CD4 cell dynamics. Irradiated 129 mice were reconstituted with B6 CD11c-YFP BM, B6 RFP⁺ CD4 cells, and unlabeled B6 CD8 cells. Ears were imaged ∼28 days after transplantation. (A) Image from a representative video (supplemental Video 1). Mean speeds and displacements for tracked cells are shown in panel B. Each symbol is a unique tracked CD4 cell. (C) Representative tracking from a single video with the starting point of each CD4 cell at the origin. Color denotes time. (D) The mean speed, distance to the YFP surface, and displacement were calculated for each cell in 6 videos (color coded). (E) Average CD4 cell behaviors from 6 videos, represented in a 100-circle plot. “Stable” indicates an instantaneous velocity of less than 5 μm/minute. “In contact” indicates a distance 2 μm or less from the DC surface. “Black space” indicates a distance more than 2 μm from DC surface.