Starfish, Asterias amurensis and Asterina pectinifera, as potential sources of Th1 immunity-stimulating adjuvants

Saponin is the generic name of steroid or triterpene glycosides, and the capacities of some saponins to stimulate both Th1 immune response and production of cytotoxic T cells are useful as vaccine components against intracellular pathogens. Because saponins have been found commonly in starfish, we assessed the potential of starfish, Asterias amurensis and Asterina pectinifera, as adjuvant sources. Crude starfish saponins had hemolytic activities (EC(50)=10 to 100 µg/ml) and thin layer chromatography indicated heterogeneity of their constituents. When starfish saponis were subcutaneously injected into mice with ovalbumin (OVA), OVA-specific IgG, especially IgG2a instead of IgG1 was produced in mouse blood, suggesting starfish saponins stimulated Th1 type immunity and they were potential sources of new adjuvants.