QS 21

QS-21, an immunostimulatory saponin, could be used as a potent vaccine adjuvant. QS-21 stimulates Th2 humoral and Th1 cell-mediated immune responses through action on antigen presenting cells (APCs) and T cells. QS-21 can activate the NLRP3 inflammasome with subsequent release of caspase-1 dependent cytokines, IL-1β and IL-18[1][2][3].

NLRP3 inflammasome

[1] Fernández-Tejada A, et al. Development of Improved Vaccine Adjuvants Based on the Saponin Natural Product QS-21 through Chemical Synthesis. Acc Chem Res. 2016;49(9):1741-1756. DOI:10.1021/acs.accounts.6b00242
[2] Marty-Roix R, et al. Identification of QS-21 as an Inflammasome-activating Molecular Component of Saponin Adjuvants. J Biol Chem. 2016;291(3):1123-1136 DOI:10.1074/jbc.M115.683011
[3] Lacaille-Dubois MA. Updated insights into the mechanism of action and clinical profile of the immunoadjuvant QS-21: A review. Phytomedicine. 2019;60:152905. DOI:10.1016/j.phymed.2019.152905