STUDIES ON THE FLEX~ER GROUP OF DYSENTERY BACILLI II. THE CHEMICAL DEGRADATION OF THE SPECIFIC ANTIGEN OF TYPE Z SHIGELLA PARADYSENTERIAE (FLExNER)* BY FRANCIS BINKLEY, PH.D., WALTHER F. GOEBEL, P~.D., ANn

Boivin and his collaborators have investigated in some detail the decomposition of the specific antigens of Gram-negative microorganisms by hydrogen and hydroxyl ions (1). Under conditions of relatively mild acid treatment it was found that antigens derived from a variety of unrelated microorganisms were dissociated into their constituent components, a phospholipid and a serologically active polysaccharide. In addition, these investigators state that the antigens were rapidly destroyed by the action of dilute alkali. Our knowledge concerning the nature of antigens derived from Gram-negative bacilli was greatly advanced when Morgan and Partridge (2) found that, in addition to the phospholipid and polysaccharide components, a third constituent was liberated on acid hydrolysis. This substance proved to be a protein and was shown to be an important component not only of the specific antigen of the Shiga bacillus, but of the typhoid bacillus as well (3). In our studies on the antigens of the Flexner group of dysentery bacilli we too have found protein constituents analogous to those described by Morgan and Partridge (2, 3). I t has been observed that a protein-like moiety forms an integral part of t~e antigenic complex of each specific type of organism thus far investigated. In reviewing the work of other investigators it can be said in general that emphasis has been placed upon the chemical composition of the antigenic complexes, and but few data regarding the toxicity of the dissociation products have been given.