Research progress of CpG-DNA in regulation of immune system and signal pathway

Abstract

 CpG-DNA is a DNA sequence with immunostimulatory function as the core of unmethylated CpG motif.It includes synthetic oligodeoxynucleotides (CpG-ODN) containing CpG motifs and genomic DNA of lower organisms such as bacteria, viruses, and invertebrates.CpG-DNA as a potential immunostimulatory factor can be recognized by the vertebrate natural immune system, rapid activation of natural immune response. When exposed to microbes, the release of CpG-DNA provides a "dangerous signal" to the body's immune system, triggering a protective immune response to remove foreign pathogens. CpG-DNA activated cell signaling mechanisms include endocytosis of CpG-DNA, specificity with Toll-like receptor 9 (TLR9) and a series of signal cascades that induce the expression of target genes and Feedback by various endogenous factors. This paper reviews the basic concepts of CpG-DNA, the characteristics of TLR9 receptors, the regulation of the immune system and its signaling pathways.