Low concentrations of immobilized but not soluble IgG alter the CD1 profile of dendritic cells. The surface expression of CD1a (A) and CD1d (B) on DCs cultured for 6 days in the presence of IL-4, GM-CSF, and FCS with low doses of immobilized IgG (○) or soluble IgG (•) was measured by flow cytometry. The graphs show the average MFI of CD1a and CD1d cell surface expression (± standard error of the mean) from 9 (immobilized IgG) or 2 (soluble IgG) individual donors.