CD69 and neoplasm: To evaluate the tumor-killing activity of TCRαβ+CD8αα+ IELs, we detected the levels of PD-1, an inhibitory receptor of T cell cytotoxicity, and CD69, an activation marker of T cells, and found they remained similar levels between TCRαβ+CD8αα+ IELs from Kdm6bF/F and Kdm6bF/F-CD4Cre mice (Fig. 8f, g).