Efficient and IL-12–dependent CTL generation by mDC1. Naive CFSE-labeled CD8⁺ T cells were cocultured for 7 days with allogeneic DC subsets in the presence of TLR agonists. (A) IFN-γ production of proliferating CD8⁺ T cells was assessed following brief restimulation with phorbol 12-myristate 13-acetate and ionomycin. Shown is the percentage of IFN-γ production among divided CD8⁺ T cells primed by mDC1 (left panel), mDC2 (central panel), or pDC (right panel), which had been stimulated with the indicated TLR agonists in 9 donors in different experiments. Expression of intracellular Granzyme B (B) or Granzyme K (C) in proliferating CD8⁺ T cells primed by the indicated DC subsets stimulated with the indicated TLR agonists. (D) Mean percentage of IFN-γ–producing cells among CD8⁺ T cells that had divided with mDC1 or mDC2 matured with polyI:C and R848. Granzyme-B (E) and Granzyme-K (F) expression in divided naive CD8⁺ T cells primed by mDC1 or mDC2 matured with PolyI:C and R848 in the absence or presence of neutralizing anti–IL-12 antibodies or 1 ng/mL IL-12 as indicated. Shown is the mean of at least 4 donors in at least 3 experiments. ns, not significant. *P < .05; **P < .005; ***P < .0005.