Glycosylated Carbonated Apatite Particles for Macrophage‐Targeted Delivery of CpG Oligodeoxynucleotides From Streptococcus thermophilus Enhance Immu

ABSTRACT

Immunostimulatory CpG oligodeoxynucleotides (CpG‐ODNs) are potent activators of innate immunity with promising applications in human and veterinary medicine. We previously developed carbonate apatite‐based oligonucleotide particles (ODNcaps) for oral delivery, which are efficiently taken up by macrophages in jejunal Peyer's patches. To enhance macrophage‐specific targeting, we introduced glycan modifications to ODNcaps, exploiting carbohydrate‐binding receptors on macrophages. In this study, glycosylated ODNcaps were synthesized through N‐acetylglucosamine (GlcNAc) conjugation and evaluated for cellular uptake and immunostimulatory activity in mouse peritoneal macrophages. Uptake efficiency was quantified using fluorescently labeled CpG‐ODNs, and immune activation was assessed by IL‐6 mRNA expression and IL‐6 secretion. GlcNAc‐modified ODNcaps showed markedly higher uptake and induced the strongest IL‐6 responses at both transcriptional and protein levels compared with non‐glycosylated controls. These results demonstrate that glycosylation is a simple yet effective strategy to improve macrophage targeting and immunostimulation by CpG‐ODNs. Beyond murine models, this platform may hold promise for oral or mucosal immune modulation in livestock such as cattle, poultry, and swine, offering a novel approach to enhance antigen‐presenting cell activation and strengthen mucosal immunity in animal production.