ISCOMS AND OTHER SAPONIN BASED ADJUVANTS

Saponins are chemically a heterogeneous group of sterol glycosides and triterpene glycosides which are common constituents of plants. One so urce of triterpenoid saponins obtained from the bark of Quillaia sapon aria Molina (the soap bark tree) have been known to cause substantial enhancement of immune responses since the 1920s, Despite their use in animal vaccines, the development of saponin-based formulations for-hum an vaccines has been impeded by their complexity and concerns about to xicity. This review briefly covers the use of saponins for animal vacc ines but focuses mainly on the development of these adjuvants for use in man. important aspects include preparation of purified or highly de fined saponin fractions, improved understanding of the relationships b etween adjuvant activity, toxicity and structure of saponins and formu lation of saponins into structures with reduced toxicity such as ISCOM s, Recent developments in the understanding of cellular interactions, cytokine induction and the in vivo localisation of saponin containing formulations will also be reviewed. (C) 1998 Elsevier Science B.V.