Population changes in lymphocyte subsets in BALB/c mice fed silk lutein extract daily for 4 weeks. Splenic single cells were isolated and labeled with fluorescently conjugated monoclonal antibodies specific for the mouse B cell markers CD21/35 (A), and the mouse T cell markers CD3 (B), CD4 (C) and CD8 (D). The percentages of lymphocyte subsets were quantitated by Flow cytometry. Values represent means ± SEM. * P < 0.05; ** P < 0.01 compared to the control. SLT10, SLT20; silk lutein extract 10 and 20 mg/kg groups.