Effect of dasatinib and anti-OX40 treatment on levels and functions of regulatory T cells. (A) Percentages of Treg cells in CD4⁺ T cells in the peripheral blood on day 11 (vehicle + IgG vs dasatinib + IgG: ***P = .0003, vehicle + anti-OX40 vs dasatinib + anti-OX40: **P = .0051, vehicle + IgG vs dasatinib + anti-OX40: *P = .0208). (B) Influence of dasatinib and anti-OX40 on functions of Tregs isolated from 4 different groups (vehicle + IgG vs dasatinib + IgG: *P = .0144, vehicle + IgG vs vehicle + anti-OX40: *P = .0254, dasatinib + IgG vs dasatinib + anti-OX40: **P = .0019, vehicle + anti-OX40 vs dasatinib + anti-OX40: *P = .0488, vehicle + IgG vs dasatinib + anti-OX40: ***P = .0002). (C) Total numbers of Tregs in tumor infiltrating lymphocytes on day 16. (D) Ratios of CD8⁺ effector T cells/Treg cells in tumor-infiltrating lymphocytes on day 16 (vehicle + anti-OX40 vs dasatinib + anti-OX40: **P = .0065, dasatinib + IgG vs dasatinib + anti-OX40: *P = .0228, vehicle + IgG vs dasatinib + anti-OX40: ***P = .0004).