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. 2013 Dec 23;8(12):e83139. doi: 10.1371/journal.pone.0083139

Figure 6. Enhanced suppressive activity of Treg with selective CD28-blockade.

Figure 6

Treg cells were first primed against alloantigens, washed out and added to CD4+CD25− effector T cells stimulated with allogeneic irradiated mDC at the indicated ratio. Priming was performed with or without CD28 antagonists. Round symbols: no antagonist. Squares: addition of a CD28 antagonist. CD4+CD25− effector T cells proliferation (A, B) and IL-2 synthesis (C, D) after addition of clonal Treg (empty symbols; A, C) or natural Treg (filled symbols; B, D). Addition of Treg to APC in the absence of CD4+CD25− effector T cells resulted in less than 1000 CPM and undetectable IL-2 synthesis (data not shown). Results are mean cpm ± SD or concentration in supernatants measured by CBA of one representative assay out of 3. *p<0.05.