Vaccines containing a saponin and a sterol

Abstract

A novel adjuvant composition comprising a sterol (e.g., cholesterol, β-sitosterol, stigmasterol, ergosterol, and ergocalciferol) and saponin fraction (e.g., QS21, also known as QA21) in the form of an immunostimulating complex, or ISCOM, is disclosed. QS21 is an immunologically active saponin fraction having adjuvant activity derived from the bark of Quillaja Saponaria Molina. Previous attempts in the prior art to prepare ISCOMs comprising QS21 were unsuccessful. Thus, the instant application discloses the first successful attempt to prepare ISCOMs comprising purified QS21. Small unilamelar liposomes containing cholesterol, in the absence of any detergent, were prepared, followed by the addition of an aqueous solution of QS21. The claimed compositions will prove useful in the preparation of highly immunogenic vaccine compositions.

Dependencies are inferred from the claim text.