Nature’s booster: adjuvant derived from marine sponges stimulates immune response in protein-based COVID-19 vaccines

Although vaccines developed over the COVID-19 pandemic have been highly effective, vaccine ‘boosts’ are still needed to stimulate and direct patients’ immune responses to maintain vaccine effectiveness. In a new publication from ACS Infectious Diseases, researchers utilized an αGC-derived adjuvant to stimulate immune responses in mice, resulting in a 25-fold increase in neutralizing antibody response.

As a result of the COVID-19 pandemic, vaccine development has seen considerable acceleration. Although only one COVID-19 vaccine that has been approved by the FDA currently uses a protein-base method for immunization, most inoculations utilize some kind of protein involvement to stimulate an immune response in the patient.

Vaccines employing proteins contain adjuvants – components that enhance the scale and endurance of the immune response elicited by the vaccine. In this study, an adjuvant called galactosylceramide (αGC) – derived from marine sponges and used in numerous other experimental vaccines – was investigated to improve the immune response of a COVID-19 protein-based vaccine.

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Four analogues of αGC were developed and administered with an experimental vaccine to mice and the resulting immune response tracked over a 35-day period. In this period, the mice received three doses of the analogue-combined vaccine before day 29 and were then monitored until day 35. Two aspects which were monitored closely were antibody and T-cell responses. The added αGC adjuvant did not significantly impact T-cell levels; however, all four αGC analogues elicited a significant increase in antibody response in the inoculated mice.

Incorporation of αGC evoked a ‘robust neutralizing antibody response’ in the mice. After three immunizations, one analogue improved neutralizing antibody response approximately 5.5-fold and another elicited a response that was 25 times greater than the vaccine in isolation.

Although this work is in the early stages of development, the results from the study are encouraging for the use of αGC adjuvants for future COVID-19 inoculations and also demonstrates the value of αGC adjuvants for use in the wider field.

Source: Eureka Press Release: https://www.eurekalert.org/news-releases/962940