Fig 1: NK cells and CD8+ T cells are responsible for IL-15 mediated tumor control and tumor cell killing. (A) Reduction in GFP+ area over time for three independent experiments, with 624-MEL tumor cells that produce IL-15 (gray lines) and 624-MEL cells that do not produce IL-15 (black lines) and that were co-cultured with PBLs that were respectively not depleted, CD4 depleted, CD8 depleted or innate immune cell depleted. The GFP area was measured using the IncuCyte Zoom live cell imaging system (n = 3). (B) Expression of activation markers CD134, CD137, PD-1 and CD16 on CD3- CD56+ NK cells (upper row), CD3+ CD4+ T cells (middle row) and CD3+ CD8+ T cells (lower row) measured in flow cytometry at 72 h in co-culture (n = 5). The number of asterisks in the figure indicates the statistical significance as follows: *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.
Fig 2: IL -15 stimulates tumor cell killing and modulates the immune cell composition. (A) Relative spheroid cell killing as measured as reduction in GFP+ area over time using the IncuCyte Zoom live cell imaging system for spheroids generated with 624-MEL-GFP cells and treated with the indicated cytokines as mean ± SEM (n = 3). (B) Percentage of spheroid killing for the different conditions. Each dot represents the result of an independent experiment, while the dotted line shows the mean of these experiments (n = 3). (C) Distribution of cell subsets within PBLs, defined as CD3+ CD4+ and CD3+ CD8+ T cells, CD3- CD56+ NK cells and cells that are not identified by CD3 or CD56 (rest fraction) for the indicated conditions, 2 and 7 days after the start of the co-culture (n = 3). The number of asterisks in the figure indicates the statistical significance as follows: **p < 0.01, ***p < 0.001.
Fig 3: Genetic IL-15-delivery modulates the immune cell composition and activation. (A) Distribution of cell subsets within PBLs, defined as CD3+ CD4+ and CD3+ CD8+ T cells, CD3− CD56+ NK cells and cells that are not identified by CD3 or CD56 (rest fraction) for the indicated conditions, 5, 7 and 10 days after the start of the co-culture (n = 3). (B) Expression of activation markers CD134, CD137, PD-1 and CD16 on CD3- CD56+ NK cells (upper panel), CD3+ CD4+ T cells (middle panel) and CD3+ CD8+ T cells (lower panel) measured in flow cytometry at 48 h in co-culture (n = 9). (C) Heatmap showing the differential modulation of immune cell composition and activation marker compared to the expression detected in the control condition during a week in co-culture (n = 3). The number of asterisks in the figure indicates the statistical significance as follows: *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.
Fig 4: NK cells and CD8+ T cells are responsible for IL-15 mediated tumor control and tumor cell killing. Expression of the activation markers CD134, CD137, PD-1 and CD16 on (A) CD3- CD56+ NK cells after CD4 and CD8 cell depletion (B) CD3+ CD4+ T cells after CD8 and innate immune cell depletion and (C) CD3+ CD8+ T cells after CD4 and innate immune cell depletion measured in flow cytometry at 72 h co-culture (n = 5). The number of asterisks in the figure indicates the statistical significance as follows: *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.
Fig 5: Genetic IL-15-delivery stimulates immune cell-mediated tumor cell killing. (A) Flow cytometry histograms showing the production of IL-15 after lentiviral transduction of 624-MEL-GFP cells. (B) Concentration of IL-15 in supernatants of 624-MEL-GFP cells that were lentivirally transduced to express IL-15. (C) The graph on the left shows relative spheroid cell killing over time as measured using the IncuCyte Zoom live cell imaging system for spheroids generated with 624-MEL-GFP cells that were lentivirally transduced with IL-15 encoding or control vector as mean ± SEM (n = 9). The graph on the right shows percentages of spheroid killing. Each dot represents the result of an independent experiment, while the line shows the mean of these experiments (n = 9). The number of asterisks in the figure indicates the statistical significance as follows: ***p < 0.001.
Supplier Page from Abcam for Human IL-15 ELISA Kit