CpG Oligodeoxynucleotides as Immune System Modulators CpG oligodeoxynucleotides, also known as CpG ODNs, are short segments of synthetic DNA containing an unmethylated cytosine-phosphate-guanine (CpG) dinucleotide motif. In vertebrates, methylation of CpG dinucleotides is common except in certain genomic regions like CpG islands. The immune system recognizes unmethylated CpG motifs as a signature of bacterial and viral DNA, secreting cytokines to...