgM antibodies could not be demonstrated by ELISA in paired sera with rises in parainfluenza CF titers, suggesting a different antibody response from that occurring in mumps infection.

Immune adherence hemagglutination test applied to the study of herpes simplex and varicella-zoster virus infections

The immune adherence hemagglutination (IAHA) test has been used successfully to detect antibody to herpes simplex (HS) virus and varicella-zoster (V-Z) virus. Comparative studies between the complement-fixation (CF) test and the IAHA test revealed that, in most cases, the IAHA test was more sensitive than the CF test. Furthermore, diagnosis on the basis of a fourfold change in antibody titer was made more rapidly by the IAHA test. The IAHA test was found to be a very simple and practical technique requiring only a few hours for completion compared with the conventional CF test which required up to 24 h. In addition, both sera and cerebrospinal fluids could be tested in very low dilutions in the IAHA test, so that very low levels of antibody could be detected. Also, the IAHA test detected antibody to V-Z virus more frequently than did the CF test in adults with a history of varicella occurring 9 to 30 years prior to sampling. The level of cross-reaction between HS and V-Z viruses was examined by both the CF test and the IAHA test, and no major differences between the two techniques were found.

Immunologic Studies with Fractions of Virulent Treponema Pallidum

Summary The preparation of a serologically reactive substance from virulent T. pallidum by use of desoxycholate extracting solution is described. Preliminary findings bearing on the physical properties and chemical characteristics of the desoxycholate extract are presented. The desoxycholate extract has been employed in a conventional complement fixation test. Antigen lots have shown excellent reproducibility as measured by serologic behavior and the measurement of TPCF antibody has likewise been found to be highly reproducible. The separate identity of TPCF antibody from TPI antibody and reagin is suggested by absorption, inhibition, and correlation studies. A possible relationship to non-reagin agglutinating antibody is suggested. Data bearing on the specificity and sensitivity of the TPCF are presented and discussed.