Saponins as Immunoadjuvants
Saponins are very widely distributed in plants (Price et al, 1987), but the one that is used as an adjuvant is extracted from the bark of the South American tree Quillaia saponaria (Dalsgaard, 1978). It is a triterpene glycoside, consisting of the hydrophobic triterpene polycyclic ring, to which is attached two chains of sugars (Fig. 1), which are hydrophilic. This gives the molecule surface-active properties, and saponin is used as a foaming agent in soft drinks. Its potential as an adjuvant was discovered more than 50 years ago (Thibault and Richou, 1936), and it has since become widely used in veterinary vaccines, particularly those against foot-and-mouth disease virus (Dalsgaard, 1978). Recently new impetus has been given to research on saponin by the discovery that it can form small ordered structures, ISCOMS or immunostimulating complexes, with phospholipid, cholesterol, and proteins with a suitable hydrophobic tail such as those extracted from viral envelopes (Morein, 1988 and chapter by Morein in this volume). This chapter reviews what is known of the adjuvant properties of saponin and its mechanism of action.
KeywordsTrypanosoma Cruzi Triterpene Glycoside Rous Sarcoma Virus Adjuvant Activity Polyene Antibiotic
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- Dalsgaard, K., 1978, A study of the isolation and characterization of the saponin Quil A. Evaluation of its adjuvant activity, with a special reference to the application in the vaccination of cattle against foot-and-mouth disease, Acta Vet.Scan., Suppl., 69: 1.Google Scholar
- Thibault, P. and Richou, R., 1936, Sur l’accroissement de l’immunité antitoxique sous l’influence de l’addition de diverses substances a l’antigene (anatoxines diphthérique et tetanique), C.R. Seances Soc. Biol., 121: 718.Google Scholar