The Ability of Chemotactic Factors to Induce Lysosomal Enzyme Release

Abstract

The complement-derived chemotactics factors, C3a, C5a, and C567, as well as the chemotactic factor obtained from culture filtrates of Escherichia coli, induce release of the lysosomal enzymes, β-glucuronidase and lysozyme, from rabbit peritoneal neutrophils. Under the same circumstances, there is little or no release of the cytoplasmic marker, lactic dehydrogenase, indicating that the release is a form of induced secretion. The release occurs to an appreciable extent only when the neutrophils settle on filters of average pore size of 0.60 µm or greater; however, increasing the pore size of the filters from 0.60 to 5 µm does not increase the amount of lysosomal enzyme secretion. The requirement for an appropriate surface suggests that enzyme release by chemotactic factors is a form of induced secretion on non-phagocytosable surfaces studied previously. No statistically significant correlation was found between the chemotactic responsiveness of neutrophils from different rabbits and their ability to give lysosomal enzyme release when stimulated by the same chemotactic factor. This suggests, at least, that a critical step or steps in the biochemical sequence or sequences governing chemotaxis and induced secretion of lysosomal enzymes in neutrophils is different or has a different quantitative importance.