A semi-synthetic triterpene glycoside, derived from the naturally occurring saponins. GPI-0100 functions as an adjuvant when given as part of a vaccine preparation to improve the immunogenicity of antigens such as proteins, carbohydrates. GPI-0100 containing vaccines have been used with both viral and tumor antigens to elicit a Type 1 helper T cell response for those diseases in which a cytotoxic T lymphocyte (CTL) response is desired. Check foractive clinical trials using this agent.