RELATION OF LEUKOCYTES TO IMMUNITY 307 



Opie found that two distinct proteolytic enzymes could be ex- 

 tracted from the cells of exudates obtained by turpentine injections. 

 One peculiar to the polynuclear leukocyte, and similar to one pre- 

 viously described by Miiller 42 acts in a weakly alkaline medium. 

 The other, present particularly in exudates containing a predominat- 

 ing number of mononuclear cells, acts in a weakly acid reaction. 

 Tschernorutski also found proteolytic ferments in both micro- and 

 macrophages, but found no lipase in the polynuclear extracts. This 

 seems particularly interesting in view of the great resistance to 

 intracellular digestion noticed in acid-fast bacteria, a point of some 

 importance in connection with the destruction in the body of such 

 micro-organisms as the bacilli of tuberculosis and leprosy. 43 Joch- 

 mann 44 states that the action of the leukoprotease, which acts in an 

 alkaline medium upon casein, results in the formation of tryptophan 

 and ammonia, and believes it to be functionally very similar to 

 trypsin. It is interesting to note that the most active protease is 

 obtained from pus as it forms about acute infections or other stimuli 

 which lead to the accumulation of polynuclear leukocytes, whereas 

 it is apparently completely absent from tuberculous pus. 



The question immediately arises, are these leukoproteases identi- 

 cal with the bactericidal substances extracted from leukocytes as de- 

 scribed above ? For it might well be that bacterial death resulted 

 merely from the digestive action of the enzyme upon the bacterial 

 protein. Jochmann, 45 who has approached this problem experi- 

 mentally, has answered it in the negative. By repeated alcohol 

 precipitation of glycerin extracts of leukocytes he obtained an en- 

 zyme preparation which possessed absolutely no bactericidal prop- 

 erties, though it was still actively proteolytic. 



Not only did this relatively pure ferment possess no bactericidal 

 action, but bacteria actively proliferated when suspended in it. Joch- 

 mann believes that living bacteria are not amenable to the enzyme 

 possibly because of their possession of an "antiferment," at least 

 this would follow in some cases from the experiments of Kantoro- 

 wicz. 46 



The leukoproteases, therefore, appear to possess no direct sig- 

 nificance in bacterial immunity. Their function seems rather to 

 lie in the resorption of dead tissues, fibrin, blood clots, etc. Friedrich 

 Miiller 47 has pointed out their possible importance in the rapid de- 

 struction and liquefaction of the massive fibrinous exudates remain- 

 ing after the crisis in lobar pneumonia. 



42 Miiller. Congr. f. inn. Med., Wiesbaden, 1902. 



43 Zinsser and Gary. Jour. A. M. A., 1911. 



44 Jochmann. Leucozyten Fermente, etc., "Kolle u. Wassermann Hand- 

 buch," 2d Ed., Vol. 49, 2. 



45 Jochmann. Zeitschr. f. Hyg., 61, 1908. 



46 Kantorowicz. Munch, med, Woch., No. 28, 1909. 



47 Friedrich Miiller. "Verhand. d. Kongr. f. inn. Med.," 1902. 



