Polyethyleneimine-modified Laminarin nanoparticles enhance antigen delivery to lymph nodes by inducing transient inflammatory responses at the injection site

nanoparticles (CLam/OVA) exhibit potent adjuvant effects. However, it is still unclear how the administration of CLam/OVA affects cell mobilization, the interactions between immune cells in the body, and the transportation of draining lymph nodes. Therefore, the present study aimed to investigate how CLam/OVA enhanced and modulated vaccine-induced immune responses. Results indicate that following CLam/OVA injection, the injection site secretes IL-6, TNF-α, and IFN-γ, forming a transient, adjuvant-induced inflammatory microenvironment. Concurrently, macrophages and dendritic cells are recruited and activated at the site of injection. Subsequently, antigen-loaded dendritic cells homing to lymph nodes drive follicular helper T cells differentiation, germinal center responses, and memory B cell generation, establishing robust and durable adaptive immunity. In summary, this study not only elucidates the immune adjuvant of CLam/OVA but also provides robust support for the design of novel vaccine adjuvants.