Regulation of anti-tumor immune responses

Abstract

Nitric oxide has a dual role in both regulation of immune homeostatsis and in responses to pathogens. It is therefore not surprising that a similar duality exists in the response against neoplastic cells. At the same time as NO can exert cytotoxicityagainst tumor cells it can also inhibit immune reactivity against these cells. The following chapter will recapitulate the basal roles of NO in immune homestasis and immune reactivity against pathogens followed by a more detailed review of the role of NO in immune reactivity against tumors. In experimental therapy against tumors, the positive effects of NO can thus be manipulated by administration of NO donors or by inducing NO secretion from innate immune cells. On the other hand, nhibition of NO release by NOS inhibitors or by inhibition of molecules upstream of NOS induction can boost adaptive immune responses mainly by T cells.