Dual-Engineered Dendritic Cell Derived Small Extracellular Vesicles Couple T Cell Priming with Checkpoint Reprogramming for Synergistic Immunotherapy

Immunotherapy has transformed cancer treatment, yet cell-based therapies remain complex and costly, and immune checkpoint blockade (ICB) agents often suffer from limited stability and poor T-cell selectivity. Here, we develop an engineered dendritic cell-derived small extracellular vesicle (DC-sEV) nanoplatform for combinatorial immunotherapy via in situ T-cell activation and checkpoint reprogramming. DC-sEVs preserve intrinsic dendritic-cell immunobiology, enabling antigen presentation and potent T-cell activation. We further integrate high-efficiency cargo loading and membrane functionalization to selectively deliver ICB payloads to T cells, achieving dual reprogramming that sustains effector function and amplifies antitumor immunity. This approach reduced cancer cell viability to 44.05% in vitro and produced 82.12% tumor growth inhibition in vivo, establishing DC-sEVs as a targeted, scalable cell-free immunotherapy platform. HIGHLIGHTSO_LIDC-sEVs preserve antigen presentation, T-cell activation, and lymph node targeting C_LIO_LIChirality-assisted loading with pH-responsive functionalization enables efficient cytosolic delivery while maintaining membrane bioactivity C_LIO_LIEngineered DC-sEVs combine in situ T-cell priming and PD-1 silencing to enhance effector function C_LIO_LIIn situ T-cell reprogramming drives potent antitumor efficacy and favorable tumor microenvironment remodeling C_LI GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=110 SRC="FIGDIR/small/717283v1_ufig1.gif" ALT="Figure 1"> View larger version (50K): org.highwire.dtl.DTLVardef@e3b05org.highwire.dtl.DTLVardef@44febcorg.highwire.dtl.DTLVardef@1b00479org.highwire.dtl.DTLVardef@f5db2a_HPS_FORMAT_FIGEXP M_FIG C_FIG