Fig. 3.

Cross-talk between MDSC and dendritic cells impairs DC function and promotes tumor progression. Tumor-associated DC produce IL-23 which reduces tumor infiltration of CD8⁺ T cells and suppresses NK cell cytotoxicity, thereby promoting tumor growth. IL-23 also induces Th17 cells that secrete IL-17 which supports tumor progression. Increased tumor burden facilitates the accumulation of MDSC which in turn decrease DC maturation, antigen uptake, migration, IL-23, IL-12 and T cell IFNγ production, thereby limiting the activation of CD8-mediated anti-tumor immunity.