Role of nitric oxide in cell-mediated tumor cytotoxicity.

Strong and increasing evidence shows that nitric oxide (NO) contributes to immune function, and in particular to 'non-specific host defense'. The aim of the present review was to focus the current understanding of the role of NO as a biochemical effector of L-arginine-dependent cell-mediated immune responses to neoplastic cells in vitro and in vivo. The cytokine-inducible nitric oxide synthase (NOS) seems to mainly be implicated in the cytotoxic activity of almost all the effector cells involved in tumor cell killing.