Effects of tumour cell culture supernatants on some biochemical activities of macrophages.

The following enzyme activities were measured in cell lysates and supernatants from mouse peritoneal macrophages incubated with products of cultured tumour and other cells: acid phosphatase, beta-D-glucuronidase, N-acetyl-D-glucosaminidase, muramidase (lysozyme), lactic dehydrogenase (supernatant only) and plasminogen activator (supernatant only). There were no noteworthy changes in enzyme activities. Hydrogen peroxide production by appropriately stimulated mouse and/or guinea-pig peritoneal exudate macrophages was variably inhibited by supernatants from some tumour cells and some normal cells. Changes in these biochemical activities of macrophages do not appear to be closely related to the anti-inflammatory activity of tumour cell products.