Sequential Barrier Navigation by Yeast β-Glucan-Engineered Liposomal Nanovaccines Potentiates Oral Melanoma Immunotherapy

Dongyang Wu,1,2,* Chenyang Jiang,1,2,* Hui Li,1,2,* Kairui Zhu,1,2 Wenyan Liu,1 Yang Guo,1,2 Weili Liu,1,2 Rui Yan,1,2 Zuoyuan Liang,1,2 Xiaoke Liu,1,2 Zhixin Zhao,1,2 Hongfang Sun,1,2 Yan Liang1,21Department of Pharmacy, Shandong Medical and Pharmaceutical University Hospital, Shandong Medical and Pharmaceutical University, Binzhou, Shandong, 256603, People’s Republic of China; 2Department of Biochemistry and Molecular Biology, Shandong Medical and Pharmaceutical University, Yantai, Shandong, 264003, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yan Liang; Hongfang Sun, Department of Pharmacy, Shandong Medical and Pharmaceutical University Hospital, Shandong Medical and Pharmaceutical University, Binzhou, Shandong, 256603, People’s Republic of China, Email [email protected]; [email protected]: Orally delivered protein antigens face gastrointestinal degradation and inefficient transport through mucus, across the intestinal epithelium, and into antigen-presenting cells (APCs). To address these barriers, we developed YGB@OVA/PBA-C-LIPs, an ovalbumin (OVA)-loaded cationic liposomal nanovaccine coated with yeast β-glucan (YGB) and functionalized with phenylboronic acid (PBA).Methods: We characterized the physicochemical properties of YGB@OVA/PBA-C-LIPs and evaluated their mucus and epithelial transport, macrophage uptake, OVA cross-presentation, and immune activation in vitro. Laminarin competition was used to assess β-glucan-sensitive uptake. Gastrointestinal residence, immune responses, antitumor activity, and tolerability were examined after oral administration to B16-OVA-bearing mice.Results: YGB@OVA/PBA-C-LIPs averaged 127.5 ± 0.8 nm in diameter and had an OVA encapsulation efficiency of 83.17 ± 1.98%, with no marked size increase over 12 days at 4 °C. They improved transport through a simulated mucus layer and across the Caco-2/Raji B model and increased RAW264.7 macrophage uptake; laminarin attenuated this advantage, supporting a β-glucan-sensitive component of uptake. The formulation also increased surface CD80 and H-2Kb-SIINFEKL levels in DC2.4 cells and IFN-γ release in DC2.4-splenocyte co-cultures. After a single oral dose, the Cy7-labeled formulation remained detectable in the abdomen at 72 h. Repeated dosing reduced tumor weight by 75.0% versus untreated tumor-bearing controls (0.36 ± 0.11 versus 1.44 ± 0.23 g) and increased serum OVA-specific IgG reactivity to 3.8 times the control value. Major-organ histology showed no evident abnormalities.Conclusion: The YGB/PBA dual-functionalized formulation combined gastrointestinal protection and mucosal transport with enhanced antigen presentation by APCs, improving immune responses and tumor control in the B16-OVA model. Validation with clinically relevant tumor antigens is needed to establish broader therapeutic relevance.Keywords: oral nanovaccine, sequential barrier navigation, yeast β-glucan, phenylboronic acid, antigen-presenting cells, melanoma immunotherapy