Efficient delivery of immunostimulatory DNA to mouse and human immune cells through the construction of polypod-like structured DNA

Investigation of mouse macrophage-like RAW264.7 cells showed that the immunostimulatory activity of CpG DNA is increased by formation of polypod-like structured DNA (polypodna), an assembly consisting of three or more oligodeoxynucleotides. To apply CpG polypodna to immunotherapy, its activity was examined in murine dendritic DC2.4 cells, splenic macrophages, and bone marrow-derived dendritic cells (BMDCs). In all cell types, increasing the pod number increased the cellular uptake of DNA and cytokine release. No significant release of cytokines was observed in macrophages lacking Toll-like receptor 9. Similar results were obtained after intradermal injection of polypodna. The polypodna preparations produced significantly higher amounts of interferon a in human peripheral blood mononuclear cells (PBMCs) compared with single-stranded DNA. The conditioned medium of hexapodna-treated human PBMCs effectively inhibited the activity of a hepatitis C virus subgenomic replicon reporter system. These results indicate that polypodna preparations are useful as an immunostimulator. From the Clinical Editor: This study demonstrates the utility of polypoid-like structured DNA (polypodna) preparations as potent immunostimulators in a murine model. (C) 2014 Elsevier Inc. All rights reserved.