Adjuvant activity of chitosan-modified Cynanchum auriculatum Royle ex Wight polysaccharide liposomal nanospheres.

Cynanchum auriculatum Royle ex Wight polysaccharide (CRPS) is an active component with immunoregulatory activity, but its immune enhancement effect lacks targeting and slow-release properties. This study developed a novel polysaccharide-encapsulated liposome carrier, CS-C-O-Lip. This carrier was constructed by loading CRPS and ovalbumin (OVA) into the lipid core, and then modifying the surface of the liposome with carboxymethyl chitosan (CS). CS-C-O-Lip carrier exhibited favorable biocompatibility and immunoadjuvant activity. CS-C-O-Lip can effectively activate macrophages through the TLR4-MyD88-TRAF6-NF-κB signaling pathway, promoting M1 macrophage polarization and nitric oxide (NO) release. Additionally, the CS-C-O-Lip can elicit an effective and sustained cellular immune response as well as a humoral immune response to induce dendritic cell maturation as well as proliferation and differentiation of T lymphocytes in vivo simultaneously. This study provides a foundational basis for the development of liposome vaccines and novel immunomodulatory drugs.