DIGESTION OF THE 5TH COMPONENT OF COMPLEMENT BY LEUKOCYTE ENZYMES - SEQUENTIAL GENERATION OF CHEMOTACTIC ACTIVITIES FOR LEUKOCYTES AND FOR TUMOR-CELLS

Abstract

Leukocytes contain within their lysosomal granules enzymatic activity that will generate from C5 [complement component 5] chemotactic activity for leukocytes (neutrophils) and tumor (Walker [rat] carcinosarcoma) cells. Similar activity was found in phagocytic supernatant fluids from neutrophils and in purified preparations of the leukocyte neutral porteases elastase and cathepsin G. While leukotactic activities can be generated from C3 or C5 only C5 serves as a source for generation of the chemotactic activity for tumor cells. The C5-related chemotactic activities generated by leukocyte proteases are time-dependent: leukotactic activity appears early, then disappears and is replaced by chemotactic activity for tumor cells. The generation of these chemotactic activities from C5 is blocked by prior treatment of leukocyte preparations with the neutral protease inhibitor Trasylol. The demonstration that enzyme activities from leukocytes have the ability to generate tumor cell chemotactic factors from C5 suggests a possible mechanism by which the development of metastatic lesions may be promoted at sites of tissue injury or inflammation.