OPN-activated DCs polarize T cells toward a Th1- and IFN-γ–secreting phenotype. Naive CD45RA⁺ Th cells (10 × 10³/200 μL) isolated by immunomagnetic negative depletion were polarized by coculture with 12-hour ± OPN-stimulated DCs (5 × 10³/200 μL). On day 5 of coculture, IL-2 (50 U/mL) was added. Cytokine secretion was induced on day 9 by the addition of PMA and ionomycin. Supernatants were obtained after 24 hours and analyzed by cytokine-specific ELISA. Experiments were performed with allogeneic (A) or autologous (B) DCs and Th cells. As positive control for DC-induced Th1 differentiation, DCs were polarized in the allogeneic system by IFN-γ (A); and in the autologous model, with a combination of IL-1β, TNF-α (maturation factor, MF), plus IFN-γ.^20,28  Shown is 1 representative experiment of 2 (A) and 4 (B) independent experiments. Data are expressed as mean pg/mL ± SD of duplicate measurements. Absolute cytokine amounts in the autologous and the allogeneic system cannot be compared because no crossover experiments with matched donor pairs were performed.