Circulating antibody response in BCG vaccination, tuberculous infection and sarcoidosis

The bentonite flocculation test was used to differentiate antibodies formed by BCG vaccination from those produced by infections with virulent tubercle bacilli. Of 116 BCG-vaccinated nurses, only two (1.7%) showed antibody titres higher (1:128) than the threshold titre of 1:64 established for tuberculous patients.The bentonite test was also used to follow the course of infection in 54 patients with tuberculosis. A good correlation was found between the clinical course of the disease and O.T.-bentonite titres on repeated serological testing.Tuberculosis-like antibodies were demonstrated in sarcoidosis patients. These antibodies, however, are globulins (7S), in contrast to the macroglobulins (19S) found in tuberculous patients.

Inhibition of the anti-globulin reaction by human immunoglobulin G and its fragments

The specificities of antibodies involved in the agglutination of anti-D sensitized human red cells was studied using IgG and its fragments Fc and Fab as inhibitors. It was shown that commercial anti-globulin sera and specific sheep anti-IgG serum react with the antigenic groups common to IgG and Fc. Anti-Fab serum on the other hand agglutinated anti-D sensitized red cells by reacting with the antigenic groups common to IgG and Fab. This result is interpreted to mean that antibodies reacting with Fab have different specificities depending on whether IgG or Fab was used as antigen.