Type-I IFNs alter the morphology of DC derived from CD14⁺ precursors.

Mature DC were produced in vitro by culture with GM-CSF, IL-4, and TNF-α, as described in Materials and methods. IFN-β was added to the wells at a final concentration of 1 ng/mL on days 1 and 4 of culture. (A) Photographs of DC were taken on day 10 of culture, as described in Materials and methods: control DC (A, top), IFN-β–cultured DC (A, bottom). Arrows indicate dendritic processes within veils, and the 20-μm reference bar is identical for both panels. (B) On day 10 of culture, cells were harvested and subjected to flow cytometric analysis to evaluate light-scattering properties by forward (x-axis) and side (y-axis) scatter. Nonviable cells were eliminated from analysis using propidium iodide. Results are representative of 5 independent experiments. IFN-β was added at days 1 and 4 of culture at the indicated concentrations.