Figure 3.

Enhancement of cytotoxic activity of human NK cells at various concentrations of bamboo leaf extract at different E/T ratios (n = 8/group). Suspensions of effector NK cells were added to target K562 cells at E/T ratios of 5:1, 25:1 or 50:1. (A) Cytotoxic activity for control, PBS (closed circle); IL-2 at 1 μg ml⁻¹ (open square); IL-2 at 10 μg ml⁻¹ (closed square). (B) That for bamboo leaf extracts at 1 μg ml⁻¹ (closed triangle), 10 μg ml⁻¹ (open diamond) and 100 μg ml⁻¹ (closed diamond). (C) That for unfractionated bamboo leaf extract at 100 μg ml⁻¹ (closed diamond), F-I at 100 μg ml⁻¹ (closed triangle), F-II at 100 μg ml⁻¹ (closed square), F-III at 100 μg ml⁻¹ (open square), 1,3-β-glucanase-digested F-I at 100 μg ml⁻¹ (open triangle) and PBS (closed circle). Values represent means ± SD. **P < 0.01 and *P < 0.05 versus controls.