On Non-specific Complement Fixation. 55 



34 (444) 



On non-specific complement fixation. 



By HIDEYO NOGUCHI. 



[From the Laboratories of the Rockefeller Institute for Medical 



Research^ 



Complement is fixable by various substances. It is fixed by 

 different extracts containing certain proteins. Fixation in this case 

 is direct and non-specific. On the other hand, complement is also 

 fixed by a combination of specific antigens and antibodies (Bordet- 

 Gengou). In the last instance, fixation is accomplished by the 

 cooperation of the antigen and antibodies, the latter being inert 

 without the aid of each other. From this observation the deduction 

 was formed that whenever complement is fixed by a mixture of two 

 substances, it is an expression of a specific reaction taking place 

 in such a mixture. This assumption, however, is permissible only 

 when the above phenomenon can be produced by none but the 

 specific antigens and antibodies. 



Recently I encountered a peculiar phenomenon which re- 

 sembles very closely the true Bordet-Gengou reactions, differing 

 from the latter in the non-specific nature of the substances serving 

 as antigen. Working on the sera of tuberculous patients, using 

 tuberculin and the nucleoprotein of tubercle bacilli as antigen, I 

 found that twenty out of twenty-five cases gave complement fix- 

 ation in varying degrees when tested in unheated state. Encour- 

 aged by this result, I examined thirty-five control cases without 

 tuberculosis and found, to my surprise, that twenty-eight of these 

 gave positive reactions with the same antigen. 



A subsequent study revealed that pepton, albumoses, glycogen, 

 various extracts of bacteria, tissues and organs, and certain cleav- 

 age products of protein 1 gave similar fixation phenomena. Thus 

 the phenomenon is found to be non-specific and is due to the ad- 

 dition of these substances to active human sera and it is present in 

 a majority of human sera. 



1 1 am greatly indebted to Dr. P. A. Levene who placed these substances at my 

 disposal. Among these may be mentioned allanin, glycil-glycin, leucin, tyrosin, 

 glycocoll ; these have, however, less fixing power than higher protein molecules and 

 glycogen. 



