Vanilloid receptor 1 agonists, capsaicin and resiniferatoxin, induce efficient anti-viral CTL responses by increasing MHC-restricted antigen presentation (78.29)

Abstract

Abstract DCs, like the sensory neurons, express vanilloid receptor 1 (VR1). Here we demonstrate that VR1 agonists, capsaicin (CP) and resiniferatoxin (RTX), increase MHC-restricted antigen presentation in DCs. Treatment of DCs, that were infected with recombinant vaccinia virus (VV) expressing OVA (VV-OVA), with CP or RTX significantly increased MHC class I-restricted OVA presentation. In accordance with the in vitro results, oral administration of CP into VV-OVA-infected mice significantly enhanced MHC class I-restricted OVA presentation, and consequently elicited potent OVA-specific CTL activity compared to untreated controls. The effects of VR1 agonists on the exogenous antigen presentation were also examined in DCs. CP and RTX enhanced MHC class I-restricted, but not MHC class II-restricted, presentation of exogenous OVA. CP and RTX did not affect phagocytic activity, the expression level of total MHC molecules and co-stimulatory molecules on DC, suggesting that they enhance the intracellular processing events of phagocytosed antigens. These results demonstrate that VR1 agonists preferentially increase MHC class I-restricted antigen processing pathways. The present study also shows that oral consumption of CP, a common component of pungent foods, could enhance the efficacy of DC-based anti-viral and anti-tumor vaccines.