Figure 1.

The frequency of FOXP3⁺, CTLA-4⁺, TIM-3⁺ and PD-1⁺ cells are higher on intratumoral CD4⁺CD25^hi Treg compared with circulating Treg. (A) Flow cytometry gating strategy for analysing CD4⁺ T-cell subsets in PBL and TIL isolated from 10 HNSCC patients. Using paired PBL and TIL CD4⁺ T cells isolated from these patients, gates were set to include CD25 negative (CD25^neg), CD25 low (CD25^lo) and CD25 high (CD25^hi) CD4⁺ T cells. Then, the frequency of FOXP3⁺ cells (B) in CD25^hi CD4⁺ T-cell subset and CTLA-4⁺ (C), TIM-3⁺ (D) and PD-1⁺ (E) cells in CD25^hi FOXP3⁺ Treg was compared between paired PBL and TIL subsets of the same HNSCC patients (n=10).