Figure 3.

AML cells promote the expansion of Treg through PD-L1. (A,B) HEL cells were transduced to constitutively express full-length human PD-L1, and the mRNA and cell surface protein expression of PD-L1 were determined. Gray filled indicate the vehicle control, and black lines indicate the antibody staining. (C) Treg cells and PD-1⁺ Treg cells were significantly increased when CD4⁺ T cells co-cultured with HEL cells overexpressed PD-L1 for 5 days, and blockade of PD-1 signaling using anti-PD-L1 antibody markedly reduced the generation of Treg cells and PD-1⁺ Treg cells from CD4⁺ T cells. (D,E) HEL cells co-cultured with CFSE-labeled CD4⁺ T cells for 5 days, and subsequently determined the expansion of Treg cells and PD-1⁺ Treg cells. Representative images and statistical data of four independent experiments were shown.