Improved T cell function after celecoxib-treatment. A) The amount of 51Cr released from lysed radiolabeled AB1 target cells was determined to compare cytolytic activity of splenocytes isolated from naïve mice (n = 4) tumour-bearing mice (n = 5) and DC-treated mice (n = 4). To determine the inhibitory effect of MDSC in the spleen, splenocytes from mice receiving control diet or celecoxib diet were co-cultured with splenocytes of DC-treated mice (the number of DC-treated splenocytes was equal in all conditions 150.000 cells/well). Percentage of lysis was calculated using the formula: corrected % lysis = 100 × (experimental release - spontaneous release [target cell incubated in medium alone])/(maximum release - spontaneous release). Splenocytes from DC-treated mice were significantly better capable of lysing tumour cells compared to naïve (p < 0.0001) and tumour-bearing mice (p < 0.0001). The addition of splenocytes from a tumour-bearing mice treated with control diet significantly reduced the lytic capacity of splenocytes from DC-treated mice (p = 0.0002) whereas the addition of splenocytes from tumour-bearing mice treated with celecoxib diet did not affect the lytic capacity of splenocytes from DC-treated mice (p = 0.887). B) Percentages of IFN-γ+ CD8+ cells within the spleen were determined by intracellular FACs staining. DC-treatment significantly improved IFN-γ production by CD8+ cells compared to naïve mice (p < 0.0001) and tumour-bearing mice (p = 0.001). Conditions as described above. C) IFN-γ/Granzyme B production by CD8+ cells was measured by intracellular FACs staining revealing a significant difference between naïve (p < 0.0001) and tumour-bearing mice(p < 0.0001) compared to CD8+ cells in the spleen of DC-treated mice.