76 A. A. KANDUTSCH AND JACK H. STIMPFLING 



It is apparent that most of the antigenic activity present in the 

 whole Triton extract was concentrated in the TSL fraction. The 

 fraction of the whole Triton extract that was soluble in water 



Table I 

 Antigenic activities of the whole triton extract 



AND OF ITS SUBFRACTIONS 



Fraction 



Whole Triton extract 



TSL 



Water-soluble fraction 



None 



Whole Triton extract 



TSL 



Water-soluble 

 fraction 



None 



* The amount obtained from 7-5 or 0-75 mg. of whole Triton extract 



In the enhancement test, the number of mice dying as a result of the growth of the 

 tumour homograft is proportional to the amount of antigen injected. Preparations were 

 injected intraperitoncally in three equal doses at 4-day intervals into mice of strain B10.D2 

 (an H-2d subline of C57BL/10). Sarcoma I was inoculated subcutaneously 10 days after 

 the last injection. The derivation of the fractions tested is described in Fig. i. Antibody 

 titres were determined on individual sera obtained from 5 mice, 7 days after the last 

 injection. 



possessed only low levels of activity. Antibody titres in treated 

 animals were positively correlated with enhancement of tumour 

 homografts in the same animals. Similar results were obtained in 

 a number of other enhancement assays of fractions comparable 

 to those shown in Table I although the percentage of mice 



