BACTERIOPHAGE AS AN ANTIGEN 



413 



After fifteen minutes 100 leucocytes have ingested 109 bacilli. Op- 

 sonic index = 1.6. 



Considering the data presented in the above experiments, there 

 can be no question but what some factor present in a bacteriophage 

 suspension exerts a very definite effect upon opsonization with the 

 homologous, bacteriophage-susceptible, bacteria. 



But these principles, formed during the process of bacteriophagy, 

 possess still another property. For when used as antibody in the com- 

 plement fixation reaction it functions as an amboceptor. The experi- 

 ment cited below is taken from among many others which gave identical 

 results. 



Antigen: This is prepared according to the method of Maurice 

 Nicolle. One loopful of an agar culture of B. dysenteriae Shiga is 

 suspended in 4 cc. of saHne. This suspension, heated at 100°C. for 

 five minutes, then cooled, serves as antigen. 



Antibody: An alcohol precipitate of a Shiga-bacteriophage suspension 

 is taken into solution in a quantity of saline equal to the original volume 

 of the suspension. This serves as antibody. 



The co7n'pleme7it is fresh guinea pig serum, titrated. 



The hemolytic system is the usual anti-sheep system. (See table 54.) 



That there is something in the bacteriophage suspension which 

 modifies the complement fixation reaction is obvious. Certainly the 

 principles present in the solution used as antibody do not of themselves 

 fix complement, as is evident from the results obtained with tube 6, 

 where it is clear that hemolysis is stimulated. 



With the very fragmentary knowledge which we now have, it is 

 hardly possible to draw any conclusions from this experiment. 



