Glycyrrhiza uralensis Polysaccharide Gold Nanoparticles as Antigen Carriers and Potential Adjuvant to DC Vaccines.

Background: Cervical cancer is the fourth leading cause of death among women worldwide, with human papillomavirus (HPV) identified as a major contributing factor. This study investigates the immunostimulatory activity and antigen delivery efficiency of Glycyrrhiza uralensis polysaccharide gold nanoparticles (GUPS-AuNPs) and assesses the antitumor efficacy of an HPV dendritic cell (DC) vaccine using GUPS-AuNPs as a delivery system. Methods: GUPS-AuNPs were synthesized via a green reduction method and characterized using advanced techniques, including SEM, EDS, TEM, UV, and FT-IR spectroscopy. DCs served as the primary experimental model, with flow cytometry employed to evaluate the immunostimulatory activity and antigen delivery effectiveness of GUPS-AuNPs. Additionally, a TC-1 tumor-bearing mouse model was established to assess the immunostimulatory and antitumor effects of the HPV-DC vaccine facilitated by GUPS-AuNPs. Results: The synthesized GUPS-AuNPs exhibited a particle size of 120.77 ± 3.13 nm, a surface charge of -11.9 ± 2.1 mV, and excellent stability. Flow cytometry analysis demonstrated that GUPS-AuNPs significantly enhanced DC maturation and promoted T cell proliferation. Furthermore, antigen delivery experiments revealed that GUPS-AuNPs improved the antigen capture capabilities of DCs. Confocal imaging confirmed that GUPS-AuNPs extended the intracellular retention time of antigens. In vivo studies showed that the HPV-DC vaccine formulated with GUPS-AuNPs as carriers effectively suppressed tumor growth, elevated the populations of CD4⁺ T and CD8⁺ T cells in the spleen, and induced a robust antigen-specific immune response. Conclusions: GUPS-AuNPs effectively enhance DC maturation and antigen delivery, significantly boosting the adaptive immune response triggered by HPV vaccines and leading to the inhibition of tumor progression. This research introduces GUPS-AuNPs as a novel, safe, and efficient antigen delivery platform with promising potential for vaccine development.