Problems in Immunology 145 



logical specificity even by sensitive quantitative techniques, 

 although some physical properties are markedly altered by 

 removal of the basic groups. But these are merely super- 

 ficial skirmishings and serve only to emphasize the magni- 

 tude of the main problem. 



Immunology of Carbohydrates 



We are, however, not so helpless in dealing with another 

 large chemical group, the carbohydrates. In discussing the 

 immunology of these substances, it was at first necessary to 

 restrict oneself to the bacterial polysaccharides, such as 

 those of pneumococcus. Owing to the vision of Oswald T. 

 Avery, however, it was soon found that various plant gums, 

 notably gum arable and its product of partial hydrolysis, 

 were capable of reacting with certain pneumococcal anti- 

 bodies, with the formation of precipitates. The recent dis- 

 covery that glycogen gives similar precipitates in a number 

 of antipneumococcus sera makes it evident that every 

 carbohydrate is potentially immunologically specific. The 

 immunological reactivity of glycogen is all the more re- 

 markable since this substance is a normal synthetic product 

 of all animals, and hence, according to classical immuno- 

 logical theory, should not take part in immune reactions. 



Because the chemistry of the carbohydrates is in a more 

 advanced state than that of the proteins, and because the 

 methods used for the determination of fine structure are 

 not excessively laborious, it has been possible to make 

 several instructive correlations between chemical constitu- 

 tion and immunological specificity among these sugar de- 

 rivatives. 



The first instance in which this could be done followed 

 the demonstration by Goebel and his co-workers that the 

 specific capsular polysaccharide of Type III pneumococcus 

 was a polycellobiuronic acid and that the cross reaction 

 with Type VIII was due to the presence in the Type VIII 



