Abstract
The purpose of this study was to investigate the immuno-stimulatory activity of the high-molecular-weight
fraction (HMWF) of Cynanchum wilfordii (CW) extracts obtained by ultrafiltration in murine macrophage RAW 264.7
cells and to assess its immuno-stimulatory effect in mice. Ultrafiltration was performed with polyethersulfone membranes
(30 kDa cutoff) in a cross-flow filtration system to obtain the HMWF of CW. The results showed that the HMWF
increased the production of various cytokines such as tumor necrosis factor-α, interleukin-6, and nitric oxide in dosedependent
manners. In addition, HMWF treatment increased the relative spleen weight as well as splenocyte proliferation
induced by concanavalin A or bacterial lipopolysaccharide in mice. Natural killer (NK) cell activity in the HMWF-treated
group was significantly increased compared to that in the control group. These results suggest that the HMWF of CW can
support the immune system through secretion of macrophage cytokines, thereby enhancing NK cell activity and murine
splenocyte proliferation.