Macrophage proteinase and inflammation: the production of chemotactic activity from the fifth complement by macrophage proteinase.

TLDR: What is possibly an important mechanism by which leukocytes accumulate in chronic inflammatory areas is described, namely, that macrophage proteinase could, from C5, produce C5a which attracts more macrophages and PMN to the site.

Abstract: When the activation of complement proceeds through its fifth component (C5), a chemotactic fragment (C5a) is released (1–3) which attracts both macrophages and polymorphonuclear leukocytes (PMN). 4 Proteolytic enzymes such as trypsin and PMN neutral proteinase also release C5a from C5 (2–4). This report shows that an acid-acting proteinase from both macrophages and lung (a tissue rich in macrophages) (5–7) could do likewise. It therefore describes what is possibly an important mechanism by which leukocytes accumulate in chronic inflammatory areas, namely, that macrophage proteinase could, from C5, produce C5a which attracts more macrophages and PMN to the site. Two sources of macrophage proteinase were used in these experiments. The acid-acting proteinase was partially purified from beef lung by the method of Dannenberg and Smith (5, 6), and further purified on CM-Sephadex columns. Homogenates of either peritoneal or pulmonary macrophages from rabbits also served as a source of this proteinase (7).