In vitro suppressive capacity of Treg cell populations. A, Suppressive capacity of CD25int mTreg and naive Treg (n = 6 donors), and total Treg (n = 5 donors) after in vitro expansion in DMSO control media. B, Suppressive capacity of CD25int mTreg and naive Treg (n = 6 and n = 5 donors, respectively), and total Treg cells (n = 5 donors) after in vitro expansion in the presence of TAC. Percent suppression of CD4+ effector cell proliferation based on division index of PBMCs compared with the proliferation of PBMCs cultured in the absence of suppressor cells. Each data point is the average of 3 replicate wells in the suppression assay of each donor. Mann-Whitney U test used to compare suppression between Treg subpopulations (*P < 0.05). Mean with SEM is represented. C, Ratio of percentage suppression between Treg expanded in DMSO and TAC containing media, using titrated numbers of Treg to Teff cells. (n = 6 donors; Mann-Whitney U test, *P < 0.05). Median with interquartile range is represented.