Mannose-modified erythrocyte membrane-coated Chuanmingshen violaceum polysaccharide PLGA nanoparticles to improve immune responses in mice.

This study developed a poly(lactic-co-glycolic acid) (PLGA) biomimetic nanoparticle (Man-RBC-CVPP) containing Chuanmingshen violaceum polysaccharide (CVP) and coated with a macrophage-targeting mannose receptor (DSPE-PEG-Man) modified RBCM. In vitro experiments demonstrated that Man-RBC-CVPP enhances antigen uptake and immune responses in RAW264.7 cells and can induce an immune response in mouse macrophages by activating the TLR4-mediated NF-κB signaling pathway. In vivo experiments showed that Man-RBC-CVPP promotes the activation of splenic dendritic cells (DCs) by increasing the expression of major histocompatibility complex class II (MHCII), CD80+, and CD86+. Further, it improves the maturation of splenic lymphocytes, increasing the expression of CD4+ and CD8+. It also upregulates the secretion of cytokines, raises serum levels of the specific antibody IgG, and slows the release of OVA at the injection site. In summary, Man-RBC-CVPP can effectively enhance both cellular and humoral immune responses and provide controlled, long-term antigen release.