SUBSTITUTION OF HUMAN BLOOD CELLS BY MONKEY'S 



RED CORPUSCLES IN PERFORMING THE COMPLEMENT 



FIXATION TEST FOR SYPHILIS ^ 



By Otto Schobl and Carlos Monserrat 



{From the Serum Section of the Biological Laboratory, Bureau of Science, 



Manila) 



The absence of natural haemolytic amboceptor in human serum 

 makes the use of antihuman amboceptor and human red cells 

 preferable to those methods which employ antisheep haemolytic 

 system. However, there is a practical difficulty connected with 

 this method, namely, the comparatively low titer of the anti- 

 human amboceptor as usually obtained by immunization of rab- 

 bits with human red corpuscles. A considerable number of in- 

 jections is necessary, and strictly fresh blood not always being 

 available to a laboratory worker who happens to be without 

 direct connection with a hospital or a similar institution, a high 

 percentage of rabbits die before they yield serum strong enough 

 to be useful for a test. 



It occurred to us that, on account of the biologic relationship, 

 monkey's red cells may probably behave in a similar way as 

 human corpuscles in this respect. These animals, common in tro- 

 pical countries, are inexpensive and easily maintained about the 

 laboratory. Thus a supply of fresh blood is always at hand, 

 since repeated bleedings taken directly from the animal's heart 

 are tolerated without any apparent harm to the animals. 



In order to establish the usefulness of monkey's red cells in 

 performing the complement-fixation test for syphilis, the follow- 

 ing question had to be answered: 



1. It had to be determined whether or not human serum con- 

 tains natural haemolytic amboceptor toward monkey's red cor- 

 puscles. 



2. The practicability of producing high value antimonkey 

 haemolytic amboceptor had to be established. 



3. A series of comparative tests with sera submitted fof 

 routine examination had to be carried out to determine if there 

 is any lessening in the accuracy of the test when monkey's red 

 corpuscles are used as compared with the method in which human, 

 red cells are employed. 



' Received for publication June, 1917. 



249 



