Selective modification of rat peritoneal macrophage lysosomal hydrolases by inflammatory stimuli

Lysosomal acid hydrolases were surveyed in elicited and non-elicited rat peritoneal macrophages to determine the types of enzymes present and optimal assay conditions. Adherent peritoneal cells (primarily macrophages) were cultured 24 hours prior to use. Intracellular distribution of enzymes was determined by differential centrifugation of whole cell homogenates into nuclear, cytoplasmic, and lysosomal fractions. The acid glycosidase, acid phosphatase, acid protease, and lysozyme were largely sedimentable in the lysosomal fraction. Much enzyme activity was latent, being activated by addition of Triton X-100. Chymotrypsin-like protease activity in cell fractions was apparently due to low level mast cell contamination. Elicited macrophages had elevated total cell protein as compared to non-elicited cells, but changes in intracellular enzyme levels were selective depending on the enzyme and the stimulus used to elicit macrophages. Thioglycollate-elicited cells showed elevations of most acid hydrolases compared to non-elicited cells, whereas enzyme levels in zymosan-elicited cells were similar to those in non-elicited cells. All elicited cells showed marked decreases in total cellular alpha-D-mannosidase and alpha-L-fucosidase compared to non-elicited cells. Intracellular lysozyme levels also varied between different rat strains. Cultured macrophages exhibited increasing intracellular levels and extracellular secretion of acid hydrolases, especially extracellular lysozyme (10-25 mug/10(6) cells/day), over 72 hours. No significant intra- or extracellular elastinolytic activity was detected.