TLR agonists as vaccine adjuvants: comparison of CpG ODN and Resiquimod (R-848)

TLR ligands that mimic pathogen associated molecular patterns and activate immune cells via Toll-like receptors (TLRs) are being developed for use in humans as therapy against a variety of diseases as well as vaccine adjuvants. These include imidazoquinoline compounds such as Imiquimod and Resiquimod (R-848) that bind to TLR7 and 8, as well as CpG oligodeoxynucleotides (CpG ODN) that bind to TLR9. This study was aimed at comparing CpG ODN and R-848 for their potential use as vaccine adjuvants and to determine whether there are additive or synergistic effects when they are used together. Using HBsAg as a model antigen in mice, we show CpG ODN to be superior to R-848 for augmenting both humoral and cell mediated immune responses.