Sono-Destructive Polymeric Nanocapsules Enable Spatiotemporal Orchestration of DC-T Cell Crosstalk in Combined In Situ Vaccination and Cytokine Therapy

Antigen-directed T cell cancer immunotherapy is increasingly shifting toward combination regimens with complementary mechanisms to enhance efficacy without exacerbated toxicity. However, rationally designing efficient combination strategies in this realm remains a challenge. Herein, we engineered a sono-destructive and clinically approved β-amino ester random copolymer (PBAE) nanoplatform that integrates sonosensitizers and interleukin-12 (IL-12) to spatially and temporally regulate antitumor immunity. The PBAE polymer features a thioacetal backbone that enables ultrasound (US)-triggered complete fragmentation, allowing for precise and rapid spread of tumor antigens, immunogenic molecules, and a single low dose of IL-12 (one-tenth of the high doses typically used for therapeutic benefit). In a preclinical human papillomavirus (HPV) 16 oncoproteins E6/E7-expressing tumor model, this combination therapy demonstrates superior antitumor efficacy alongside a robust safety profile. Mechanistically, US-mediated in situ vaccination activates multiple subsets of dendritic cells (DCs), including conventional type I DC (cDC1), cDC2, monocyte-derived DCs, and plasmacytoid DCs, enhancing the presentation of released E7 antigens to prime T cells. IL-12 further amplifies the cytotoxic activity of E7-specific CD8⁺ T cells and drives the differentiation of T helper 1 cells, complementing therapeutic effect through increased production of cytotoxic enzymes, and cytokines. This work presents an advanced combination regimen for streamlined cancer immunotherapy.