AS15 adjuvant (AS15)

AS15 is a complex vaccine adjuvant system developed by GlaxoSmithKline (GSK) that combines several immunostimulatory components, notably MPL (a TLR4 agonist), QS-21 (a saponin), and CpG oligodeoxynucleotide (a TLR9 agonist), designed to induce strong TH1-polarized immune responses and promote both humoral and cellular immunity. It has been primarily evaluated in the context of cancer immunotherapies—especially as part of investigational vaccines targeting tumor antigens (such as MAGE-A3). The system enhances the activation of antigen-presenting cells, increases cytokine production, and promotes robust T cell and antibody responses. AS15 does not correspond to a single molecular target or receptor, but rather engages multiple immunological pathways to amplify vaccine-induced immune responses[5][6][1].

Other names

Adjuvant System AS15GSK AS15

AS15 exerts its effects by activating pattern recognition receptors (TLR4 by MPL, TLR9 by CpG, and pathways impacted by QS-21 such as NLRP3/caspase 1) Induces strong TH1-biased immune response, robust T cell (including CD8+ cytotoxic) and antibody responses Activates dendritic cells and other innate immune cells, increases antigen presentation and cross-presentation pathways[5][1][3][6]