A Study of Antigens Active in the Middlebrook-Dubos Hemagglutination Test Present in Filtrates of Culture of Mycobacterium Tuberculosis

Abstract

A number of different fractions from heated and unheated culture filtrates of Mycobacterium tuberculosis have been studied in the Middle-brook-Dubos test, using rabbit antiserum. Cross inhibition tests provide no evidence for the presence in the various heated fractions of more than one important sensitizing substance. Cross inhibition tests with unheated fractions reveal the presence of at least two different sensitizing substances. One possesses the same specificity as that found in the heated preparations. The other is completely precipitable with saturated ammonium sulphate, while much of the heat-stable substance remains in the supernatant.