Development and characterization of DEC-205 receptor targeted Potentilla anserina L polysaccharide PLGA nanoparticles as an antigen delivery system to enhance in vitro and in vivo immune responses in mice

Potentilla anserina L polysaccharide (PAP) is known to regulate immunity. Poly(lactic-co-glycolicacid) (PLGA) is a type of drug carrier with biocompatibility and biodegradable USFDA approved polymer, which possesses the advantages of high safety and good sustained-release effect. The DEC205 receptor, a type I membrane protein, is widely distributed on the surface of macrophages and dendritic cells (DCs) and plays a key role in antigen recognition and presentation. In this study, we prepared Potentilla anserina L polysaccharide PLGA nanoparticles targeting DEC205 receptor (DEC205-PAPP) and characterized the nanoparticles with regards to their effects on immune activation in vitro and in vivo. In vitro, DEC205-PAPP promoted the uptake activity of macrophages and increased the secretion of NO and cytokines (IFN-gamma, IL-4, IL-6, and GM-CSF), up-regulated the expression of CD80+, CD86+. In vivo, DEC205-PAPP elevated the immune organ index, induced DC maturation, promoted T lymphocyte proliferation and differentiation, and increased the levels of antigen-specific IgG antibody and cy-tokines (IFN-gamma, IL-4), which prolonged the residence time of the OVA antigen in the immune organs and the lymph nodes. In conclusion, DEC205-PAPP had a slow-release effect, induced humoral and cellular immune responses, and could potentially be used as an effective antigen-targeted delivery system.