360 IMMUNOLOGY 



optically isomeric polysaccharides, e.g., p-aminophenol-glucoside 

 and the corresponding galaetoside. They diazotized these, using 

 nitrous acid and hydrochloric acid in the cold as discussed in 

 Chapter XVIII. These diazonium derivatives were readily coupled 

 onto the proteins (horse serum globulin) in the presence of 

 N/100 hydroxide. They then- studied and compared their antigenic 

 properties. The structural formulae for the two isomeric glu- 

 cosides used as haptens in these experiments are given by Avery 

 and Goebel (1929) as follows: 



NH, C >— O— C— H NH,<^ \— O— C— H 



■ ^ -^ i\ 



H— C— OH 



i \ 

 HO— C— H \ 



I 

 HO— C— H \ 



\ / 



I / 

 I / 

 \/ 

 H— G 



I I 



H,i=C— OH H„=C— OH 



p-aminophenol /3 glucoside p-aminophenol /3 galaetoside 



The specificity of the conjugated hapten proteins was checked 

 further hj linking the same diazotized glucosides not only to horse 

 serum globulins but also to egg albumen, Avery and Goebel* 

 summarize their results as follows : 



1. When two chemically different carl)ohydrate derivatives are 

 bound to the same protein, the newly formed antigens exhibit dis- 

 tinct immunological specificity. 



2. When the same carbohydrate radical is conjugated with two 

 chemically different and serologically distinct proteins both of the 

 sugar-proteins thus formed acquire a common serological speci- 

 ficity. 



3. The newly acquired specificity of the artificially prepared 

 sugar-proteins is determined by the chemical constitution of the 

 carbohydrate radical attached to the protein molecules. Simple 

 differences in the molecular configuration of the two isomers, glu- 



*Avery and Goebel: J. Exper. Med. 50: 533, 1929. 



