THE ESTIMATION OF CIRCULATING ANTIBODY-ANTIGEN COMPLEX

Abstract

Immune sera were subjected to treatment with alkali in the cold to cause dissociation of antigen-antibody complexes. Precipitates and a capacity to fix complement developed in some of these sera subsequent to such treatment. The specific immunologic nature of these phenomena and their observation in relation to disappearance of free antigen and appearance of free antibody in circulation are discussed. The phenomena observed appear to be consistent with the assumption that a circulating antibody-antigen complex is revealed as a result of treatment.