AMBOCEPTORS 323 



Specificity of Amboceptors. It has been stated elsewhere in this 

 volume that amboceptors are highly specific bodies. This specificity is 

 not, however, absolute, for just as group agglutinins are produced by 

 one bacterium for closely allied species, so in like manner experimental 

 investigation by Ehrlich and Morgenroth, von Dungern, and others has 

 shown that immunization of an animal with the erythrocytes of another 

 animal would produce one chief hemolysin for these cells and a second- 

 ary hemolysin for the cells of another animal. For example, on immuniz- 

 ing a rabbit with ox blood a hemolytic serum was obtained that was 

 hemolytic not only for goat blood, but also for ox blood. These second- 

 ary amboceptors are known as group or partial immune bodies. Their 

 production may readily be understood when it is remembered that the 

 body-cells are conceived as being provided with various side-arms for 

 many different blood-cells, bacteria, etc. Now, if the erythrocytes of 

 the goat possess receptors not only for the particular goat-blood side- 

 arms of the body-cells, but also for the ox-blood side-arms, both sets of 

 side-arms will be attacked and consequently two amboceptors are 

 formed one, the main one, for goat corpuscles, and a secondary one 

 for ox corpuscles. Ehrlich and Morgenroth, therefore, claim that the 

 immune body of a hemolytic serum is composed of the sum of the partial 

 immune bodies, which correspond to the individual receptors used to 

 confer the immunity. Since the cells of various animals of the same and 

 of different species vary in the number and variety of side-arms or re- 

 ceptors, which are not present in another, the different combining group 

 possessed by a blood-cell or a bacterium will not, therefore, find fitting 

 receptors in every animal, and thus there may be a different variety of 

 partial immune bodies in two animals. This would lead to the possi- 

 bility of the occurrence of antibodies for the same blood-cell or bacterium, 

 differing from one another in the partial immune bodies of which they 

 are composed, depending on the variety of the animals used in preparing 

 the serum. 



This view is directly opposed to that of Metchnikoff and Besredka, 

 who believe that a certain immune body is always the same, no matter 

 what species of animal was used in preparing the serum. As will be 

 pointed out further on, in addition to theoretic interest, the subject 

 possesses great practical importance, for, as is well known, most cura- 

 tive serums are best prepared with many different strains of a particu- 

 lar microorganism because of certain differences in their antigenic prop- 

 erties, and if, in addition, the value of a bacteriolytic serum depends 

 upon the sum-total of the immune bodies, it may be advisable to secure 



