Chidamide and/or decitabine treatment does not impair CTL cytotoxic functions and chidamide inhibits proliferation of activated T cells.

<p>A. Percentage of IFN-γ producing CD8<sup>+</sup> T cells activated by PMA/Ionomycin following treatment with chidamide at various concentrations for 24 h (left), decitabine (Dac), or chidamide/decitabine (right). B. PRAME antigen-specific killing of chidamide treated THP-1 cells by chidamide, decitabine or chidamide/decitabine treated CTLs. C. PBMCs from healthy donors were treated with chidamide, decitabine or chidamide/decitabine at the indicated concentrations. Cells were washed in PBS to remove any residual drugs and suspended in fresh medium, followed by activation with anti-CD3 and anti-CD28 mAbs (1 µg/ml each) at the presence of recombinant human IL-2 (50 IU/ml). PBMCs cultured with only IL-2 were used as control. On day7 of culture, cells in each well were stained with anti-CD8 FITC and anti-CD3 PE, suspended in 500 µl PBS and acquired in flow cytometer for 30 seconds. Dead cells were excluded by gating out high side scatter cells, and number of CD4<sup>+</sup> T cells (CD3<sup>+</sup>CD8<sup>−</sup>) and CD8<sup>+</sup> T cells (CD3<sup>+</sup>CD8<sup>+</sup>) were divided by that of control CD4<sup>+</sup> or CD8<sup>+</sup> T cells to obtain expansion folds. For combined treatment with chidamide and decitabine in A and B, CTLs were treated with chidamide at 1 µM for 24 h, in combination to decitabine (250 nM) supplemented in culture media twice for 48 h at 24 h interval. In B, chidamide treated THP-1 cells (1 µM for 24 h) were used as target cells, and an E/T ratio of 20/1 was used. *<i>P</i><0.05, **<i>P</i><0.01.</p>