Phenotypic and Functional Properties of Tumor-Infiltrating Regulatory T Cells

Figure 1

The role of TI-Treg cells in TME. A schematic illustration of the role of TI-Treg cells in the TME. Activation is shown as blue arrows, and inhibition is shown as red blocked lines. TI-Treg cells inhibit CTLs and CD4 Teff cells by secreting anti-inflammatory cytokines, expressing checkpoint receptors, disturbing metabolism, and killing directly. TI-Treg cells also intercept costimulatory signal on DCs by CTLA-4, preventing activation of Teff cells. Cancer cells attract Treg cells to tumor by secreting chemokines and nurture Treg cells by secreting TGF-β and immunosuppressive metabolites.