Formulations and mechanisms of action of novel vaccine adjuvants

Abstract

Vaccine adjuvants play a critical role in inducing optimal adaptive immune responses. Vaccine adjuvants can be lipids, metal-based, pathogen-based, and plant-based compounds. Few vaccine adjuvants are licensed for use in human vaccines; however, much more novel adjuvants are patented because they exert functional activity and boost immune response to vaccine antigens. The molecular mechanisms and signaling pathways induced by adjuvants differ according to their category and components. The type of adjuvant also impact the quality and amplitude of induced immune responses whether humoral antibodies or cell-mediated immune responses. Adjuvants also impact antigen-presenting cells, such as dendritic cells, costimulatory molecules expression, and enhance antigen presentation as a prerequisite of proper adaptive immune response. As adjuvants can affect metabolomics profile, their detailed mechanisms of action should be considered for personalized vaccine design. This chapter discusses the current licensed adjuvants, unlicensed discovered patented adjuvants, and details their mechanisms of action and induced signaling pathways.