Research progress in vaccine adjuvant CpG ODN

CpG ODN, a synthetic oligodeoxynucleotide containing CpG motifs, is a TLR9 agonist as it could be recognized by Toll-like receptor 9 (TLR9) expressed on the membranes of B cells, dendritic cells, monocytes and macrophages. CpG ODN is the kind of vaccine adjuvant that promotes Th1 immune responses and enhances the immunogenicity of vaccines with high safety, showing promising prospects in the prevention and treatment of infections, tumors and allergic diseases. This review mainly focuses on the introduction, classification and structure features, immune mechanism, safety and clinical application of CpG ODN as vaccine adjuvant in order to provide references for further researches and application of CpG ODN as immune adjuvant. Key words: Immune adjuvant; CpG ODN; Vaccine; Immune response