Background: The host innate immune system can recognize Pathogen-Associated
Molecular Patterns (PAMPs) through Pattern Recognition Receptors (PRRs), thereby initiating innate
immune responses and subsequent adaptive immune responses. PAMPs can be developed as a
vaccine adjuvant for modulating and optimizing antigen-specific immune responses, especially in
combating viral infections and tumor therapy. Although several PAMP adjuvants have been successfully
developed they are still lacking in general, and many of them are in the preclinical exploration
Objective: This review summarizes the research progress and development direction of PAMP adjuvants,
focusing on their immune mechanisms and clinical applications.
Methods: PubMed, Scopus, and Google Scholar were screened for this information. We highlight
the immune mechanisms and clinical applications of PAMP adjuvants.
Results: Because of the differences in receptor positions, specific immune cells targets, and signaling
pathways, the detailed molecular mechanism and pharmacokinetic properties of one agonist
cannot be fully generalized to another agonist, and each PAMP should be studied separately. In addition,
combination therapy and effective integration of different adjuvants can increase the additional
efficacy of innate and adaptive immune responses.
Conclusion: The mechanisms by which PAMPs exert adjuvant functions are diverse. With continuous
discovery in the future, constant adjustments should be made to build new understandings. At
present, the goal of therapeutic vaccination is to induce T cells that can specifically recognize and
eliminate tumor cells and establish long-term immune memory. Following immune checkpoint modulation
therapy, cancer treatment vaccines may be an option worthy of clinical testing.