Adjuvant (AS03 or MF59) (N/A)

AS03 and MF59 are oil-in-water emulsion adjuvants used to enhance the immune response to vaccines. AS03 contains squalene, α-tocopherol (vitamin E), and polysorbate 80, while MF59 primarily contains squalene. They act by creating a depot effect, stimulating local inflammation, recruiting innate immune cells, and inducing cytokine/chemokine production. AS03 tends to induce a Th2-biased response, while MF59 elicits a more balanced Th1/Th2 response. Both adjuvants increase antibody titers and improve vaccine immunogenicity, particularly in elderly populations. They do not act through well-defined pattern recognition receptors like TLRs, but rather through NLRP3-independent ASC activation and MyD88-dependent/TLR-independent signaling pathways.

Other names

AS03MF59Oil-in-water emulsion adjuvantα-tocopherol, squalene, and polysorbate 80 emulsionSqualene emulsion

Depot effect at the injection site, stimulation of local tissue inflammation, recruitment of innate immune cells, cytokine/chemokine induction, enhanced antigen presentation.