To examine CTL activities, splenocytes (1.0 × 106/mL) were harvested and then primed in vitro for 1 h in the presence of IL-2 (10 ng/mL). Those cells were incubated with mature DCs (1 × 105/mL) at a ratio of 10:1 in 96-well plates for 3 days to obtain specific-CTL cells. The specific CTLs (effector cells, 5 × 104/mL) were collected and mixed with B16 cells (target cells, 5 × 103/mL) into 96-well plates to give effector/target cells a ratio of 10:1. The cells were treated with various concentrations of AHG for 44 h. The CTL cell cytotoxicity was measured by MTT assay. The activity of CTLs was calculated by the following formula: CTL cell activity (%) = (ODT − (ODS − ODE))/ODT × 100%, where ODT is optical density value of target cells control, ODS is optical density value of test samples and ODE is optical density value of control effector cells.