Antigen-specific T cell activation through targeted delivery of in-situ generated antigen and calcium ionophore to enhance antitumor immunotherapy.

Recent advances in adoptive T-cell therapy have delivered impressive therapeutic outcomes by instigating enduring anti-tumor responses. Nonetheless, achieving specific T-cell activation remains a challenge due to several factors. Some cancer cells evade T-cell recognition due to the scarcity of tumor-specific T cells and deficiencies in antigen processing or major histocompatibility complex (MHC) presentation. Notably underestimated is the impact of waning T-cell receptor (TCR) expression and the constrained formation of immune synapses (IS) between dendritic cells (DCs) and T cells, impairing T-cell activation. Addressing these complexities, we introduce a pioneering approach featuring the deployment of a gel implant. This implant establishes an on-site antigen reservoir, efficiently targets DCs in lymph nodes, and facilitates calcium ion (Ca) delivery. Engineered with controlled swelling, poroelasticity, and resilience, the gel is suitable for surgical implantation. Its ample encapsulation capacity accommodates both photosensitizers and nanoparticles. Upon in situ photothermal irradiation, the gel generates tumor-specific antigens. Furthermore, cationic albumin nanoparticles (cNPs) co-loaded with monophosphoryl lipid A (MPLA) and ionomycin are released, guiding antigens to tumor-draining lymph nodes for DCs maturation. This meticulous process fosters the formation of IS thereby amplifying antigen-specific T-cell activation.