i6 



Scientific Proceedings (35). 



1 1 (421) 



The fate of so-called syphilitic antibody in the precipitin 



reaction. 



By HIDEYO NOGUCHI. 



[From the Laboratories of the Rockefeller Institute for Medical 



Research.] 



The Wassermann reaction for syphilis is also present in the 

 majority of cases of leprosy and it is impossible to distinguish 

 syphilitic and leprous sera by this test alone. With a view of 

 obtaining specific antisera capable of neutralizing the active prin- 

 ciples of syphilitic and leprous sera electively, rabbits were im- 

 munized with syphilitic and leprous sera, each giving positive 

 Wassermann phenomenon. Two more rabbits were injected with 

 normal and negative sera for controls. After several injections 

 given intravenously, these rabbits yielded the antisera, all ener- 

 getically precipitating for human serum. Before testing whether 

 the antiserum prepared by injecting syphilitic serum exerts a 

 specific neutralizing effect on the fixing property of that serum 

 only, it was necessary first to determine the complement-fixing 

 capacity of the precipitate formed by a normal serum and its anti- 

 serum. It was found that the entire bulk of precipitate formed by 

 mixing o. 1 cubic centimeter of normal serum and 0.02 cubic centi- 

 meter of its antiserum can fix 0.05 cubic centimeter of guinea-pig's 

 complement (using my antihuman hemolytic system), but is unable 

 to prevent hemolysis when 0.07 cubic centimeter of complement 

 is used. The precipitates formed by mixing syphilitic or leprous 

 serum with their corresponding antisera or the antiserum for 

 normal serum were also able to fix guinea-pig's complement in 

 about the same degree as in the instance given above. I next 

 proceeded to investigate whether the anti-syphilitic serum inhibits 

 the occurrence of the Wassermann reaction when added to a 

 strongly positive syphilitic serum. I selected four different syphi- 

 litic sera, each capable of fixing o. 1 cubic centimeter of guinea- 

 pig's complement in doses of from 0.003 to 0.005 cubic centimeter 

 by using inactivated sera. To o. 1 cubic centimeter of each serum 

 was added 0.02 cubic centimeter of the anti-syphilitic serum and a 

 precipitate was formed. After one hour's incubation at 37 0 C, 



