Figure 6. PD-1 and CTLA-4 blockade enhance lymphocyte infiltration and reduce the frequency of Tregs in CT26 tumors.

A) CD45⁺ leukocyte infiltration, and CD8⁺ and CD4⁺ TIL as percent of total CD45⁺ cells 13–15 days after tumor inoculation. B) Representative data showing the percentage of Tregs and expression of GITR among Tregs. C) Percentage of CD45⁺ TILs of Tregs, and the ratios of CD8⁺ or CD4⁺ effector T cells to Tregs in the tumors of treated mice with indicated blocking antibodies. Values are shown for mice analyzed independently and the sum of 3 independent experiments with 6–12 mice per group. Statistical significance was determined by Student’s t-test.