Helper T-cell stimulatory activity of IL-3–IFN-β DCs.

(A) IL-3–IFN-β DCs induce proliferation of naive CD4⁺ T cells. Cord blood CD4⁺ T cells were cultured with allogeneic IL-3–IFN-β DCs (○) or GM-CSF–IL-4 DCs (●) prepared from the same donors. After 5 days, T-cell proliferation was quantified by [³H] thymidine incorporation. Data are shown as mean ± SEM of 6 independent experiments. (B) Production of cytokines in mixed leukocyte cultures. Peripheral blood naive CD4⁺ T cells were cultured with allogeneic IL-3–IFN-β DCs (▨) or GM-CSF–IL-4 DCs (■) at a DC/T ratio of 1:10. After 6 days, culture supernatants were assayed using ELISA for a determination of cytokine levels. Data are shown as mean ± SEM of 6 experiments. *P < .05 compared with DCs generated in GM-CSF and IL-4 (Wilcoxon test).