INVITRO AND INVIVO PRODUCTION OF CHEMOTACTIC INHIBITORS BY TUMOR-CELLS

Abstract

The ascites fluid or peritoneal washings of DBA/2 mice bearing the P815 mastocytoma contained a chemotactic factor inactivator (CFI) which inactivated the bacterial chemotactic factor and the chemotactic activity associated with the C3 [3rd complement component] and C5 fragments when assayed on rabbit neutrophils. The amount of CFI was proportional to the number of tumor cells in the peritoneal exudate. The inactivator was also found in tumor cell hemogenates and in culture fluid from tumor cells growing in vitro. The activity was heat-labile but was not affected by protease inhibitors. Its MW was greater than 50,000 daltons, based on Sephadex chromatography and sucrose density gradient ultracentrifugation studies. In C57BL/6 mice, which rejected the mastocytoma, CFI levels decreased in proportion to the decreasing numbers of tumor cells.