Files in this Data Supplement:

• Movie 1 (QuickTime Movie, 7,634 KB) - Transfer of MHC to from APC to T cells upon cellular dissociation. Live cell imaging data showing 3 individual T cells forming immunological synapses with APC and capturing MHC:peptide directly from these synapses. Total duration of movie is 18 minutes with an image frequency of 15 seconds. DIC is pseudocolored blue and green is GFP. Movie corresponds to figure 1 in text.
• Movie 2A (QuickTime Movie, 9,065 KB) - 3D rotation of T cells after capturing GFP showing co-localization of MCC:I-E^k:GFP (green) and I-E^k (blue). These cells were not detergent permeabilized and show no anti-GFP staining. Movie corresponds to figure 2A in text.
• Movie 2B (QuickTime Movie, 1,853 KB) - 3D rotation of T cells after capturing GFP showing co-localization of MCC:I-E^k:GFP (green), anti-GFP (red) and anti-Vβ3 (blue). These cells were detergent permeabilized. Movie corresponds to figure 2B in text.
• Movie 2D (QuickTime Movie, 294 KB) - 3D rotation of T cells after capturing MCC:I-E^k:GFP showing colocalization of GFP (green) and anti-Lck (red) and anti-phosphotyrosine (blue). Movie corresponds to figure 2D in text.
• Movie 2E (QuickTime Movie, 510 KB) - 3D rotation of T cells after capturing MCC:I-E^k:GFP showing that the GFP spots (green) on the T cell are surrounded by regions of accumulated F-actin (red). Movie corresponds to figure 2E in text.