158 VETERINARY BACTERIOLOGY 



mime serum is termed amboceptor; 1 the thermolabile constituent 

 of normal serum is termed complement." 



Action of Amboceptor. It may be shown that the amboceptor 

 unites with the antigenic cell with which it comes in contact. 

 This may be demonstrated by the following experiment: A 

 heated immune serum (i. e. } one containing amboceptor only) 

 is added to the homologous cell, allowed to stand for a time, then, 

 by means of repeated centrifugation and washings with physiologi- 

 cal salt solution, the serum may be completely removed. To the 

 washed cells normal fresh serum (i. e., containing complement) 

 is added, when cytolysis may be observed. This seems to show 

 that the amboceptor unites with the cell and cannot be removed 

 by washing, but cannot, on the other hand, destroy the cell until 

 the complement is added. 



Action of Complement. Normal serum containing complement 

 only shows no cytolytic activity. An experiment reciprocal to 

 the preceding, the addition of complement containing serum to a 

 suspension of cells, followed by centrifugation and washing, and 

 the addition of amboceptor, will not result in cytolysis. The 

 complement is evidently not bound to the cell, and can only be 

 attached through the amboceptor. The amboceptor may be con- 

 sidered as a structure which links or binds the complement to 

 the cell and enables it to destroy such cell. 



Specificity of Amboceptors and Complements. The amboceptor 

 is formed usually as the result of immunization, and is specific 

 for its antigen. The amboceptor for the red blood-cells of one 

 species of animal will not unite with those of an unrelated species. 

 Inasmuch as normal serum will activate many different ambocep- 

 tors, it has been argued that all complement is of a single type, but 

 Ehrlich has succeeded in demonstrating that there are many 

 complements, and the general activating power of certain fresh 

 sera for many amboceptors is due to the multiplicity of the com- 

 plements which they contain. 



Structure of Amboceptor. There is reason for believing that the 



1 Synonyms of amboceptor are immune body, Imnmnknrpor, Zwischen- 

 korper, substance sensibilisatrice, copula, desmon, philocytase, fixateur, 

 preparator, Hilfkorper; 



2 Synonyms of complement are addiment, alexin, cytase. 



