Genetic engineering feat coaxes yeast to produce valuable vaccine compound
Yeast could head off supply fears for vaccines ingredient by replacing soapbark tree as source of adjuvant
Yeast has been engineered to perform the complete biosynthesis of QS-21, a potent and highly sought-after saponin-based adjuvant that boosts the immune response to certain vaccines.
The work represents one of the longest biosynthetic pathways ever transplanted into an organism, introducing 38 enzyme-encoding genes from six different species into yeast. The approach promises to enable a scalable, sustainable and cheaper alternative to make QS-21, as well as aid the design of new adjuvants.
Researchers have focused on the soap-like compound QS-21 as a vaccine adjuvant since the late 1990s for its ability to activate the immune system. Currently, it’s the only saponin-based vaccine adjuvant approved for clinical use in commercial vaccines, including ones for shingles, malaria and Covid-19, something which prompted concerns about QS-21 availability during the pandemic.