Some biochemical aspects of the immune macrophage.

Some of the biochemical properties of mouse peritoneal macrophages immune to were characterised. Total cellular protein of immune cells exceeded that of normal phagocytes by 1·85 times. The activities of 7 hydrolytic enzymes, acid phosphatase, β-glucuronidase, Cathepsin D, lysozyme, BPN-ase, MN esterase and aryl sulphatase were measured in lysed cell suspensions and monolayer cultures. Immune macrophages possessed substantially higher levels of these enzymes than did normal cells. No one enzyme was significantly more associated with the development of cellular immunity than another. Resting immune macrophages consumed significantly less oxygen than normal cells required but were twice as active in glycolysis. ATP levels, in agreement, were 5 times higher in normal macrophages whereas ATP-ase activities were equivalent. Normal macrophages were approximately twice as active in protein synthesis measured by the incorporation of C L-glycine by monolayer cultures than were immune cells. These results were considered in the light of known morphological differences between the 2 cells noted at the ultrastructural level.