INHIBITION OF CELLULAR DIVISION OF A MURINE MACROPHAGE TUMOR BY MACROPHAGE-ACTIVATING AGENTS

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  • 1 January 1982
    • journal article
    • research article
    • Vol. 42  (5) , 1850-1855
Abstract
Although the murine reticulum cell sarcoma M5076 is highly malignant in vivo, in vitro it displays many of the functional characteristics of an activated macrophage, such as phagocytosis and tumor cytotoxicity. The effect of macrophage-activating agents on the function and growth of M5076 cells was studied. Exposure of M5076 tumor cells to substances that activate normal macrophages to the tumoricidal state rapidly and irreversibly induced cessation of cellular division. The treated tumor cells retained the same characteristics as those of untreated M5076 cells in vitro with respect to viability and the activated macrophage functions of phagocytosis and tumor cytotoxicity. Even after a short exposure to lipopolysaccharide, the ability of M5076 cells injected i.v. into syngeneic mice to form tumor nodules was greatly reduced. A higly malignant tumor of macrophage origin, M5076, apparently can be induced to cease cellular division while retaining the functional attributes of an activated macrophage. The exposure of M5076 to macrophage-activating agents may result in the induction of terminal differentiation of this tumor.