Figure 4. The Fc region of 24F4A enhances the inhibition of immune complex-induced IFNα production by human pDCs.

• A–F Isolated human pDCs were treated with increasing concentrations of 24F4A (red circles), 24F4A-ef (black squares), or 10 μg/ml of the isotype control (black triangle) and stimulated with 5 μM of R848 (A and B), 1 μM of CpG-A (C and D), or immune complexes (E and F) for 16 h at 37°C. IFNα concentrations in cultured supernatants were determined using ELISA. Representative plots for each stimulation (A, C and E) and the average IC₅₀ of 24F4A and 24F4A-ef for each stimulation condition (B, D and F) are shown (n = 3). Horizontal bars represent mean IC₅₀, and error bars represent SD of the mean from three independent experiments.
• G Isolated human pDCs were treated with 10 μg/ml of 24F4A (black line), 24F4A-ef (gray shaded histogram), or the isotype control (gray dotted line) for 10 min at 37°C. Flow cytometry was used to evaluate pSYK and pPLCγ2. Shown is a representative plot of two independent experiments.
• H Isolated pDCs treated with 10 μg/ml of anti-CD32a (AT10) and stimulated with CpG-A, R848, or immune complexes. Error bars represent SD of percent inhibition of IFNα from three independent experiments.