Fig. 5. Translocation of PrP^C to intercellular junctions is induced by cell-cell contacts. Immunofluorescence labeling of PrP^C and PECAM-1 in a pre-confluent culture of RBE4 cells. Nonpermeabilized cells were incubated with anti-PrP^C (SAF32) (A) or anti-PECAM-1 (3A12) antibodies (B) at 2 µg/ml for 16 hours at 4°C, then with Cy2-conjugated anti-mouse antibodies for 45 minutes at 25°C. Images were collected with a confocal fluorescence microscope. Arrows indicate PrP^C (A) or PECAM-1 (B) accumulation at cell-cell contacts. Bars, 20 µm.