Fig. 5.

T cell/DC contact morphology and duration. (A) Time-lapse image sequence (times indicated min:sec) illustrating brief contacts between T cells and a DC in the absence of antigen. (Bar = 25 μm.) Top frames are true color (red, T cells; green, DC) projections along the z axis. Frames below are depth-encoded enlarged views of the same images (see also Movie 3). Multiple discrete contacts are indicated (arrows) where the DCs (green) and T cells (red) colocalize in the x-y plane and occupy the same z-position (display the same color) as seen in the pseudocolored image. (B) Contacts between T cells and DCs, rendered in three dimensions (see Movies 4 and 5). Contacts between T cells and DC were dynamic, changing rapidly in size over tens of seconds. Detailed morphometric analysis of several contacts: The average surface area in the contact region was 7.8 μm² (SE = 2.0, n = 32), ranging from more than one-half (>70 μm²) of the T cell's total surface to as little as 1 μm². Contacts took place an average of 16.8 μm (SE = 1.1 μm, n = 26) from the DC center of mass. (C) Histogram of T cell/DC contact durations (89 contacts: median duration = 3.4 min).