[Effect of Iron Overload on Expression of PD-1 on Surface of T Lymphocyte in Mice].

Objective: To investigate the effect of iron overload on the expression of programmed death-1 (PD-1) on the surface of T lymphocyte in mice, in order to analyze the mechanism of iron overload inhibiting T cell function.

Methods: Flow cytometry was used to detect the labile iron pool (LIP), reactive oxygen species (ROS), and the expression of PD-1 in peripheral blood T cells in mice with iron overload.

Results: The mean fluorescence intensity of calcein in T cells of mice in iron overload group was 2 492±311.1, which was significantly lower than 3 136±537.3 in the control group ( P <0.01), suggesting that increased LIP in iron overload group. Compared with the control group, the ratio of CD4/CD8 of peripheral blood T cells was normal or increased in iron overload group. The level of ROS in T cells was 2 452±393.3 in iron overload group, which was significantly increased compared to 1 874±121.8 in the control group ( P <0.001). The expression of PD-1 on the surface of T cells was significantly increased. The percentage of PD-1⁺ cells in CD8⁺T cells was (12.97±6.92)% and (6.18±2.95)% in iron overload group and control group, respectively ( P <0.05), and that in CD8^-T cells was (33.55±15.69)% and (12.51±4.11)% ( P <0.001).

Conclusion: The expression of PD-1 on peripheral blood T cells in mice with iron overload is significantly increased, which may be involved in inhibiting T cell effector function.