272 IMMUNO-CATALYSIS 



Tagnon (1942), Tagnon, et al. (1942), Kaplan, et al (1942) 

 showed that chloroform-activated serum acting on fibrinogen, fibrin, 

 gelatin, and casein produces proteolytic digestion indicated by the pro- 

 gressive formation of non-protein nitrogen from these substrates. Chris- 

 tensen (1945) reported that lysis of fibrin clot taking place with the 

 participation of bacterial factor is likewise associated with proteolysis. 

 Garner and Tillett (1934b) had reported that if fibrinogen is incubated 

 with bacterial fibrinolytic factor for a brief period, it can no longer be 

 changed to fibrin upon the addition of thrombin. Nevertheless they 

 concluded that the degradation of the fibrinogen molecule is not great. 

 Jablonowitz (1938) reported that bacterial factor changes the speci- 

 ficity of the fibrinogen, as evidenced by the change in the quantity 

 of the precipitates when mixtures of bacterial factor and fibrinogen 

 are tested with antifibrinogen serum. In the light of recent studies it is 

 apparent that Garner and Tillett, and Jablonowitz were experimenting 

 with fibrinogen contaminated with serum-protease liberated during 

 the action of bacterial factor on fibrinogen. 



From the standpoint of understanding the role of bacterial fibrino- 

 lytic factor in the lysis of fibrin formed from serum, plasma or impure 

 fibrinogen several points should be emphasized. It is to be noted that 

 a plasma clot or fibrin is dissolved, in the absence of bacterial factor, 

 when serum or plasma are treated by organic solvents such as chloro- 

 form, ether, alcohol or acetone. Also treatment with concentrated solu- 

 tion of sodium chloride, adsorption with talc or kieselguhr, simple 

 dialysis, or merely standing can activate the inert fibrinolytic or proteo- 

 lytic enzyme in serum. 



The liberation of fibrinolysis from its inactive complex in serum was 

 reported by Ungar and Mist (1949) under the following conditions: 

 (a) by adding the specific antigen to serum from sensitized guinea 

 pigs, and (b) by mixing normal guinea pig serum with peptone, agar, 

 hyaluronic acid, chondroitin sulfuric acid, glycogen, pneumococcal 

 polysaccharide, and heparin. In other words, treatments with these non- 

 specific means produce the active enzyme from whatever state it may 

 have been present in normal serum. It is interesting to keep in mind 

 the fact that streptococcal fibrinolytic factor produces the same effect on 

 inert serum as, for example, a simple dialysis. It is difficult to conceive 

 that, under these conditions, the inert state of the serum enzyme mole- 

 cule per se undergoes a chemical structural change to yield an enzy- 



