CD8A and neoplasm: Likewise, Gattinoni and colleagues demonstrated that effector CD8+ T cells capable of potent in vitro anti-tumor cytotoxicity and IFN-γ production, but not IL-2 production, had limited anti-tumor activity in vivo, whereas T cells that had low in vitro cytotoxicity, but high IL-2 production, mediated superior anti-tumor responses [12].