Trained immunity induction by vaccines adjuvants

Recent studies have revealed that cells of the innate immune system can adapt to previous insults (such as infections) and build a de-facto innate immune memory termed trained immunity. This process enables enhanced responses to homologous or heterologous microbial stimuli and is primarily driven by long-lasting epigenetic remodeling coupled with metabolic reprogramming. Vaccine adjuvants are well recognized for their ability to amplify adaptive immune responses by stimulation of antigen-presenting cells, making them a critical component of modern vaccine design. There is increasing evidence suggesting that certain adjuvants can also induce trained immunity, highlighting their ability to enhance vaccine efficacy beyond classical adaptive immune responses. This emerging concept provides new opportunities for antigen selection and adjuvant development with higher immunogenicity in future vaccines.