Nanoliposomal PD-1 antagonist target tumor-draining lymph nodes to revitalize T cells and improve anti-tumor effect in hepatocellular carcinoma.

Background: Tumor-draining lymph nodes (TdLNs) are pivotal in tumor immunotherapy, including the action of immune checkpoint inhibitors such as PD-1/PD-L1 blockade. However, fully harnessing the therapeutic potential of TdLNs to improve clinical outcomes remains a significant challenge.

Methods: A PD-1 antagonist peptide-conjugated nanoliposome (LPs) was developed to improve lymph node targeting and therapeutic efficacy. The biodistribution, lymph node accumulation, and safety of LPs were assessed using imaging, histological, and systemic analyses. Immunodeficient mouse models and lymphadenectomy were employed to confirm the mechanistic reliance on adaptive immunity and TdLNs. Bulk RNA sequencing and multicolor flow cytometry were used to investigate TdLNs function and assess CD8⁺ T cell immune responses in TdLNs and the tumor microenvironment (TME).

Results: LPs demonstrated optimal physicochemical properties, including ideal size, serum stability, and precise TdLNs accumulation, peaking at 3 h post-administration. In two immunocompetent HCC models, LPs treatment significantly suppressed tumor growth while remodeling the TME-enhancing CD8⁺ T cell infiltration and reducing myeloid-derived suppressor cells. Transcriptomic analysis of TdLNs revealed significant upregulation of lipid storage/metabolism pathways and immune activation signatures. Immune profiling validated LPs-mediated expansion of precursor-exhausted and tissue-resident memory-like CD8⁺ T cell subsets in both TdLNs and tumors, accompanied by reduced exhaustion markers. Crucially, the therapeutic efficacy was completely abrogated in immunodeficient mice and following surgical lymphadenectomy, confirming the essential role of adaptive immunity and functional TdLNs in LPs' mechanism of action.

Conclusions: Targeting PD-1 on T cells within TdLNs effectively boosts anti-tumor immunity. The modified LPs offer a potent strategy to enhance the efficacy of cancer immunotherapy.