More modern uses of saponins in biotechnology are as adjuvants in vaccines: Quil A and its derivative QS-21, isolated from the bark of Quillaja saponaria Molina, to stimulate both the Th1 immune response and the production of cytotoxic T-lymphocytes (CTLs) against exogenous antigens make them ideal for use in subunit vaccines and vaccines directed against intracellular pathogens as well as for therapeutic cancer vaccines but with the aforementioned side-effects of hemolysis.
The key components of ISCOMs are the Quillaja saponins, which are derived from the bark of the Chilean soap-bark tree Quillaja saponaria Molina.