A T cell leukemia line produces factor(s) that render rat neutrophils cytotoxic

Proteose-peptone-induced intraperitoneal neutrophils from rats were activated in terms of tumor cytotoxicity by pretreatment with culture supernatants from a human T cell leukemia line, Jurkat (culture sup). Culture sup-treated neutrophils showed cytotoxicity against various tumor cell lines. The cytotoxicity of culture sup-treated neutrophils was dependent on the number of neutrophils and the concentration of culture sup. Cytostasis by activated neutrophils was observed very early in the assay incubation period (within 6 hr), but cytolysis first occurred at 24 hr after the start of incubation. Factor(s) in culture sup responsible for the activation of cytotoxic neutrophils were stable to temperature and pH treatments, and their molecular weight was higher than 10,000. The responsible factor(s) for activation of cytotoxic neutrophils were different from interleukin-2, serum-derived factor, and bacterial lipopolysaccharide.