Immune effects and mechanisms of action of CpG motifs

Bacterial DNA differs from vertebrate DNA in having a much higher content of unmethylated CpG dinucleotides, in particular, base contexts that are termed ‘CpG motifs’. The vertebrate immune system appears to have evolved pattern recognition molecules that recognize ‘CpG motifs’ as foreign, and trigger protective immune responses which are strongly Th1-biased. These responses can be mimicked using synthetic oligodeoxyribonucleotides, which have demonstrated remarkable utility as vaccine adjuvants and as immunotherapeutics for treatment of cancer and allergic diseases.