DEC-205-mediated liposomal delivery of OVA and Eucommia polysaccharides: dendritic cell targeting, adjuvant activity, and TLR-NF-κB-mediated immune enhancement

DEC-205 monoclonal antibodies were assembled on the surface of liposomes carrying OVA antigen and Eucommia ulmoides polysaccharides to generate a delivery system with targeted dendritic cells. The liposomal encapsulation process of Eucommia ulmoides polysaccharide was optimized, and DEC-205-EUPS-OVA-LP was synthesized under optimal conditions to improve the utility of Eucommia ulmoides polysaccharide. Meanwhile, the physicochemical properties and adjuvant activity of the delivery system were evaluated in vitro.The optimized liposomes exhibited uniform particle size (<220 nm), suitable zeta potential (-11 to -15 mV), good dispersity (PDI < 0.3), and favorable encapsulation efficiency. 39.1 μg/mL DEC-205-EUPS-OVA-LP can promote the proliferation of dendritic cells and promote their antigen uptake. Furthermore, DEC-205-EUPS-OVA-LP significantly enhanced the secretion of IL-2, IL-6, IFN-γ, and TNF-α and elevated the expression of the co-stimulatory molecules CD80, CD86, and MHC-II on dendritic cells. High-throughput sequencing and Western blot results showed that DEC-205-EUPS-OVA-LP upregulated immune-related genes in dendritic cells and enhanced immunity via the TLR-NF-κB pathway. In summary, DEC-205-EUPS-OVA-LP targets dendritic cells to facilitate antigen uptake, processing, and presentation, promotes dendritic cell maturation, and enhances the immune response.