Rg3-CNT reduces PD-1 expression in activated T cells. (A, B) Human PBMCs were cultured, either unstimulated or activated by anti-CD3/CD28 beads, in the presence of control or Rg3-CNT (60 μg/ml) prior to staining with flow cytometry analysis. (C, D) CD69+, CD25+ and CD137+ percentages were determined among the CD4+ and CD8+ T cell populations. Data are presented as mean ± SD. Statistic significant differences were indicated: ns no significance, ** P < 0.01.