A method of stimulating a TLR9-activated immune response or enhancing a TLR9-activated immune response to an antigen is disclosed herein. TLR9 is the cellular receptor for CpG-ODN, and current developed CpG-ODN has low activity to rabbit TLR9. Here, the method of stimulating TLR9-activated immune response by administering an effective amount of immunogenic composition comprising an antigen and a CpG-ODN comprising GACGTT or AACGTT motif was demonstrated to have potent immunostimulatory activity to rabbit TLR9, and capable of boosting a less toxic and potent antibody response in rabbits.