Figure 2

T cell proliferation in the presence of inducible CD4+FoxP3+ T cells. To perform a co-culture suppression assay, responder T cells were labeled with CFSE and cultured in the absence or presence of different ratios of inducible FoxP3+ T cells (20:1 and 2:1) for 3 days in the presence of anti-CD3/CD28 Abs. Gated CD8+ T cells showed CFSE dilution (A, left panel). Responder CD4+ T cells that expressed FoxP3 due to a 3-day activation were also gated and analyzed for CFSE dilution (A, right panel). Cells obtained from a co-culture suppression assay (A, left panel) were also stained for Annexin V in order to determine apoptosis in responder CD8+ T cells (B, left panel) and the B/I-activated CD4+FoxP3+ T cells (B, right panel).