XIX. CONCERNING THE MECHANISM OF THE ACTION 

 OF AMBOCEPTORS. 1 



By Prof. Dr. P. EHRLICH and Dr. H. SACHS. 



I. Blocking of the Amboceptor by Complementoids. 



THE complements which activate the amboceptors of blood serum 

 are, as is well known from the experiments of Ehrlich and Morgen- 

 roth, like the toxins characterized by two groups in the molecule, 

 viz., the haptophore group, which combines with the complemento- 

 phile group of the amboceptor, and the zymotoxic group, which 

 represents the actual carrier of the complement's specific function. 

 In complete harmony with this, Ehrlich and Morgenroth 2 could 

 show through the production of anticomplements by heating inac- 

 tivated sera, that the complements, like the toxins, under certain 

 circumstances are changed into inactive modifications. These mod- 

 ifications are still able to excite the production of antibodies, and 

 must therefore possess their haptophore group intact; in analogy 

 with the toxoids, therefore, they are called complementoids. Although 

 the presence of the complementoids could easily be shown by means 

 of animal experiments, it was impossible to demonstrate their react- 

 ing power by means of haemolytic test-tube experiments. The 

 reason for this was that a decrease of the complement action, such 

 as was to be expected in the inactivated sera (which really con- 

 stitute a mixture of amboceptor and complementoid), did not occur, 

 even when the complementoid was present in large amounts. Ehr- 

 lich and Morgenroth have therefore assumed that in the change from 

 complement to complementoid, the affinity of the complement's hap- 

 tophore group suffers a diminution. A similar assumption has been 

 made by Myers 3 for the toxoids of cobra poison. 



1 Reprint from the Berl. klin. Wochenschr. 1902, No. 21. 



2 See page 79. 



8 Myers, Cobra Poisons, etc., The Lancet, 1898. 



209 



