Figure 7.

CD14 is present in intracellular vesicles that are exocytosed in response to LPS. U373–CD14–EGFP cells were incubated for 30 min at 37°C in HAP buffer in the absence (A and B) or presence (C and D) of preformed LPS–sCD14 complexes (40 ng/ml LPS). Trypan blue (200 μg/ml) was added to quench mCD14–EGFP on the cell surface, and the cells were examined by confocal microscopy. Most of the intracellular mCD14–EGFP was localized to a juxtanuclear reticulum (A and C), presumably the Golgi apparatus. In untreated cells, a pool of mCD14–EGFP was also observed in vesicles located throughout the cell but especially prevalent near the basal aspect (B). Most of the vesicular pool of intracellular mCD14–EGFP was no longer visible after stimulation of the cells with preformed LPS–sCD14 complexes (D). Bars, 10 μm.