Determination of a CD4CD25FoxP3 T cells subset in tumor-draining lymph nodes of colorectal cancer secreting IL-2 and IFN-γ.

CD4CD25FoxP3 cells are a newly recognized subset of T cells which was first reported in autoimmune diseases. In our previous study, this subset was detected in tumor-draining lymph nodes (TDLNs) of patients with breast cancer. As little is known about their function in TDLNs of cancer patients, in this study, their frequency as well as their ability to produce interleukin (IL)-2, IL-10, or interferon (IFN)-γ were investigated in TDLNs of colorectal cancer (CRC) patients. Mononuclear cells were isolated from lymph nodes of 13 patients with CRC using Ficoll-Hypaque gradient centrifugation. Cells were stimulated in vitro and stained with CD25, CD4, FoxP3, IFN-γ, IL-10, and IL-2 or isotype matched antibodies and subjected to flow cytometry. The frequency of CD4CD25FoxP3CD127 cells was significantly lower than CD4CD25FoxP3CD127 population in TDLNs of CRC patients. The percentage of CD127 cells and also the MFI of FoxP3 expression was significantly lower in CD4CD25FoxP3 in comparison with CD4CD25FoxP3 population. Moreover, CD4CD25FoxP3 cells contained higher percentages of IL-2- and IFN-γ-producing cells than CD4CD25FoxP3 subpopulation. But, no difference was seen between two subsets in terms of IL-10 production. CD4CD25FoxP3 cells in TDLNs of CRC patients had lower suppressive and higher effector properties in comparison with CD4CD25FoxP3 conventional regulatory T cells.