Adjuvants are molecules added to vaccines to help them work better by stimulating a stronger immune response. This approach to boosting immunity has been around for decades—drug developers added aluminum salts to diphtheria and tetanus vaccines as early as the 1930s to create robust, long-lasting immune protection against these diseases.
A team of MIT researchers has developed the next generation of vaccine adjuvants: a nanoparticle that gives antibody production after immunization a big boost. The study appears in the journal Science Immunology.
"We started looking at this particular formulation and found that it was incredibly potent, better than almost anything else we had tried," commented Darrell Irvine, who led the study. The findings presented by Irvine's team could help expand the number of approved vaccine adjuvants that are currently available. In a series of animal studies, the researchers found that their nanoparticles showed remarkable protective effects after the administration of HIV, diphtheria, and influenza vaccines.
The new adjuvant technology is powered by two molecules: saponin (a plant extract) and a toll-like receptor agonist called MPLA. These molecules latch on to receptors on immune cells and ignite inflammation, and this is a critical step towards creating 'immune memory' against a pathogen.
Interestingly, the adjuvant also accelerates the path of vaccines to the lymph nodes. According to the experts, time is of the essence once a vaccine is injected into the body because the antigen begins degrading gradually. "The sooner a B cell can see that antigen, the more likely it's fully intact so that B cells are targeting the structure as it will be present on the native virus," commented Irvine.
The team is currently integrating their adjuvant technology into future COVID-19 vaccines.