Adjuvantides

Adjuvantides are substances that enhance the immune response to an antigen. In English, the more common term is adjuvants; adjuvantides is a less common variant or the term used in some languages or contexts. They are employed in vaccines and other immunotherapies to increase immunogenicity, improve antibody formation, and influence the quality and duration of immunity.

Mechanisms: Adjuvantides act through multiple routes. They can create a local inflammatory milieu that recruits antigen-presenting cells, activate innate immune receptors such as toll-like receptors and inflammasomes, and promote uptake and presentation of the antigen by dendritic cells. They may also induce cytokines and co-stimulatory signals that enhance T- and B-cell responses. Some formulations create a depot effect that prolongs antigen exposure.

Applications: They are used to improve protection in prophylactic vaccines and to boost efficacy in therapeutic vaccines and immunotherapies, including cancer vaccines. They are also used in subunit vaccines that lack strong inherent immunogenicity.

Examples: Classic adjuvants include aluminum salts; modern adjuvants include oil-in-water emulsions (e.g., MF59, AS03), liposome- or nanoparticle-based systems, and toll-like receptor agonists (e.g., MPL in AS04, CpG motifs).

Safety and regulation: Adjuvants can cause local reactions and systemic symptoms; safety is evaluated in clinical trials and regulated by authorities such as the FDA and EMA; formulations are optimized to balance efficacy with reactogenicity.

History and research: Adjuvantides have a long history since the early 20th century; ongoing research seeks to tailor immune bias (Th1 vs Th2) and reduce adverse effects, with interest in targeted adjuvants that combine with specific antigens or delivery platforms.