IL2 and melanoma: After isolating mNK cells from bulk splenocytes of WT and p35 k/o mice and activating them ex vivo with IL2, we cocultured them with the B16F10 murine melanoma cell line at different E:T ratios and observed a significant increase in NK cell–mediated cytotoxicity by p35 k/o mNK cells relative to the WT control (Fig. 3B).