A Study of the Thermolabil and Thermostabil Antilysins (Anticomplementary Substances) of Human Serum
Authors: Kyutoku Takaatsu 
Published: January 2023

Summary and Conclusions
Anticomplementary substances (antilysins) in human sera may be divided into two kinds: (a) those removed by heating at 56°C. (thermolabil antilysin) and (b) those not removed by heating (thermostabil antilysin). Human sera do not develop antilysins as a result of heating, as may occur with rabbit, dog and mule sera. Steril sera develop thermolabil but not thermostabil antilysins. Steril sera kept at 37°C. may develop these thermolabil antilysins in from three to seven days; at room and lower temperatures (0 to 2°C.), longer periods are required. Fresh sera rapidly dried in filter paper do not develop anticomplementary properties. Human sera containing various bacteria and particularly staphylococci rapidly develop thermolabil and thermostabil antilysins. Staphylococci alone rather than their products elaborated during cultivation in broth and serum, produce the antilytic effects of contaminated serum. Large amounts of hemoglobin in salt solution and serum, steril and contaminated, exert anticomplementary activities before and after heating. Traces of hemoglobin are usually free of these antilytic effects. Steril and contaminated sera containing antilysins gradually become alkaline in reaction; neutralization of this alkali with hydrochloric acid does not remove the antilytic activities of the sera. Definite changes in the hydrogen ion concentration of steril and contaminated human serum before and after the development of antilysins, could not be determined with colorimetric methods. Steril human sera containing thermolabil antilysin showed a slight increase of total protein and especially of the globulin fraction, as determined by the refractometric method of Robertson; contaminated sera containing thermolabil and thermostabil antilysins showed a marked increase of total protein and especially of the albumin fraction, probably due in part to the presence of bacteria. Anticomplementary sera passed through a Kitasato filter which removes the antilysins, showed a reduction in total protein and especially of the globulin fraction. Heating anticomplementary sera at 56°C. for thirty minutes, which reduced the content of antilysins, had no appreciable influence upon the protein constituents. The removal of ether soluble lipoids from anticomplementary human sera did not remove the thermolabil and thermostabil antilysins. The antilysins of human sera are closely allied with the protein constituents and especially the globulin fraction. Absorption of human sera with barium sulphate tends to remove a portion of thermolabil and thermostabil antilysins; kaolin, bone ash and charcoal also remove antilysins, but to a lesser degree. Absorption of human sera with washed erythrocytes does not remove thermolabil or thermostabil antilysins as may occur with the thermostabil antilysins of dog serum; erythrocytes exposed to the antilysins of human serum do not acquire an increased resistance to serum hemolysis. Filtration of diluted human sera through new, chemically clean and steril Katasato filters removes all thermolabil and thermostabil antilysin; likewise the filtration of diluted heated dog serum removes the substances responsible for non-specific complement fixation reactions. Filtration of the sera of luetic persons has practically no influence upon the antibody concerned in the Wassermann reaction. Filtration of freshly prepared bacterial antigens removes the antilysins; filtrations of antigens for the Wassermann test as alcoholic extracts of beef heart reinforced with cholesterin diluted 1:20 with saline solution, does not remove the antilysin but completely removes the antigenic substance.
I beg to express my appreciation of the kindness of Professor Kolmer for outlining the experiments and technic of this investigation and for his supervision of the work; also to Dr. Charles Weiss, for aid in conducting the hydrogen ion determinations, and to Dr. Hatai and Dr. Toyama for aid in the refractometric work.