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. Author manuscript; available in PMC: 2009 Aug 1.
Published in final edited form as: J Immunol. 2008 Aug 1;181(3):1806–1813. doi: 10.4049/jimmunol.181.3.1806

FIGURE 2. Rapid steady-state homeostasis of FoxP3+ Tregs is associated with increased CTLA4 expression.

FIGURE 2

CFSE-labeled CD4+CD25+ (Tregs) and CD4+CD25− (non-Tregs) from BALB/c (Thy1.2+) mice were transferred into BALB/c (Thy1.1+) congenic hosts (1×106 cells/mouse), harvested after 6 days, stained intracellularly for FoxP3 and additional Treg markers, and analyzed by flow cytometry. (A) CFSE dilution of transferred Thy1.2+ populations, gating on FoxP3+ cells for analysis of Tregs within the CD4+CD25+ transferred population, and gating on FoxP3− cells for analysis of non-Tregs within the CD4+CD25− transferred population. Mean percentage ± SD of divided (CFSElo) Tregs (CD4+FoxP3+Thy1.2+) and non-Tregs (CD4+FoxP3−Thy1.2+) are 53±1% and 6±1%, respectively (n=10 mice per group). (B) Expression of FoxP3, CD25, CTLA4, and GITR on maximally divided (CFSElo) and undivided (CFSEhi) FoxP3+ cells with mean fluorescence intensity (MFI) of each marker indicated. Bar graphs show mean MFI ± SD for each marker expressed by maximally-divided (black) and undivided (white) Tregs from 4 mice per group. Box highlights histogram plots of CTLA4 expression, with the most striking differences in expression between dividing and non-dividing Tregs.