Kinetic expressions of PD-L1 and PD-L2 on the surface of human lymphocytes and monocytes / 中国病理生理杂志

ABSTRACT

AIM: To investigate the expression kinetics of PD-L1 and PD-L2 on the surface of the resting and activated B/T cells as well as monocytes from healthy human peripheral blood.METHODS: Fluorescent antibody staining together with flow cytometry were used to detect the percentages of the resting as well as the activated B cells and T cells that expressed PD-L1 and PD-L2.Meanwhile the percentages of the resting and activated monocytes that expressed PD-L2 were determined.RESULTS: Both resting B cells and T cells did not express PD-L1 on their surface,however PD-L1 expression was significantly up-regulated on the surface of the activated B cells after 6 h stimulation with LPS or pokeweed mitogen(PWM),and the percentages of B cells that expressed PD-L1 reached a plateau at 24 h,which were(46.26?10.71)% with LPS and(43.67?6.14)% with PWM stimulation,respectively.No markedly change of PD-L1 expression on the surface of the activated T cells after stimulation with LPS was observed,but upregulation of PD-L1 expression was observed when stimulation with PWM.The percentages of T cells that expressed PD-L1 reached a plateau at 24 h,which was(25.42?9.23)%.PD-L2 expression was not found on the resting as well as the activated B cells and T cells.In addition,the resting monocytes did not express PD-L2.Combination of INF-? plus LPS markedly induced the PD-L2 expression,and the percentages of monocytes that expressed PD-L2 reached a peak at 48 h,which was(28.70?14.22)%.CONCLUSION: The activated lymphocytes only express PD-L1,reaching a plateau at 24 h.PD-L2 is expressed on the surface of the activated monocytes,reaching a peak at 48 h.