Large-scale expansion of polyclonal CD4⁺CD25^high T cells on CD32⁺ L cells. (A) Proliferation of sorted CD4⁺CD25^high T cells and CD4⁺CD25^- T cells in response to IL-2, anti-CD3/anti-CD28 (precoated and soluble, respectively), or both in the presence or absence of irradiated CD32⁺ L cells. One of 3 independent experiments using cells from 3 different donors. (B) Expansion of sorted CD4⁺CD25^high T cells (n = 9 individual cultures) cultured on irradiated CD32⁺ L cells with anti-CD3 and anti-CD28 Abs plus IL-2. Symbols indicate different donors (n = 5). (C) TCR Vβ-repertoire of primary and 25-day–expanded CD4⁺CD25^high and CD4⁺CD25^- T cells. One of 5 individual cultures with cells from 5 different donors.