Kupffer cells cytotoxicity against hepatoma cells is related to nitric oxide

We have previously demonstrated that rat resting macrophages have cytotoxicity against tumor cells. In the current study we have performed an in vitro experiment to explore the mechanism of Kupffer cells-mediated cytotoxicity against hepatomas. The coculture of tumor cells with Kupffer cells (derived from rat livers) stimulated syngeneic and allogeneic Kupffer cells to produce nitric oxide. Kupffer cell-mediated cytotoxicity was paralleled to the amount of nitric oxide and was abolished by the addition of NG-monomethyl-L-arginine. The ability to stimulate Kupffer cells to produce nitric oxide resided on the membranous fragment of tumor cells.