Effector cells from the site of inflammation have a general memory phenotype, which is not the cause of their resistance to suppression. (A-C) Paired PBMCs and SFMCs were stained for CD45RA and RO expression by flow cytometry. (A) Dotplots showing the percentage of CD45RA⁻CD45RO⁺ memory cells in PBMCs (left panel) and SFMCs (right panel) CD4⁺ (top panel) and CD8⁺ T cells (bottom panel), 1 representative of n = 4. (B-C) Percentage of CD45RA⁻CD45RO⁺ memory (black bars) and CD45RA⁺CD45RO⁻ naive cells (white bars) in CD4⁺ T cells (B) and CD8⁺ T cells (C) of paired SFMCs and PBMCs of n = 4. (D-E) CD4⁺CD25⁺CD127^low Tregs were sorted by flow cytometry and cocultured with CFSE labeled total, naive, and memory effector T cells at a 1:2 ratio. At day 5, proliferation of CFSE⁺ effector cells (D) and cytokine production in the culture supernatant (E) was analyzed. (D) CFSE profile of CD4⁺CD25⁻ total effector T cells (left panel), CD4⁺CD25⁻CD45RA⁺CD45RO⁻ naive effector T cells (middle panel) and CD4⁺CD25⁻CD45RA⁻CD45RO⁺ memory effector T cells (right panel) cultured in the absence (open histograms) or presence of Tregs (closed histograms). Percentages indicate the percentage suppression of cell proliferation in the presence Tregs relative to effector cells alone, one representative of n = 2. (E) Percentage suppression of IL-5, IL-13, TNFα, and IFNγ production by CD4⁺CD25⁻ total effector T cells (black bars), CD4⁺CD25⁻CD45RA⁺CD45RO⁻ naive effector T cells (gray bars) and CD4⁺CD25⁻CD45RA⁻CD45RO⁺ memory effector T cells (white bars) in the presence of Tregs relative to effector cells alone. Bars represent mean ± SEM of n = 2.