Direct comparison of T cell motility in the presence and absence of antigen. The time-lapse video montage compares T cells (red) and DCs (green) in the absence of antigen (left) with early cognate interactions between antigen-specific T cells and DCs in the draining lymph node of an Ova-challenged mouse beginning 1 h after adoptive transfer (right). (left) T cells without antigen are move randomly, making brief contacts with labeled DCs; video is played twice. (right) A continuous video shows T cells moving with decreased velocity in a looping pattern and making prolonged but still unstable contacts with antigen-bearing DCs; fewer T cells were adoptively transferred in this case to facilitate tracking of individual cells. Bar, 50 µm. Time indicated as min:s.
