IVIg modulates cytokine production by DCs.

Immature DCs obtained from culturing monocytes for 5 days in the presence of IL-4 and GM-CSF were incubated in the presence of IVIg (0.15 mM; IVIg) or in the absence of IVIg (Ctl) for an additional 48 hours. In a second set of experiments, DCs were treated with IVIg for 12 hours followed by stimulation with LPS (1 μg/mL) (IVIg-LPS), or they were treated with LPS alone (LPS) for an additional 48 hours to obtain mature DCs. Similarly, immature DCs were treated with HSA for 48 hours (HSA) or were treated 12 hours before the addition of LPS (HSA-LPS). The cell-free culture supernatant was used to measure the secretion of (A) IL-12, (B) IL-10, and (C) TNF-α by Quantikine ELISA. Statistical significance as determined by unpaired Student t test (*P < .05) is indicated.