Abstract
Background: A key challenge in cancer immunotherapy is that tumor vaccines formulated with conventional aluminum adjuvants often fail to elicit potent cellular immunity and sustained antitumor responses. Glycyrrhizae polysaccharides (NGUP), characterized by significant immunomodulation, multi-target antitumor efficacy, and low toxicity, represent promising candidates for next-generation vaccine adjuvants. Methods: We employed transcriptome analysis, quantitative real-time PCR, and Western blot assays to investigate the mechanism of NGUP in activating bone marrow-derived dendritic cells in vitro. Using confocal microscopy, small animal in vivo imaging, and flow cytometry, we examined the process of tumor antigen-specific T cell response activation by the liposomal vaccine (NGUPL@OVA) in vivo. The efficacy of NGUPL@OVA was evaluated in murine melanoma models (B16-OVA and B16-F10) through immunohistochemistry, immunofluorescence and H&E staining. Results: NGUP activates dendritic cells through the TLR4/MyD88/TRAF6/NF-κB signaling pathway. NGUPL@OVA demonstrates efficient lymph node targeting capacity, significantly enhancing dendritic cell maturation and antigen cross-presentation, thereby promoting robust CD8+ T cell activation and inducing potent cellular immune responses with long-term immunological memory. In both prophylactic and therapeutic settings, NGUPL@OVA exhibits significant melanoma growth inhibition without observable toxic side effects. Conclusions: NGUP as a novel vaccine adjuvant for cancer immunotherapy effectively overcomes key limitations of conventional aluminum adjuvants, including weak induction of cell-mediated immunity and significant adverse effects, while exhibiting superior immune-stimulating properties.