Depleting CD25+ Treg cells or adoptive transfer of pre-sensitized CD8+ T cells abrogates long-term islet allograft survival.

<p>B6 mice were treated with MHC I + IL-2/anti-IL-2 and subsequent MHC II + IL-2 prior to transplantation, transplanted with Balb/C islets, and treated with low doses of rapamycin post-transplantation (A + B + Rapa). They were also treated with either depleting anti-CD25 Ab (A + B + Rapa + Anti-CD25) (□, n = 6) or control IgG (A + B + Rapa + Control IgG) (ν, n = 7), or received upon transplantation syngeneic CD8+CD25− (A + B + Rapa + CD8) (○, n = 7) or CD4+CD25− T cells (A + B + Rapa + CD4) (▵, n = 6) that were isolated from B6 mice pre-sensitized <i>i.p</i>. with irradiated Balb/C splenocytes two weeks earlier. Depleting CD25+ Treg cells or adoptive transfer of pre-sensitized CD8+, but not CD4+, T cells reversed long-term islet allograft survival induced by treatments with donor MHC DNA vaccination and IL-2 regimen prior to transplantation plus rapamycin treatment post-transplantation.