Trained immunity responses across infectious diseases and cancer vaccines

Trained immunity (TRIM), a paradigm-shifting concept in immunology, refers to the long-term functional reprogramming of innate immune cells, enabling enhanced responsiveness to secondary challenges through metabolic and epigenetic remodeling. This phenomenon bridges the gap between innate and adaptive immunity, offering novel strategies for vaccine design that transcend traditional antigen-specific approaches. By exploiting the 'memorylike' properties of monocytes, macrophages, dendritic cells, neutrophils, and natural killer cells, next-generation vaccines aim to achieve broad-spectrum protection, prolonged durability, and heterologous immunity against pathogens and cancers. This review synthesizes recent advances in TRIM research in vaccines, focusing on its mechanisms, translational applications, and future directions in vaccinology.