Figure 1: NFκB knock down HEp 2 cells as well as OSCSCs or Cal 27 tumors induce much higher induction of NK cell cytotoxicity and secretion of IFN-γ when compared to their more differentiated counterparts: NK cells (1X106/ml) were left untreated or treated with IL-2 (1000 units/ml), or anti-CD16 mAb (3μg/ml) or a combination of IL-2 (1000 units/ml) and anti-CD16mAb (3μg/ml) for 12-24 hours before they were added to the following 51Cr labeled tumors; vector alone transfected HEp-2 cells (A), IκB(S32AS36A) transfected HEp2 cells (A), OSCSCs (C), OSCCs (C), Cal 27 (E) and Cal 33 (E) tumors. NK cell cytotoxicity were determined using a standard 4 hour 51Cr release assay, and the lytic units 30/106 were determined using inverse number of effectors required to lyse 30% of the tumor cells X 100. NK cells were also treated as described in Figure 1A and they were either cultured in the absence of tumors or added to vector alone transfected HEp-2 cells (B) and IκB(S32AS36A) transfected HEp2 cells (B), OSCSCs (D), OSCCs (D), Cal 27 (F) and Cal 33 (F) at an effector to target ratio of 1:1. After an overnight culture, supernatants were removed from the cultures and the levels of IFN-γ secretion were determined using specific ELISAs. One of five representative experiments is shown in this figure.