Induction of myeloid colony-stimulating activity in murine monocyte tumor cell lines by macrophage activators and in a T-cell line by concanavalin A.

Certain fibrosarcoma lines in culture and the WEHI-3 myelomonocytic leukemia cell line have previously been shown to secrete myeloid colony-stimulating activity (CSA) spontaneously. We describe here other hematopoietic tumor cell lines in which CSA is either produced constitutively or inducible by immunostimulators. CSA production in macrophage and monocyte tumor lines is induced by lipopolysaccharide, zymosan, Mycobacterium strain Bacillus Calmette-Guérin, tuberculin purified protein-derivative preparation from mycobacteria, and dextran sulfate. Myeloma, mastocytoma, and T-lymphoma lines do not produce CSA with or without these agents. In contrast, the T-lymphocyte mitogen concanavalin A (but not phytohemagglutinin) induces CSA synthesis in one of seven T-lymphomas tested. In most cases induction of CSA is correlated with conditions of cell growth inhibition by the immunomodulators. However, other drugs that cause cytostasis or cytotoxicity do not lead to CSA production. Leukemic cells thus may retain sensitivity to normal regulatory events with resultant effects on host hematopoietic cell functions.