Abstract
During inflammation an increase in the permeability of the blood vessels permits the passage of erythrocytes, leucocytes, serum proteins and fibrinogen. The digestion and absorption of these elements is accomplished by the proteolytic enzymes of the exudate. The simultaneous presence of substances which inhibit proteolysis suggests a study of their behavior, as well as of the rôle of activators and accelerators of enzyme action during inflammation.
The present contribution is an extension of Opie's observations 1 on the proteolytic enzymes of monocytic and P.M.N. exudates. This material was obtained by injecting mineral oil 2 or an aleuronat-starch mixture 3 into the pleural cavity of rabbits. After separation of the cells from the liquid portion of the exudate, they were washed with saline and extracted in distilled water. Proteolytic activity was then measured during autolysis or during digestion of gelatin by Northrop's 4 formol titration method.
It was observed that whereas monocytes contain only one proteinase, pepsin, which is active from pH 2.0 to 5.0, the optimum being at 3.0, the P.M.N. have pepsin, cathepsin and trypsin with optima at pH 3.0, 5.4, and 8.0, respectively. The serous portions of the exudates (S.F.) also differ in that the monocytic type contains a substance inhibiting peptic digestion by the leucocytes, while the P.M.N. enhances this activity. The S.F. of a P.M.N. exudate inhibits the tryptic activity of the corresponding cells, while cells of a monocytic exudate inhibit the tryptic activity of their S.F.
There is also an inhibitory mechanism which concerns the leucocytes themselves. This was first observed by Willstätter, Bamann and Rohdewald, 5 who showed the presence of mutually antagonistic extractable or “lyo”-enzyme and bound or “desmo”-enzyme in the W.B.C. This was confirmed and their presence in both monocytes and P.M.N. cells of inflammatory exudates was demonstrated.
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