QS-21 Adjuvant: Laboratory-Scale Purification Method and Formulation Into Liposomes

Methods Mol Biol. 2017:1494:73-86. doi: 10.1007/978-1-4939-6445-1_5.

Abstract

QS-21, a saponin extracted from the tree Quillaja saponaria Molina, is a vaccine adjuvant which has been shown to elicit robust antibody and cell-mediated immune responses in a variety of preclinical and clinical studies [1]. Its purification from the natural source is a lengthy and difficult process. The commercially available saponin mixture Quil-A® is a fraction of the bark extract containing a variety of saponins, including QS-21. In order to facilitate access to QS-21 at laboratory-scale amounts, we propose here a method of purification of QS-21 starting from Quil-A®. In addition, we describe a protocol to appropriately formulate QS-21 into cholesterol-containing, neutral liposomes which are known to decrease QS-21's hemolytic activity while retaining the adjuvant effect. Methods for the physicochemical characterization of purified QS-21 and of the QS-21/liposome formulations are also described.

Keywords: QS-21; Saponin; Vaccine adjuvant.

MeSH terms

  • Adjuvants, Immunologic* / chemical synthesis
  • Adjuvants, Immunologic* / chemistry
  • Adjuvants, Immunologic* / isolation & purification
  • Adjuvants, Immunologic* / pharmacology
  • Animals
  • Liposomes
  • Mice
  • Saponins* / chemical synthesis
  • Saponins* / chemistry
  • Saponins* / isolation & purification
  • Saponins* / pharmacology

Substances

  • Adjuvants, Immunologic
  • Liposomes
  • Saponins
  • saponin QA-21V1