ANTI-ENZYME IMMUNITY 253 



that injections of chymotrypsinogen into female guinea pigs produced 

 no visible effect, but animals receiving trypsin and chymotrypsin 

 showed necrotic areas at the site of inoculation, and several of them 

 died. Chymotrypsin seemed to be more toxic than trypsin. Eagle and 

 Harris (1937) reported that trypsin injected intravenously into rabbits 

 caused almost immediate death. Large blood clots were found in the 

 heart and large veins. The free fluid was non-coagulable, and contained 

 no demonstrable fibrinogen. They stated that trypsin thus had initiated 

 blood coagulation in vivo as readily as it had done in vitro. 



In another experiment 10 ml. of a 5 per cent solution of crude tryp- 

 sin were injected intravenously into a rabbit weighing 2 kg. The ani- 

 mal died in convulsions in two minutes, and large clots were found 

 in the great veins two minutes after death. Likewise 1 ml. portions 

 of a 5 per cent solution of crude trypsin were injected into a rabbit at 

 10-minute intervals. One and one-half minutes after the fourth injec- 

 tion convulsions began and death followed in one minute. An autopsy 

 six minutes later revealed that the right ventricle and both auricles 

 were filled with solid clots. 



c. Neutralization of the Toxic EflFects of Trypsin with Immune 

 Serum. A mixture of 1 5 drops of immune blood and 4 ml. of trypsin 

 solution injected by Achalme into small guinea pigs was non-toxic. 

 There was no local effect, no vasomotor paralysis and no swelling of 

 the spleen. The injected mixture was immediately adsorbed. These 

 facts were believed by Achalme to have shown the complete neutrali- 

 zation of the toxicity of trypsin by its homologous antibody. A neu- 

 tralizing effect on the activity of papain by anti-trypsin immune sera 

 in in vitro and in vivo experiments was not observed. 



d. Antibody Against Papain. Several controversial works reviewed 

 by Walton and Segura (1932) have been published. A recent study 

 by Haas (1940) shows conclusively the formation of a specific anti- 

 body capable of inhibiting the proteolytic activity of papain prepara- 

 tions. The enzyme preparation with which Haas experimented was 

 obtained by subjecting papain puriss (Witte) to repeated fractional 

 acetone precipitation. It readily dissolved in water. For immunization 

 and serological, etc. experiments the solutions were filtered through 

 EK-Seitz filters. 



Guinea pigs immunized with a total of 2 to 3 mg. papain during a 

 period of 21 days experienced fatal anaphylactic shock with 0.2 to 



