CpG oligonucleotide and α-d-mannose conjugate for efficient delivery into macrophages

For improved intracellular uptake of CpG ODN into macrophages, we developed CpG ODN and mannose conjugate (CpG–Man conjugate) via simple conjugation of α-d-mannose to CpG ODN. CpG–Man conjugate showed greatly enhanced intracellular uptake by 2.1-fold into macrophages, compared to CpG ODN in a TLR-9 receptor-specific manner. In addition, internalized CpG–Man conjugate successfully triggered TNF-α release in macrophages. Taken together, the CpG–Man conjugate can serve as the promising delivery systems of CpG ODN into immune cells as a candidate adjuvant.