Fig. 3.

IFN-α reduces T-cell proliferation but activates innate immune cells and increases the production of IFN-γ. PBLs were activated by anti-CD3/anti-CD28 beads or matured allogeneic mDCs in the presence or absence of increasing levels (1; 10; and 100 ng/ml) rIFN-α and the proliferative responses of T cells, or activation of NK, NKT, and T cells were measured by flow cytometry. The release of IFN-γ was measured with ELISA. a Mean percentage ± SEM proliferating T cells from nine PBL donors at day 5 of culture. b Mean levels of secreted IFN-γ ± SEM from nine PBL donors at day 4 of culture. c Mean percentage ± SEM of proliferating T cells at day 5 induced by nine mDC donors. d Mean levels of secreted IFN-γ ± SEM at day 4 of co-culture induced by five mDC donors. Mean percentage ± SEM NK, NKT, or T cells expressing e the activation marker CD69 or f intracellular IFN-γ after overnight treatment in the presence or absence of increasing levels (1; 10; and 100 ng/ml) rIFN-α from nine PBL donors. g Illustrative drawing of experimental set-up. Statistical differences compared to untreated controls within each treatment group or for each investigated cell type were analyzed by paired one-way ANOVA with Bonferroni’s multiple comparison test and significance is indicated by *(p < 0.05), **(p < 0.01), ***(p < 0.001), or ns (non-significant)