Figure 1. Frequencies of Treg and CD39⁺ Treg in colon adenocarcinoma patients.

Single-cell suspensions were isolated from unaffected colon lamina propria, tumors and PBMC. Treg and conventional T cells were identified by flow cytometry using an isotype control to determine cut-off for Foxp3 expression. The gating strategy is shown in (A), depicting a cell suspension from tumor tissue, and a FACS-plot to aid for gate placement for CD25^hi expression is shown to the far right. Frequencies of Treg among CD4⁺ cells (B), frequencies of CD39⁺ Treg (C), mean fluorescence intensity (MFI) of CD39 expression by CD39⁺ Treg (D), and MFI of Foxp3 expression by CD39⁺ and CD39⁻ Treg (E), was determined by flow cytometry in single cell suspensions from tumors, unaffected colon tissue and peripheral blood. Histograms display fluorescence for selected markers by individual cells from unaffected colon tissue and tumor (D), and from tumor (E). Symbols represent individual values and horizontal lines the median (n = 28). ^*p < 0.05, ^**p < 0.01, ^***p < 0.001, ^****p < 0.0001.