CD8A and infection: There is convincing evidence that both MDSCs and Tregs in aged mice/humans are immunosuppressive, i.e., they suppress the antigen-induced proliferation of T cells, increase the production of IL-10, TGF-β, and ROS, inhibit the maturation and function of DCs, decrease the cytotoxic activity of NK and CD8 T cells and increase the susceptibility to infections and cancer formation [78, 97, 101, 102].