TLR9-activating cholesterol azetidine derivative-assisted therapeutic vaccines for cancer immunotherapy.

Therapeutic cancer vaccines show great promise for de novo induction of antigen-specific T cell responses against tumors. However, weak coordination between innate immune activation and antigen delivery remains a major obstacle to vaccine efficacy. Here, we present a cholesterol azetidine derivative-assisted polymeric carrier, Aze-Chol NP, which stimulates innate immunity and primes tumor-specific CD8(+) T cell responses. Mechanistically, Aze-Chol NP induces maturation and activation of dendritic cells (DCs) through the Toll-like receptor 9 (TLR9) pathway while simultaneously delivering protein or peptide antigens to DCs in lymph nodes. The Aze-Chol NP-based nanovaccines markedly inhibited tumor growth and prolonged survival in melanoma and human papillomavirus tumor models. Moreover, combining the nanovaccine with an anti-PD-L1 antibody produced a strong synergistic effect and long-term immune memory, achieving 80% survival beyond 100 days and complete rejection of tumor cell rechallenge. Overall, our study demonstrates that this TLR9-activating carrier provides an effective and straightforward strategy for developing potent cancer vaccines.