434 IMMUNO-CATALYSIS 



toxins represent sera rendered toxic by partial removal of serum anti- 

 trypsin (lipids). 



Dead bacteria treated with serum became more resistant to the 

 proteolytic action of serum due to the adsorption of antitryptic lipids 

 from serum. Bacteria previously treated with serum or with oils do not 

 adsorb serum antitrypsin. 



Fresh guinea pig serum was mixed with typhoid bacilli, and placed 

 in the ice chest overnight (the serum so treated showed marked de- 

 crease in the antitryptic value). A portion of the mixture was cen- 

 trifuged until it became clear, and was then injected intravenously into 

 guinea pigs to determine its toxicity. Two ml. of clear supernatant 

 caused immediate death of a guinea pig weighing 210 grams, with 

 all the evidences of anaphylaxis. Repeated experiments yielded similar 

 results. This effect was claimed not to be due to the action of a toxin. 



Bronfenbrenner summarized (1944) the results of several of his 

 studies on the mechanism of anaphylaxis. He also believed that an 

 antigen-antibody reaction lowers the normal antitryptic titer of serum 

 yielding activated serum "trypsin." Tryptic action liberates heparin 

 preventing the clotting of the blood. Activated "trypsin" likewise 

 produces polypeptides and peptones. Combined action of activated 

 trypsin, and of polypeptides and peptones results in injury to tissue and 

 the liberation of histamine. As Jobling and Petersen (1914) reported, 

 Bronfenbrenner (1944, for earlier references) had found that serum 

 properly adsorbed with kaolin or starch in vitro also activates serum 

 ferments, with subsequent autodigestion of the serum, which produces 

 anaphylaxis-like symptoms when injected intravenously, especially 

 in homologous animals. 



The above observations are significant in relation to the shock pro- 

 duced by proteolytic enzymes. Since the blood histamine is in blood 

 cells and cell-free serum most likely is free from histamine, it does not 

 appear that the anaphylactic shock produced by sera treated in the 

 above manner could contain sufficient histamine to be responsible for 

 shock in the guinea pig. It may, therefore, be related to the action 

 of proteolytic factors. 



