Thymoquinone, the active ingredient of Nigella sativa seeds, enhances survival and activity of antigen-specific CD8-positive T cells in vitro

Recent preclinical and clinical studies provide evidence that adoptive transfer of in vitro activated T cells can results in significant antitumour responses in vivo upon acquisition of certain survival and homing properties during in vitro activation. Based on recent studies showing in vivo antioxidant effects of thymoquinone (TQ), the active ingredient of Nigella sativa seeds, this study aims to determine whether or not TQ can increase survival and sustain the expression of the homing receptor CD62L in antigen-specific T cells in vitro. The results showed that stimulation of OT-1 (transgenic CD8+) T cells with OVA antigen resulted in activation, as shown by a decrease in the surface expression of CD62L which coincided with significant apoptosis measured three and five days after antigen stimulation. Addition of low concentrations of TQ during CD8+ T-cell activation resulted in enhanced survival of the activated T cells and sustained expression of CD62L. These effects coincided with enhancement in the capability of CD8+ T cells to produce the effector cytokine interferon-γ (IFNγ). These results suggest that TQ has a beneficial effect in conditioning T cells in vitro for adoptive T-cell therapy against cancer and infectious disease.