Generation of Th1-polarizing Dendritic Cells Using the TLR7/8 Agonist CL075

In this paper, we describe a new method for preparation of human dendritic cells (DCs) that secrete bioactive IL-12(p70) using synthetic immunostimulatory compounds as TLR7/8 agonists. Monocyte-derived DCs were generated using a procedure that provided mature cells within 3 d. Several maturation mixtures that contained various cytokines, IFN-gamma, different TLR agonists, and PGE(2) were compared for impact on cell recovery, phenotype, cytokine secretion, migration, and lymphocyte activation. Mixtures that included the TLR7/8 agonists R848 or CL075, combined with the TLR3 agonist polyinosinic:polycytidylic acid, yielded 3-d mature DCs that secreted high levels of IL-12(p70), showed strong chemotaxis to CCR7 ligands, and had a positive costimulatory potential. They also had excellent capacity to activate NK cells, effectively polarized CD4(+) and CD8(+) T cells to secrete IFN-gamma and to induce T cell-mediated cytotoxic function. Thereby, mature DCs prepared within 3 d using such maturation mixtures displayed optimal functions required for vaccine development.