ODN 1668 sodium, a class B CpG ODN (oligodeoxynucleotide), is a TLR-9 agonist. ODN 1668 sodium has strong immune regulatory properties, can enhance the level of antibody IgG2 subtype, promote the immune response of T cells and B cells, and can be used in the study of vaccine adjuvants. In addition, CpG ODN 1668 sodium induces an antimicrobial immune response via a CaTLR9 dependent pathway in groupers. Sequence: 5'-tccatgacgttcctgatgct-3’[1][2][3][4].