After infection, activated CD8 T cells differentiate into effector T cells, producing cytotoxic granules including granzymes, perforin, and granulysin as well as cytokines such as interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) to induce programmed death of virus-infected target cells (La Gruta and Turner, 2014). Here, CD8A is linked to infection.