340 STUDIES IN IMMUNITY. 



II. THE NATURE OF A SO-CALLED "COMPLEMENTOID." 



In his analogy between antitoxic and hemolytic sera Ehrlich 

 presupposed the existence of substances called " complementoids " 

 derived from " complements/' as "toxoids" are supposed to be 

 derived from toxins. These "complementoids" are depicted as 

 possessing a "haptophore group" but no "zy mo toxic" group, in 

 distinction from complements, which have both. That is, they 

 have none of the toxic or hemolytic activity of complements, but 

 may give rise, when injected, to " anticomplements," and may, under 

 certain conditions, combine with amboceptors. After the hypothe- 

 sis followed apparent experimental proof of the existence of such 

 bodies. Ehrlich and Sachs* described a phenomenon which occurs 

 in dog serum which they call "Verstopfung der Ambozeptoren 

 durch Komplementoide, " -the plugging of amboceptors by 

 means of complementoids. The details are briefly as follows: Fresh 

 dog serum hemolyzes guinea-pig corpuscles. Dog serum heated 

 to 51 C for one-half hour loses its power to produce this hemolysis 

 owing to the destruction at this temperature of the very labile 

 complement. This heated serum (Ambozeptor) may be reactivated 

 by guinea-pig ''complement." If, however, the corpuscles are left 

 in contact with the heated dog serum at 37 C for 2 hours the 

 subsequent addition of fresh guinea-pig serum produces no hemoly- 

 sis. f This fact is ascribed to a plugging of the " complementophilic 

 arm" of the dog amboceptor by means of the " complementoids " 

 present in the serum heated to 51 degrees. The amboceptor is said 

 to be destroyed by a temperature of 60 degrees; the somewhat 

 unusual nature of this amboceptor is fully discussed in another 

 place by Sachs,:): but need not concern us here. 



* Ehrlich and Sachs, See Collected Studies on Immunity, Ehrlich-Bolduan, 

 John Wiley & Sons, p. 209. 



f Although experimental proof that the subsequently added alexin has not 

 been combined is not offered by the authors, such a matter is easy to determine. 

 If we centrif ugalize such a tube and to the supernatant fluid add heated dog serum, 

 and then corpuscles; hemolysis is produced, showing that the alexin has really 

 been kept out of combination by the heated dog serum united to the corpuscles. 

 The control is a tube in which hemolysis has occurred by the addition of dog serum 

 and alexin at the same time, in which case no subsequent alexic activity is 

 detectable. 



t Sachs, H., See Collected Studies on Immunity, Ehrlich-Bolduan, John 

 Wiley & Sons, idem, p. 186. 



