Cytokines in IL-15 TG/MT tumors and their effects on the ability of human NK cells to kill human breast cancer cells. (A & B) IL-12 and IL-18 are increased in IL-15 TG/MT tumors. (A) IL-12 ELISAs were performed on tumor homogenates from 6 size matched tumors per group. (B) 3 tumors from different mice in each tumor group were pooled (size matched between groups) and assayed for IL-18 cytokine levels via multianalyte protein analysis. (C & D) NK cells isolated from human PBMCs were cultured in IL-2 or IL-15/IL-12/IL-18 for 16 hours before being incubated with CFSE labelled MDA-231 cells for 5 hours in a killing assay. In the demonstration of the gating strategy in C) CD45+ NK cells were first removed from the analysis and then CFSE+ MT cells were selected. 7AAD was used to determine the percentage of the CFSE+ MT cells that were dead. Results at an E:T ratio of 1:10 are displayed (E:T = NKcell:MDA-231). MT alone is included to show spontaneous death levels which were used in the calculation of D. (D) Percent specific lysis of MDA-231 in the killing assay at various E:T ratios. Representative of 2 experiments. *p < 0.05.