Optimal culture conditions for the generation of natural killer cell-induced dendritic cells for cancer immunotherapy

Dendritic cell(DC)-based vaccines continue to be considered an attractive tool for cancer immunotherapy.DCs require an additional signal from the environment or other immune cells to polarize the development of immune responses toward T helper 1(Th1)or Th2 responses.DCs play a role in natural killer(NK)cell activation,and NK cells are also able to activate and induce the maturation of DCs.We investigated the types of NK cells that can induce the maturation and enhanced function of DCs and the conditions under which these interactions occur.DCs that were activated by resting NK cells in the presence of inflammatory cytokines exhibited increased expression of several costimulatory molecules and an enhanced ability to produce IL-12p70.NK cell-stimulated DCs potently induced Th1 polarization and exhibited the ability to generate tumor antigen-specific cytotoxic T lymphocyte responses.Our data demonstrate that functional DCs can be generated by coculturing immature DCs with freshly isolated resting NK cells in the presence of Toll-like receptor agonists and proinflammatory cytokines and that the resulting DCs effectively present antigens to induce tumor-specific T-cell responses,which suggests that these cells may be useful for cancer immunotherapy.

Type I and II interferons enhance dendritic cell maturation and migration capacity by regulating CD38 and CD74 that have synergistic effects with TLR agonists

The major limitation for the maturation of dendritic cells(DCs)using Toll-like receptor(TLR)agonists is their decreased ability to migrate into lymph nodes compared with conventional DCs.CD38 can be used as a multifunctional marker to modulate migration,survival and Th1 responses of DCs.CD74 has been shown to negatively regulate DC migration.The goal of this study was to investigate the combinations of TLR agonists and interferons(IFNs)that most effectively regulate CD38 and CD74 expression on DCs.Synergistic TLR agonist stimulation in combination with IFN-a and IFN-c was the best method for regulating CD38 and CD74 expression and inducing the highest secretion of IL-12p70.An in vitro migration assay showed that DCs treated with this combination had significantly enhanced migratory ability,similar to that observed in cells expressing CD38,CD74 and CCR7.The results of this study suggest that an alternative maturation protocol in which two TLR ligands are combined with type I and II IFNs generates potent DCs that have both a high migratory capacity and high IL-12p70 production.