STUDIES ON CHEMOTAXIS .11. EFFECT ON NEUTROPHILS OF LYSOSOMAL AND OTHER SUBCELLULAR FRACTIONS FROM LEUKOCYTES

'flic chcmotactic activity of intracellular agents from rabbit leukocytes was tested on homologous neutrophils in vitro. Frozen and thawed neutrophils and macrophages are slightly chemotactic for neutrophils in the absence of serum. The addition of normal scrum increases this activity. Tissue culture fluids from neutrophils are active in the absence and even more so in the presence of fresh normal serum. Lysosomal fractions from neutrophils, peritoneal and alveolar macrophages show strong chemotactic activity for neutrophils only in the presence of fresh normal scrum. Post-lysosomal supernatant fractions from neutrophils and alveolar macrophages are chemotactic without fresh serum. Addition of serum docs not appreciably increase this effect. It is therefore suggested that leukocytes release cytotaxins as well as cytotaxigens which attract other leucocytes. The possible significance of the release of such intracellular agents for inflammatory processes is discussed. © 1969 S. Karger AG, Basel.