730 



ANTIGENIC PROPERTIES OF THE BACTERIAL CELL 



with the effects of which we are familiar as agglutination, precipitation, opsonization, 

 etc., effects which we believe to be due to a single sensitizing anti-substance.' The 

 response to the "complete" bacterial antigen is highly specific, as in the case of the 

 pneumococci, where it is strictly type specific. In vitro these antibodies not only react 

 with the bacteria themselves, but with the carbohydrate soluble specific substances 

 provided from them. 



When the bacterial cell is dissolved, either by bile, as in the case of the pneumo- 

 cocci, or, again, by chemical means such as extraction with alkali, and precipitation 

 with acetic acid in the cold, this "complete" antigen is broken up into the nucleopro- 

 tein and the soluble specific "residue." 



TABLE I 



* It must be remembered that the so-called "concentrated" solution represents the original solution, probably contain- 

 ing relatively little of the dry material. 



The nucleoprotein injected into animals will produce antibodies, but these anti- 

 bodies react slightly with the whole bacteria and not at all with the soluble specific 

 substance. Their specificity, moreover, is less strictly limited than that of the anti- 

 bodies produced with the whole antigen. 



The "residue" or soluble specific substance is not in itself antibody producing. It 

 represents what Ehrlich would have called the "haptophore group" of the bacterial 

 antigen, in that it reacts, with precise specificity, with the antibodies produced by the 

 "complete" antigen; but injected into the animal in large quantities and for long 

 periods, it induces no antibody formation whatever. 



These relations were established by slightly different methods but with identical 

 conclusions at about the same time by Avery and Heidelberger^ and by one of us with 

 Tamiya.^ Table I, taken from our own paper, illustrates the actual conditions as they 

 are observed experimentally. 



■Zinsser, H.: /. Immunol., 6, 289. 1921. 



^ Avery, O. T., and Heidelbcrger, M.: J. Exper. Med., 42, 367. 1925. 



^ Zinsser, H., and Tamiya, T. : loc. cit. 



