Clusters of Ab-patched FL PrPC are largely immobile on the surface of live GT1. (Related to Fig. 5 B, b.) Cells were labeled at 8°C with 8B4 followed by fluorescent secondary Fabs and by tertiary polyvalent clustering Ab. Cells were then warmed gradually to 24°C and analyzed by time-lapse wide field fluorescence microscopy (Axiovert 200M; Carl Zeiss; using an NA 1.3, 100× Plan Neofluar objective) at 400 ms/frame. Time of movie, 24 s, length, 60 frames. Large, intensely staining patches of FL PrPC (with integrated intensity of ∼5 arbitrary units; Fig. 5 C, b) are relatively immobile (mean mobility 0.03 µm/s; Fig. 5 C, a). Notice that many surrounding small 8B4 dots of lower intensity are still very mobile.
