Fig. 6

Trametinib in combination with PD-1 blockade increases the frequency of tumor-infiltrating effector T cells and reduces the proportion of immunosuppressive Treg cells and MDSCs within the tumor microenvironment. A Left panel: Immunohistochemical quantification of Id1 and tumor-infiltrating CD8⁺ T cells (CD8), CD4⁺ T cells (CD4), Treg cells (Foxp3) in LLC tumors harvested from mice shown in Fig. 5B. CD8 T cells/Treg ratio is also shown. Right panel: Representative images of the immunostainings. Scale bar: 200 μm. B Flow cytometric quantification of tumor-infiltrating CD8⁺ T cells (CD45⁺, CD3⁺, CD8⁺, CD44⁺), Treg cells (CD45⁺, CD3⁺, CD4⁺, CD25⁺, Foxp3⁺); total MDSCs (CD45⁺, CD11b⁺, Ly6C⁺), PMN-MDSCs (CD45⁺, CD11b⁺, Ly6C⁺, Ly6G^High), MON-MDSCs (CD45⁺, CD11b⁺, Ly6C⁺, Ly6G^Low) and DCs (CD45⁺, CD11c⁺, MHC-II⁺) from LLC tumors harvested from mice shown in Supplementary Fig. S8A. CD8 T cells/Treg ratio is also shown. Data are expressed as the percentage of total leukocytes (CD45), except for Treg cells, which are expressed as the percentage of total CD4⁺ T cells. Data are expressed as mean ± SD. Comparisons between experimental groups were performed by one-way ANOVA followed by the Tukey post hoc test