CD8A and neoplasm: Through the production of nitric oxide (NO) and L-arginine (ARG1), MDSCs from tumor-bearing animals suppress the expression of the CD3ζ chain of the T-cell receptor and L-Selectin, inhibit antigen-specific responses from CD8+ T cells, induce to generate regulatory T cells, IL-7 and IL-15, and inhibit the NK cells and the cytotoxic activity of NKT cells [19,20,21,22,23,24,25,26].