To determine whether IL-15 DCs and IL-4 DCs are capable of modulating NK cell cytotoxic function, NK cells were tested for cytotoxicity against various tumor cell targets (NK-sensitive K562 cells and NK-resistant Daudi cells) following a 48-hr stimulation with autologous IL-15 DCs or IL-4 DCs (Fig 3). This evidence concerns the gene IL4 and neoplasm.