CD1d expression and IFN-γ production by WT peritoneal macrophages treated with LDL or OxLDL. WT peritoneal macrophages were treated with LDL or OxLDL or without additional lipoproteins (control) for 24 hours. (A) Representative histograms of CD1d or H-2K^b expression on the macrophages. I.C. indicates each isotype control for either anti-CD1d or anti-H-2K^b mAb. Cells with PI^low and Mac-1^high phenotypes were gated for analysis. (B) Mean fluorescence intensity (MFI) for CD1d, H-2K^b, I-A^b, or CD40 staining on WT peritoneal macrophages treated with LDL or OxLDL (10 or 50 μg/mL). Each column represents a ratio of MFI of a respective surface molecule to controls at either 24 hours (closed columns) or 48 hours (open columns). Values are mean ± SE of 3 independent experiments. ^*P < .05 vs control (24 hours). ‡P < .01 vs control, LDL10 or LDL50 (24 hours). §P < .05 vs control (48 hours). †P < .01 vs control, LDL10, LDL50, or OxLDL10 (48 hours). (C) Production of IFN-γ in the supernatant of the mixed culture of HMNCs with CD1d^-/- or WT macrophages. HMNCs were cultured for 24 hours with peritoneal macrophages treated with LDL or OxLDL from CD1d^-/- or WT mice. Then IFN-γ levels in the supernatant of the mixed culture were analyzed using ELISA. Values are mean ± SE of 3 independent experiments. †P < .05 vs control, LDL10, or OxLDL10 (WT). P < .01 vs OxLDL50 (CD1d^-/-).