Nanovaccines Mediated Subcutis‐to‐Intestine Cascade for Improved Protection against Intestinal Infections

Parenteral vaccines typically can prime systemic humoral immune response, but with limited effects on cellular and mucosal immunity. Here, a subcutis‐to‐intestine cascade for navigating nanovaccines to address this limitation is proposed. This five‐step cascade includes lymph nodes targeting, uptaken by dendritic cells (DCs), cross‐presentation of antigens, increasing CCR9 expression on DCs, and driving CD103+ DCs to mesenteric lymph nodes, in short, the LUCID cascade. Specifically, mesoporous silica nanoparticles are encapsulated with antigen and adjuvant toll‐like receptor 9 agonist cytosine‐phosphate‐guanine oligodeoxynucleotides, and further coated by a lipid bilayer containing all‐trans retinoic acid. The fabricated nanovaccines efficiently process the LUCID cascade to dramatically augment cellular and mucosal immune responses. Importantly, after being vaccinated with Salmonella enterica serovar Typhimurium antigen‐loaded nanovaccine, the mice generate protective immunity against challenge of S. Typhimurium. These findings reveal the efficacy of nanovaccines mediated subcutis‐to‐intestine cascade in simultaneously activating cellular and mucosal immune responses against mucosal infections. This work reports the rational design of a subcutis‐to‐intestine cascade for navigating nanovaccines to simultaneously activate cellular and mucosal immune responses. By processing the cascade in vivo, the subcutaneously injected nanovaccines significantly improve protection against intestinal infections.