Saponins as vaccine adjuvants.

Naturally occurring triterpene glycosides (saponins) from Quillaja saponaria have considerable adjuvant activity. Adjuvant functions include stimulation of high levels of antibody to T-dependent and T-independent antigens, induction of mouse IgG1, IgG2b, and IgG2a isotypes, and induction of cytotoxic T lymphocyte responses. This article reviews responses due to specific saponins of saponin preparations, effect of formulation, structure/function studies, and use in different preclinical and clinical vaccine applications.