The science of adjuvants

Abstract

Adjuvants are substances that boost the immunogenicity of vaccines. However, most successful vaccines have been derived empirically and are capable of inducing robust T- and B-cell immunity without any adjuvant additives. Emerging evidence suggests that such live vaccines induce innate immune activation via a range of stimuli, including ligands specific for Toll-like receptors, which, in effect, serve as their own adjuvants. In contrast to these live vaccines, subunit vaccines need to be supplemented with adjuvants to boost their immunogenicity. However, there is a paucity of licensed adjuvants for clinical use and, thus, there is a critical need to develop safe and effective adjuvants. In this context, recent advances in innate immunity are beginning to offer new insights into how empiric vaccines and adjuvants mediate their efficacy. In this article, we review the latest progress and emerging concepts in adjuvant development, which includes novel findings in innate immune biology and their impact on vaccinology.

Keywords::

• adjuvant
• CpG
• C- type lectin-like receptors
• dendritic cell
• flagellin
• innate immunity
• monophosphoryl lipid A
• nucleotide oligomerization domain-like receptor
• RIG-I-like receptor
• signaling
• Toll-like receptor

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.