Latent membrane protein-1 (LMP1) in EBV-infected cells induces increased expression of IL-6, GM-CSF, and IL-1β through increased glycolysis. These cytokines promote expansion of MDSCs that suppress T cells, NK cells, and other myeloid cells through different mechanisms. T cells are suppressed through the depletion of L-arginine (L-arg) or via the production of reactive oxygen species (ROS). MDSCs inhibit NK cells through expression of transforming growth factor β (TGF-β) and downregulation of NK-cell–activating receptor NKp30. In addition, MDSCs suppress differentiation of myeloid cells through the ROS-dependent pathway. Arg-1, arginase-1; NADPH, nicotinamide adenine dinucleotide phosphate hydrogen.