Nano-strategy empowering trained immunity in vaccines

Vaccines represent a significant milestone in the history of human medical development and have played an indispensable role in safeguarding public health. The incorporation of nanotechnology holds promise for mitigating the adverse effects of conventional vaccines while concurrently enhancing their immunogenicity. Immune memory is a critical factor in assessing the efficacy and longevity of vaccines. Traditionally, immune memory has been perceived as a function exclusive to the adaptive immune system. However, recent studies have demonstrated that immune memory can also be established within the innate immune system, a phenomenon referred to as trained immunity. This article reviews nanovaccines associated with trained immunity, specifically analyzing the primary nano-strategies that empower trained immunity in vaccines. Such strategies are expected to inform the design of future vaccines that comprehensively induce immune functions. For example, optimizing the physical properties of nanocarriers can significantly improve the transport and utilization of nanoparticles by innate immune cells, while specific antigen release systems can enhance the precision of drug release regarding both location and timing, thereby prolonging the duration of trained immunity. This is anticipated to provide valuable insights for future vaccine designs aimed at inducing comprehensive immune responses.