Quaternized chitosan-coated liposomes enhance immune responses by co-delivery of antigens and resveratrol

Co-localization of antigens and immunomodulators in the same antigen-presenting cells (APCs) can powerfully activate APCs and enhance immune responses. In this study, the immunomodulator resveratrol (Res) was encapsulated into quaternized chitosan (QCS) - coated liposomes for developing a new nanoparticle delivery system (QCS-Res-LP), and ovalbumin (OVA) was selected as a model antigen and adsorbed on the surface of QCS-Res-LP. The results showed that the particle size of QCS-Res-LP was 96.3 ± 3.52 nm; the PDI value was 0.280 ± 0.010; the Zeta potential was 9.59 ± 0.36 mV. QCS-Res-LP could encapsulate 76.22 ± 1.02 % resveratrol and adsorb 88.2 ± 16.3 % antigen. QCS-Res-LP effectively promoted the co-uptake of antigen and Res by dendritic cells (DCs) with 50-fold greater than resveratrol liposomes (Res-LP). QCS-Res-LP promoted expression levels of CD80, CD86, IL-2, and IL-12 in DCs. QCS-Res-LP did not cause hemolysis. The levels of ovalbumin-specific IgG antibodies and cytokines were significantly increased in mice vaccinated with ovalbumin-absorbed QCS-Res-LP, which induced a mixed Th1/Th2 immune response. In conclusion, these results demonstrated that QCS-coated liposomes enable the co-delivery of antigens and immunomodulators to induce strong and durable immune responses.