A CpG-oligodeoxynucleotide (CpG-ODN) for inducing a TLR9 activated immune response, a TLR21 activated immune response or a combination thereof in a host is provided. The CpG-ODN includes one or more copies of the sequences of GTCGTT, one or more copies of the sequences of GTT and one or more copies of the sequences of TTTT, wherein at least one copy of the sequence of GTCGTT is encoded between the sequence of GTT and the sequence of TTTT. Further, an immunogenic composition including the CpG-ODN and a method of inducing immune response by the same are also provided.
