The assembly of a short linear natural cytosine-phosphate-guanine DNA into dendritic structures and its effect on immunostimulatory activity.
DNA containing unmethylated CpG dinucleotides, or CpG motifs, (CpG DNA) has been explored as a therapeutic agent, owing to its potent immunostimulatory activity. A previous study showing that Y-shaped (Y-) CpG DNA has a high immunostimulatory activity compared with single- or double stranded CpG DNA suggests the possibility that CpG DNA in a more complicated structure is a stronger activator of the immune system. In the present study, dendrimer-like DNA (DL-DNA) was prepared by ligating Y-DNA monomers. The DL-DNA of the second or third generation with 12 or 24 highly potent CpG motifs in one unit, respectively, were designed and successfully prepared for the first time. These DL-DNAs induced greater amounts of tumor necrosis factor-alpha and interleukin-6 from RAW264.7 macrophage-like cells than did a mixture of Y-DNA with the same sequences as the corresponding DL-DNA. DL-DNA was more efficiently taken up by RAW264.7 cells than Y-DNA, but the increase was lower than that exhibited by the levels of cytokine release. These results suggest that the dendritic structure formation is a potential approach to increasing the immunostimulatory activity of CpG DNA without any modifications of the chemical structure of the natural phosphodiester DNA.
Rattanakiat
Sakulrat
S
Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
Nishikawa
Makiya
M
Funabashi
Hisakage
H
Luo
Dan
D
Takakura
Yoshinobu
Y
D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D000818:Animals; D002460:Cell Line; D018899:CpG Islands; D016207:Cytokines / Q000276:immunology*; D004247:DNA / Q000008:administration & dosage* / Q000138:chemical synthesis* / Q000648:ultrastructure; D050091:Dendrimers / Q000008:administration & dosage / Q000737:chemistry; D008264:Macrophages / Q000187:drug effects / Q000276:immunology*; D051381:Rats
D000276:Adjuvants, Immunologic; D016207:Cytokines; D050091:Dendrimers; D004247:DNA