Self-Assembling DNA Dendrimer for Effective Deliveryof Immunostimulatory CpG DNA to Immune Cells.

DNAdendrimers consisting of several branched DNA units connectedto each other using DNA ligase were quite effective for the deliveryof immunostimulatory CpG DNA to immune cells. Therapeutic applicationof such DNA dendrimers, however, is hampered by the use of the ligase.Here, we report that self-assembling DNA dendrimers with high immunostimulatorypotency can be prepared without DNA ligases. Annealing of DNA consistingof DNA units with elongated adhesive ends resulted in the formationof DNA dendrimers. Atomic force microscopy revealed that the severalpreparations of DNA dendrimers resulted in dendritic structures asdesigned. The cellular uptake of DNA dendrimers by mouse macrophage-likeRAW264.7 cells and subsequent release of tumor necrosis factor-αwere dependent on the structural complexity of the dendrimers. Theseresults indicate that the ligation-free, self-assembling DNA dendrimersare a potent system for the delivery of immunostimulatory CpG DNAto immune cells. [ABSTRACT FROM AUTHOR]