Figure 6.

In vivo suppression by T_reg cells is not associated with stable T_reg cell–T_H cell interactions. CFSE-labeled BDC2.5 CD4⁺CD25⁻ T_H cells were transferred into NOD.Cd28^−/− mice 48 h after injection of CMTMR-labeled BDC2.5 T_reg cells, and the movement of both cell types in explanted pancreatic and inguinal lymph nodes was monitored by time-lapse imaging with TPLSM 24 h after transfer of CD4⁺CD25⁻ T_H cells. (a) Time-lapse images of BDC2.5 CD4⁺CD25⁻ T_H cells (yellowish green) and T_reg cells (red) in pancreatic lymph nodes, with T_reg cell–T_H cell aggregation circled at the beginning of imaging (time is in minutes:seconds). (b) Association time of 102 randomly selected T_reg cell–T_H cell pairs in pancreatic (filled symbols) and inguinal (open symbol) lymph nodes; numbers of pairs with various aggregation time are plotted. Data are representative of one of three independent experiments.