Table 2. Increased ratios of IL-6 to IFN-γ secretion in NK resistant UCLA-OSCCs when compared to NK sensitive UCLA-OSCSCs.
| Tumor cells | +/− Immune cells | GM-CSF | IL-8 | VEGF | IL-6 | IFN-γ | |
| pg/ml | pg/ml | pg/ml | pg/ml | pg/ml | Ratio IL-6/IFN-γ | ||
| UCLA-OSCCs | − NK | 20 | 438.4 | 620.4 | 126 | 0.8 | - |
| UCLA-OSCCs | + NK (−IL-2) | 148.8 | 723.2 | 784 | 215 | 1 | 215 |
| UCLA-OSCCs | + NK (+IL-2) | 565.8 | 282.2 | 145.5 | 179 | 820 | 0.22 |
| UCLA-OSCSCs | − NK | 0.1 | 23.3 | 1745 | 13 | 1 | - |
| UCLA-OSCSCs | + NK (−IL-2) | 25 | 66.7 | 1256 | 65 | 1 | 12.5 |
| UCLA-OSCSCs | + NK (+IL-2) | 1068.9 | 12.5 | 158 | 12 | 1730.6 | 0.007 |
| No tumors | + NK (−IL-2) | 0.8 | 0 | 0.4 | 11 | 0.6 | 18 |
| No tumors | + NK (+IL-2) | 403.2 | 3.14 | 8.6 | 13 | 290 | 0.44 |
NK cells (1×106/ml) were left untreated or treated with IL-2 (1000 units/ml) for 12–24 hours before NK cells (1×105/ml) were added to primary oral tumors at an effector to target ratio of 1∶1. Tumor cells were each cultured alone or in combination with NK cells as indicated in the table and the supernatants were removed from the cultures after an overnight incubation. The levels of cytokine secretion were determined using antibody coated multiplex microbead immunoassay. For simplification of the table standard deviations are not included and they ranged from 0% to a maximum of 5% of the amount obtained for each cytokine. One of three representative experiments is shown.