Engineered T cells to counteract the immunosuppressive GBM microenvironment. Major immunosuppressive cell populations and molecules are depicted. For additional details see text. MDSCs: myeloid derived suppressor cells, DCs: dendritic cells, Tregs: regulatory T cells, PD-L1: programmed cell death protein ligand 1,
IDO: indoleamine 2,3 dioxygenase, ARG: arginase, TGFβ: transforming growth factor β. DNR: dominant negative receptor, k/o: knockout.