W. B. WHERRY 875 



INTRACELLULAR DIGESTION BY PHAGOCYTES 



Tschernoruzki' determined the presence of the following ferments in the leukocytes 

 of the dog — protease, amylase, dextrinase, catalase, nuclease, peroxydase — but the 

 absence of lipase and oxydase. 



The proteolytic enzyme of the polymorphonuclear leukocyte has been named 

 leukoprotease by Opie.^ It actively digests denatured blood serum in a neutral or 

 alkaline reaction (0.2 per cent sodium carbonate) but is inactive in the presence of 

 acid (0.2 per cent acetic acid.) In vitro it acts best at 50°-$ 5° C. It may be preserved 

 in 10 per cent formalin and become active again on the removal of the formalin 

 (Jochmann and Ziegler). It is found in those organs which are rich in leukocytes (bone 

 marrow). Most investigators find that its power to digest protein to the peptone and 

 amino acid stage is less than that of trypsin. Its action is only slightly impaired at a 

 temperature of 65° C. 



Opie found that normal blood contains an anti-enzyme for leukoprotease. Its ac- 

 tion is not specific ; the serum from one animal inhibits the leukoprotease of another. 

 The anti-enzyme is destroyed at 75° C. in thirty minutes. Its action is favored or re- 

 tarded by the same amount of alkali or acid that affects leukoprotease. The digestive 

 action of 20 mg. of dried leukocytes is arrested by 2.5 cc. of serum, but in the presence 

 of more enzyme proteolysis takes place. The anti-enzyme does not come down with 

 the globulins or euglobulins but is precipitated by saturated magnesium sulphate. 



There is no evidence that the anti-enzyme is a true antibody. It is antagonistic 

 to trypsin. An increase in the anti-enzyme content of the blood may be brought about 

 by injecting animals with a variety of substances, e.g., extract of dried leukocytes 

 from pus (Jochmann and Kantorowicz), trypsin (Achalme), small doses of chloroform 

 or phosphorus (Opie, Barker, and Dochez), and tissue cells (Braunstein and Kepnow). 



The anti-enzyme activity of the blood can be removed by extraction with fat sol- 

 vents, and experiments seem to show that the enzyme-inhibiting action is due to the 

 presence of compounds of unsaturated, fatty acids (Schwartz, Jobling, and Peterson, 

 etc.). 



Metchnikofif believed that the complement concerned in bacteriolysis was derived 

 from the polymorphonuclear leukocytes and named it "microcytase" ; and that the 

 complement which combined with antibody to produce hemolysis was derived from 

 the macrophages (macrocy tase) . The difference in resistance to heat would seem to 

 separate leukoprotease from these substances. It is held by some that the leukopro- 

 teases play no direct role in the destruction of micro-organisms. Jochmann, Kan- 

 torowicz, and others found the extracted ferments without bactericidal action in 

 vitro. Nevertheless, many workers have seen the bacteria taken up by leukocytes in 

 test-tube experiments, dissolve and disappear. 



THE PROTEOLYTIC ENZYMES OF THE MONOCYTES 



As shown by Opie^ in the earlier stages of an inflammation the exudate, composed 

 chiefly of polymorphonuclear leukocytes, is alkaline, a reaction favorable for the ac- 



' Tschemoruzki, M.: Ztschr.f. phys. Chemie, 75, 216. 1911. 

 ^ Opie, E. L.: Physiol. Rev., 2, 552. 1922. 

 3 Opie, E. L.: J. Exper. Med., 8, 410. 1906. 



