hOSCAR ligation, in combination with TLR ligands, increases the ability of mono-DCs to stimulate MLR and modulates Th1 polarization. (A) Proliferative response of CD45RA+-naive T cells cultured for 5 days with DCs treated with coated MOPC21, anti-CD13, anti-hOSCAR, and TNF was estimated by incorporation of [³H]-thymidine. Data are mean ± SD of quadruplicate samples from 1 representative experiment out of 4. (B) Mono-DCs were stimulated with coated anti-hOSCAR and/or activators (20 ng/mL TNF, 10 ng/mL LPS, 25 μg/mL poly(I:C), 10 μM R-848). After 5 days of culture with CD45RA+ T cells, the lymphocyte proliferation was measured. Data are mean ± SD of quadruplicate samples from 1 representative experiment out of 4 performed with similar results. (C) Polarization of CD45RA+-naive T cells cultured with mono-DCs stimulated with anti-hOSCAR and/or TLR ligands. After 6 hours of PMA/ionomycin stimulation and 4 hours of culture with GolgiPlug, T cells were intracellularly stained with FITC–anti–IFN-γ and PE–anti–IL-4, and analyzed by flow cytometer. Data shown are representative of 6 experiments. Numbers correspond to the percentage of cells in the lower right quadrant. (D) Secretion of IFN-γ by T cells cultured with mono-DCs stimulated with anti-hOSCAR and/or TLR ligands. Supernatant of T cells restimulated by anti-CD3 and anti-CD28 were analyzed by ELISA for the presence of IFN-γ, IL-4, and IL-5. No IL-4 and IL-5 were detected. Data are mean ± SD of triplicate samples from 1 representative experiment out of 3 performed with similar results. ^*P < .01 are given by comparison to values obtained with T cells cultured in the presence of MOPC21-stimulated DCs.