Monomeric mouse IgG1 inhibits acLDL endocytosis through FcγRIII. (A) LPS-primed BMMs (5 × 105/well) derived from FcγRIIB−/− or FcγRIII−/− mice were preincubated with mouse IgG1 or mouse IgG F(ab′)2 at the indicated concentrations at 37°C for 30 minutes, followed by incubation with Alexa Fluor 488–coupled acLDL to allow endocytosis. Cells were then stained with CD11b-biotin and streptavidin–Alexa 568 on ice for 20 minutes to delineate the cell surface before endocytosis examination by confocal microscopy. Endocytosis was measured using confocal microscopy. Representative merged optical sections are presented showing internalized acLDL inside the cell. Scale bars: 5 μm. (B) Quantitative analysis of acLDL endocytosis experiments performed in panel A. Green MFI inside each cell was quantified using LSM510 analysis software that analyzes specific pixels in at least 5 confocal microscope fields (*P < .05, **P < .01, ***P < .001; n = 5; nonparametric Mann-Whitney test).
