Figure 4. CXCR3 is required for Treg accumulation and activation in tumors.

(A-B) Quantification of intratumoral Treg cell frequency or their PD-1 and CTLA-4 expression from Foxp3^DTR-GFP;Cxcr3⁺/Foxp3^TM2-GFP;Cxcr3^KO female mice harboring Cxcr3⁺ (+PBS, black) or Cxcr3^KO (+DT, red) Treg cells at day 15 (A) or day 28 (B) of MC38 tumor progression (n=7 mice per group, pooled from two independent experiments).

(C) Schematic describing the generation of CXCR3⁺ and Cxcr3ΔTregcells by in vitro differentiation, fluorescent dye-labeling, and co-transfer into MC38 tumor-bearing mice for localization analysis.

(D) Analysis of Treg cells for CXCR3 and T-BET expression prior to adoptive transfer.

(E) Representative flow cytometry plots from dLN and MC38 tumors for transferred Cxcr3⁺ and Cxcr3^KO Treg cells.

(F) Absolute number of Cxcr3⁺ (black) or Cxcr3^KO Treg cells (red) cells recovered. Lines connect Treg cells collected from the same mouse (data pooled from three independent experiments).

Data represents mean ± SEM; *p < 0.05, **p < 0.01 by unpaired (or paired analysis in F) Student’s t tests. Also see Figure S4.