PDCD1 and neoplasm: FLC slice cultures were treated with IgG control mAb, anti-PD-1 mAb, anti-IL-10 mAb, or anti-PD-1 plus anti-IL-10 mAbs for 6 days and tumor cell apoptosis was measured using cleaved caspase 3 (cC3) IHC (Fig. 5A).