Immunologic Monitoring of Cellular Responses by Dendritic/Tumor Cell Fusion Vaccines

Figure 2

Immune suppressive responses at the tumor microenvironment. Tumor cells secrete various factors such as VEGF, IL-6, IL-10, TGF-β, Fas-L, IDO, PD-L1, and microvesicles, all of which promote the accumulation of heterogeneous populations of tumor-associated macrophage (TAM), myeloid-derived suppressor cell (MDSC), or tolerogenic DC. These immunosuppressive cells inhibit antitumor immunity by various mechanisms, including elaboration of reactive oxygen species (ROS) and nitrogen oxide (NO). The tumor microenvironment also promote the accumulation of regulatory T cell (Treg) that suppresses CD8+ CTL function through secretion of IL-10 or TGF-β from Tregs and tumor cells.