WASSERMANN AND OTHER COMPLEMENT FIXATION TESTS 243 



ANTIGEN FOR THE WASSERMANN TEST 



Remembering that amboceptor does not fix complement unless the ambo- 

 ceptor's antigen is present, it is obvious that a syphilitic patient's serum, 

 containing syphilitic amboceptors, cannot fix complement unless syphilitic 

 antigen is present. Amboceptors are specific; they only act on the antigens 

 that stimulated their production. Antigens are specific; they will only facil- 

 itate complement fixation when they act with their own amboceptors. 



A priori, it would seem that the amboceptors of syphilis would be those 

 formed to destroy the treponema pallidum, that they would be specific for the 

 treponema pallidum and that the antigen for the Wassermann test would 

 necessarily consist of treponema pallidum. This is not the case. Such ambo- 

 ceptors are present, in varying amounts in the majority of syphilitic sera. They 

 usually constitute not more than 10 or 20 per cent, of the syphilitic amboceptors. 



The amboceptors almost constantly present in syphilitic sera, the major 

 amboceptor content of such sera, are specific for lipoid or lipoidal substance. 

 Consequently the ideal antigen for the Wassermann test is composed of trepo- 

 nema pallidum and lipoid or lipoidal extracts combined. The next best antigen, 

 and in most cases entirely sufficient, is a lipoidal extract without treponema. 

 The least valuable of all is a pure culture of treponema. 



Combined treponema and lipoid extracts are obtained by extracting the 

 liver or liver and heart of a syphilitic fetus with alcohol. Lipoid antigens are 

 alcoholic extracts or ether soluble-acetone insoluble extracts of the liver or liver 

 and heart of a normal fetus or a normal guinea-pig; they may also be made from 

 ox heart. 



When the method of preparation is identical, different extracts vary in anti- 

 genie value, whether they be made from syphilitic fetal tissue, normal fetal 

 tissue, guinea-pig tissue or ox heart. 



The antigenic value of any extract can only be determined by testing it 

 with a large number of known syphilitic sera and non-syphilitic sera, hence it is 

 necessary in the beginning to procure from a reliable source an antigen of estab- 

 lished value and standardized strength. The new antigens prepared by the 

 beginner are then tested by repeated comparison with the original and when 

 found to be equal to the original are stored for future use. 



All these extracts possess two properties: antigenic and anticomplementary. 

 The first is desirable, the second undesirable. 



In this connection, we may define antigenic as the power of causing fixation 

 of complement in the presence of syphilitic serum and in no other case; hence, 

 will show no hemolysis with a syphilitic serum at the end of a Wassermann test, 

 and show complete hemolysis at the end of a Wassermann test with all other 

 sera. 



Anticomplementary may be defined as the power of vitiating complement 

 under any and all circumstances, when used in sufficient amount; hence showing 

 no hemolysis at the end of a Wassermann test both with syphilitic and non- 

 syphilitic sera. 



When the smallest quantity of an extract that is anticomplementary is less 



