ON ANTI-IMMUNE-BODIES 113 



is not the case. The combination of anti-immune-body with 

 immune-body in no way interferes with the combination of 

 the latter with the cell-receptor, and, as Bordet himself 

 showed, the anti-immune-body acts by preventing the union 

 of complement. As Ehrlich and Sachs state, however, the 

 objections brought forward by Bordet entirely lose their 

 force if it is maintained that the anti-immune-body unites 

 with the complementophile group of immune-body. They 

 hold that the immune-bodies of a given species have the same 

 complementophile apparatus, and that it is a matter of 

 indifference which immune-body is used to produce the anti- 

 immune-body. The latter will act on all the immune-bodies 

 with the same complementophile groups. It must be 

 granted that the facts recorded with regard to anti-immune- 

 bodies appear in this respect to support Ehrlich 's hypothesis ; 

 whilst Bordet offers no theoretical explanation of the facts 

 demonstrated. What is clearly established is that the anti- 

 immune-body unites with a combining-group of the immune- 

 body which is not the cytophile group, and that this union 

 prevents the union of complement with the complex immune- 

 body + receptor. From the point of view of the animal 

 injected with immune-bodies, the development of the anti- 

 immune-body may be regarded as a mechanism for prevent- 

 ing the associated action of the immune-bodies and its 

 complement (though the action of other complements is also 

 annulled). 



This may be due to the anti-immune-body occupying the 

 complementophile group of the immune-bodies ; but that is 

 not absolutely proved. When we consider the combining 

 relationships of the different substances certain difficulties 

 arise which have not yet received an explanation. As shown 

 in a former paper, rabbit's and guinea-pig's complements 

 combine with the same group in lysis by means of an immune- 

 body from the rabbit, each keeping out the other from 

 combination. The same holds with regard to an immune- 



MTTIB j 



