Cutting edge: New chimeric NOD2/TLR2 adjuvant drastically increases vaccine immunogenicity.

TLR ligands are critical activators of innate immunity and are being developed as vaccine adjuvants. However, their usefulness in conjunction with NOD-like receptor agonists remains poorly studied. In this study, we evaluated a new ligand that targets both TLR2 and NOD2 receptors. We assessed its ability to enhance dendritic cell maturation in vitro in addition to improving systemic and mucosal immune responses in mice. The chimeric NOD2/TLR2 ligand induced synergistic upregulation of dendritic cell maturation markers, costimulatory molecules, and secretion of proinflammatory cytokines compared with combinations of separate ligands. Furthermore, when coadministered with biodegradable nanoparticles carrying a model Ag, the ligand was able to induce high Ag-specific IgA and IgG titers at both systemic and mucosal sites after parenteral immunizations. These findings point out the potential utility of chimeric molecules TLR/NOD as adjuvants for vaccines to induce systemic and mucosal immune responses.