Effects of daidzein on the activities of CTLs (A, B) and NK cells (C, D) in adult female B6C3F1 mice. Values represent the mean ± SE derived from 7-8 animals. Statistical analysis was conducted as described. (A, C) Mice were maintained on a soy-based diet (Reg) and gavaged with daidzein at the 6 mg/kg dose, and (B, D) mice were maintained on a phytoestrogen-free diet (SF) and gavaged with daidzein at the 20 mg/kg dose. The vehicle was 0.2% methylcellulose/0.1% Tween 80. CTL = cytotoxic T lymphocyte; NK = natural killer cells. VHF = females exposed to vehicle; DZF = females exposed to daidzein. N=7-8.