NCIt definition : A synthetic oligodeoxynucleotide, containing unmethylated CpG motifs derived from
bacterial DNA, with immunostimulatory activities. A CpG oligodeoxynucleotide (CpG
ODN) binds to and activates a Toll-like receptor 9 (TLR9) and is taken up into cells
by endocytosis; once internalized, it may activate numerous signaling transduction
pathways resulting in the release of multiple cytokines. Through activation of TLR9,
a CpG ODN can directly stimulate B-lymphocytes, dendritic and NK cells, resulting
in an increase in innate immunity and antibody-dependant cell cytotoxicity (ADCC).
Additionally, a CpG ODN can indirectly modulate T-cell responses, through the release
of cytokines (IL-12 and IFN gamma), to induce a preferential shift to the Th1 (helper)
phenotype resulting in enhanced CD8 cellular cytotoxicity.;