Complement-mediated lysis of sheep erythrocytes coated with optimal concentrations of rabbit IgG hemolysin was inhibited by euglobulin fractions from the sera of patients with seropositive rheumatoid arthritis. That this was due to direct interaction with the IgG coat on the red cell rather than a nonspecific reaction with complement in the fluid phase was confirmed by controls using cells coat...

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 p...

Culture filtrates and autolysates of Coccidioides immitis have provided suitable crude antigens for the serodiagnosis and prognosis of coccidioidomycosis. One of these, a heat-labile antigen which participates in the immunodiffusion reaction corresponding to the complement fixation reaction (IDCF), has been characterized as a 110-kDa native protein that, when subjected to reducing conditions an...

A simple gel-diffusion technique is described for the diagnosis of ram epididymitis caused by Brucella ovis. The results are shown to be very similar to those obtained by the complement-fixation test, which is currently the standard method of diagnosis. The method is suitable for use in the field and is expected to facilitate the control of ram epididymitis in areas where laboratory facilities ...

The applicability to the non-hemolytic streptococci of the technique used for the extraction of a soluble precipitating substance from the hemolytic streptococci is demonstrated. With this substance as antigen, it is demonstrated by means of precipitation and complement fixation that the non-hemolytic streptococci form an antigenically distinct, but entirely heterogeneous group. Such cross-reac...

Sera from 452 patients and blood donors were tested for antibodies to Tryp-anosoma cruzi. The complement fixation test and a counterelectrophoresis test were used. The results showed that both tests agreed in 92% of the sera. However, the counterelectrophoresis test was not as sensitive as the complement fixation test.

Previous studies from this laboratory have demonstrated that Mycobacterium leprae, an obligate intracellular bacterial parasite, enters human mononuclear phagocytes via complement receptors on these host cells and bacterium-bound C3. The present study investigates the role of M. leprae surface molecules in C3 fixation and phagocytosis. By enzyme-linked immunosorbent assay, C3 binds selectively ...

A haemolytic assay was used to test the complement fixation ability of 16 serum samples with high concentrations of anti-cardiolipin antibodies. Fourteen patients had clinical complications usually associated with these antibodies--namely, recurrent abortions, thrombosis, or thrombocytopenia. Complement fixation by anticardiolipin antibodies was shown in only four of these patients and was not ...

Complement fixation titers of 1:2 and 1:4 with coccidioidin are not always of diagnostic significance. The concurrent use of the complement fixation and immunodiffusion tests is an effective means for specific serologic diagnosis of coccidioidomycosis in patients with low levels of complement-fixing antibodies. In routine testing, it is recommended that only sera that are negative for complemen...