ROLE OF NITRIC-OXIDE IN CELL-MEDIATED TUMOR-CYTOTOXICITY

Strong and increasing evidence shows that nitric oxide (NO) contribute s 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 c ell-mediated immune responses to neoplastic cells in vitro and in vivo . The cytokine-inducible nitric oxide synthase (NOS) seems to mainly b e implicated in the cytotoxic activity of almost all the effector cell s involved in tumor cell killing. The cytotoxic actions of NO against tumor cells appear to be related mainly to inhibition of several heme- containing enzymes of the mitochondrial electron transport complex and the citric acid cycle.