Adrenergic modulation of dendritic cell cancer vaccine in a mouse model: role of dendritic cell maturation.

The aim of the present study was to evaluate the role of beta2-adrenergic receptors (beta2-ARs) in the outcome of a dendritic cell (DC)-based cancer vaccine in the murine E.G7-ovalbumin (OVA) model. We found that unlike the beta2-AR expressed on antigen loaded DCs, beta2-ARs expressed in the site of DCs inoculation may influence the efficacy of the antitumor response. Intradermal injection of Staphylococcus aureus peptidoglycan along with the beta2-AR-specific antagonist ICI 118,551 increased the local innate cytokine response in tumor-bearing mice. When the adoptive transfer of immature DCs loaded with OVA followed this skin preconditioning, the antitumor response was increased and tumor growth was significantly reduced. Surprisingly, when OVA-loaded mature DCs were used, the effect of the skin preconditioning was the opposite and tumor growth was similar to that observed in control, nonimmunized mice. The extent of the antitumor response on transfer of immature or mature DCs was mediated by a different migration in the draining lymph nodes and by a distinct recruitment of endogenous DCs that resulted in a modulation of the OVA-specific cytotoxic T lymphocyte response. The unexpected tolerogenic effect exerted by mature DCs on skin preconditioning was apparently mediated by the expression of a distinctive pattern of cytokines and of the suppressive enzyme indoleamine 2, 3-dioxygenase in draining lymph nodes. In conclusion, we found that beta2-ARs inhibition along with toll-like receptor2 activation at the site of cancer vaccination may either enhance the resulting antitumor response or be tolerogenic in dependence of the maturation state of the transferred DCs.