IL2 and melanoma: In vitro, RES induced a dose-dependent reduction of NXS2 (murine neuroblastoma) and M21 (human melanoma) cell proliferation, mostly due to cytostatic rather than cytotoxic events, that was mirrored by an anti-proliferative effect on mouse splenocytes and human PBMCs induced to proliferate with Concanavalin A (ConA) and Phytohemagglutinin (PHA)/IL-2, respectively, and by reduced ability of effector cells to lyse target cancer cells by antibody dependent cellular cytotoxicity (ADCC).