Files in this Data Supplement:

• Supplemental Movie A (QuickTime, 1,543 KB)
• Supplemental Movie B (QuickTime, 2,379 KB)
• Supplemental Movie C (QuickTime, 1,557 KB)
• Supplemental Movie D (QuickTime, 1,955 KB)
  
  - Time-lapse movies of CD40 aggregation on agonist antigen-bearing B cells following synapse formation, as evidenced by CD3 recruitment or calcium flux. Either wild-type fura-loaded D10 T cells (A, B) or CD3ζCFP (C,D) D10 T cells were mixed with CH27-CD40YFP B cells pulsed with either CA agonist (A, C,D) or E8T weak-agonist peptide (B). At 30-second intervals, images were acquired from which a contrast image, a calcium ratio or CD3ζCFP image, a CD40YFP image at mid-z-plane, with or without a reconstruction of the interfacial region are shown. Movie (A) demonstrates capping of CD40 followed by rapid loss of CD40 from the interface region. Movie (B) demonstrates a brief calcium flux generated minutes after weak-agonist encounter but a complete absence of CD40YFP accumulation above basal levels in the interfacial region. Movies (C,D) demonstrate the rapid accumulation of CD40 in the central interface region following encounter in the presence of agonist peptide with accumulation occuring coincident or following the accumulation of CD3.