Our laboratory previously described the strategy of fusing chemokine receptor ligands to antigens in order to generate immunogenic DNA vaccines. In the present study, we produced mouse β-2 defensin (mBD2) fusion proteins using both ovalbumin (OVA) and gp100 as model antigens. Superior cross-presentation by dendritic cells (DC) was observed for mBD2 fused antigens over unfused antigens in vitro. In vivo, we observed significant increases in the expansion of adoptively transferred antigen-specific MHC class I, but not class II-restricted T cells after immunization with mBD2 fused antigen over antigen alone. This enhanced expansion of class I restricted T cells was Toll-like receptor 4 (TLR4) dependent, but CC chemokine receptor 6 (CCR6) independent. Superior tumor resistance was observed for mBD2-fusion protein vaccines, compared to unfused antigen, in both B16-OVA and B16 tumor models. These data suggest that production of mBD2 fusion proteins is feasible and that the vaccines facilitate in vivo expansion of adoptively transferred T cells through a TLR4-dependent mechanism.
Published by Elsevier Ltd.