Adjuvant Systems (AS) technologies was first developed by Glasko-Smith-Klein (GSK) in the late 1980s. These are combinations of classical adjuvants – aluminum, oil-in-water emulsions, liposomes, and immunomodulatory molecules. Four AS Systems Adjuvants have been developed so far. AS01 is composed of mono-phosphoryl lipid A, otherwise known as MPL, QS-21, and
