Immunological adjuvant (Adjuvant)

Immunological adjuvants are diverse substances added to vaccine or immunotherapeutic formulations to enhance, broaden, or prolong antigen-specific immune responses beyond what is achieved with antigen alone. They function by engaging and modulating the innate immune system (e.g., via PRRs such as TLRs and NLRs), recruiting immune cells to the injection site, and promoting antigen uptake, presentation, and memory formation. This term encompasses a variety of molecular entities, delivery systems, and mechanisms—including mineral salts (alum), PRR agonists (TLR ligands, MPLA), nanoparticles, and emulsion-based agents—rather than any single molecular structure or physiologically defined receptor. Their use is foundational for modern vaccine efficacy, but "immunological adjuvant" itself does not denote a unique or specific molecular target for drug development.

Other names

Immunologic adjuvantvaccine adjuvantimmune adjuvant

Local activation of innate immune response at injection site; Engagement of pattern recognition receptors (PRRs), e.g., TLRs, NLRs; Formation of depot for prolonged antigen release; Enhancement of antigen uptake and presentation via antigen-presenting cells (APCs); Activation and recruitment of immune cell populations; Induction of cytokine and chemokine release; Promotion of Th1, Th2, or Th17 adaptive responses via polarization