Improving effects of protein-based COVID-19 vaccines

In a new study in ACS Infectious Diseases, researchers report a substance that boosted the immune response to an experimental COVID-19 shot in mice by 25 times, compared to injection with the vaccine alone. Researchers have found that molecules derived from α-galactosylceramide (αGC), a compound from marine sponges, can act as adjuvants by stimulating a small population of immune cells important for defending the body against viral infections.

The team made four analogs of αGC and added each to an experimental vaccine containing a piece of SARS-CoV-2's spike protein, which the virus uses to infect cells. The researchers gave mice three injections over 29 days and tracked their immune response out to 35 days. To measure the effects of the adjuvants, they looked at various aspects of immune function, including two ways the immune system eliminates pathogens: through antibodies, which are immune proteins that latch onto an invader, and T cells, which kill diseased cells.

None of the four meaningfully enhanced the T cell response, but all of them produced antibodies with a much greater capacity for interfering with the virus. The analog called αGC-CPOEt led to the production of antibodies with the greatest neutralizing capacity-25 times greater than what the vaccine could elicit without an adjuvant.

Ref:

Rui Luo et al,A new iNKT-cell agonist-adjuvanted SARS-CoV-2 subunit vaccine elicits robust neutralizing antibody responses,ACS Infectious Diseases, DOI: 10.1021/acsinfecdis.2c00296