The effect of Echinacea purpurea, Astragalus membranaceus and Glycyrrhiza glabra on CD69 expression and immune cell activation in humans - Brush, J; Mendenhall, E; Guggenheim, A; Chan, T; Connelly, E; Soumyanath, A; Buresh, R; Barrett, R; Zwickey, H (Phytother Res, 2006)