Combined use of toll-like receptor agonists and prostaglandin E2 in the FastDC model:: Rapid generation of human monocyte-derived dendritic cells capable of migration and IL-12p70 production

Phenotypical maturation, IL-12p70 production and migration upon chemokine receptor CCR7 ligation are currently proposed as requirements for the use of human monocyte-derived dendritic cells (DC) in antitumoral vaccination. We have previously described a short-term protocol for DC generation from monocytes including stimulation with TNF-alpha, IL-1 beta and PGE(2) (FastDC). These conventional FastDC are mature, migrate in response to CCR7 ligation and effectively stimulate autologeous T cells in vitro, but are deficient in IL-12p70 production. Here, conventional FastDC were compared to FastDC activated with different TLR ligands. High levels of IL-12p70 were induced by combined activation of FastDC with TLR4 and TLR7/8 ligands. IL-12 secretion could be maximized by additional T cell-derived stimulation. However, TLR-stimulated FastDC failed to migrate upon CCR7 ligation, independent of additional activation with CD40 ligand and IFN-gamma. The presence of PGE(2) during TLR ligation fully restored migratory capacity of FastDC, but left IL-12p70 production and activation of tumor antigen-specific cytotoxic T cells unaffected, challenging previous findings obtained with standard 7-day monocyte-derived DC. The FastDC model thus not only represents an effective tool for antitumoral vaccination, but may also provide novel insights into human DC biology. (c) 2008 Elsevier B.V. All rights reserved.