ODN M362 - TLR9 Agonist

CpG ODNs are synthetic oligonucleotides that contain unmethylated CpG dinucleotides in particular sequence contexts (CpG motifs) [1]. These CpG motifs are present at a 20-fold greater frequency in bacterial DNA compared to mammalian DNA. CpG ODNs are recognized by Toll-like receptor 9 (TLR9) leading to strong immunostimulatory effects [2].

Three types of stimulatory CpG ODNs have been identified, types A, B and C, which differ in their immune-stimulatory activities [3-4]. Type A CpG ODNs are characterized by a phosphodiester central CpG-containing palindromic motif and a phosphorothioate 3’ poly-G string. They induce high IFN-α production from plasmacytoid dendritic cells (pDC) but are weak stimulators of TLR9-dependent NF-κB signaling. Type B CpG ODNs contain a full phosphorothioate backbone with one or more CpG dinucleotides. They strongly activate B cells but stimulate weakly IFN-α secretion. Type C CpG ODNs combine features of both types A and B. They contain a complete phosphorothioate backbone and a CpG-containing palindromic motif. Type C CpG ODNs induce strong IFN-α production from pDC and B cell stimulation.

ODN M362 is a CpG ODN type C specific for human / murine TLR9 [5].

1. Krieg, A.M. et al., 1995. CpG motifs in bacterial DNA trigger direct B-cell activation. Nature, 374(6522):546-9. 
2. Bauer, S. et al., 2001. Human TLR9 confers responsiveness to bacterial DNA via species-specific CpG motif recognition. PNAS. 98(16):9237-42. 
3. Krug A. et al., 2001. Identification of CpG oligonucleotide sequences with high induction of IFN- alpha/beta in plasmacytoid dendritic cells. Eur J Immunol, 31(7): 2154-63. 
4. Marshall JD. et al., 2005. Superior activity of the type C class of ISS in vitro and in vivo across multiple species. DNA Cell Biol. 24(2):63-72. 
5. Ballas ZK. et al., 2001. Divergent therapeutic and immunologic effects of oligodeoxynucleotides with distinct CpG motifs. J Immunol. 167(9):4878-86.