Macrophage tumor killing: influence of the local environment

Science  15 Jul 1977:
Vol. 197, Issue 4300, pp. 279-282
DOI: 10.1126/science.327547


Tumor killing by activated macrophages is not a highly determined biologic event, but a relative capability influenced by the local environment. An intrinsic macrophage cytotoxic effector system is modulated by serum and other environmental factors that can either enhance or suppress tumor killing. Activated macrophages kill tumor cells only when a regulating threshold drops to a critically low level.