TLR9 and tetanus: Thus, this CTL epitope was fused to a universal T-helper epitope, either a synthetic pan HLA-DR epitope (PADRE) or a natural tetanus (Tet) sequence, with or without CpG 7909, a toll-like receptor 9 (TLR9) synthetic oligonucleotide antagonist, and the fusion showed positive immunogenicity profiles [123].