Stimulating macrophage activity in mice and humans by oral administration of quillaja saponin

Quillaja saponin (QS) was examined for its immunostimulating effect on mice and humans after oral administration. Mice fed QS for 24 h significantly increased in chemotactic and phagocytosis activities of peritoneal macrophages. This enhancing effect in both activities continued for 4-d after QS administration. Mice fed QS for 24 h prior to an interperitoneal challenge with Escherichia coli showed a higher survival rate than the control group. Peripheral blood analysis of volunteers showed significant increases in chemotactic and phagocytosis activities after oral administration of QS for 7 d. Furthermore, the volunteers did not show significant changes in immunoglobulin, transaminase, IL-1α, or TNF-α levels, or in serum albumin concentrations. Thus orally administered QS can effectively enhance the immune response through stimulation of macrophages without adverse effects.