Figure 2: Tregs interact with LN-resident DCs.

(a) Experimental design to visualize endogenous Tregs together with resident DCs and Tconv cells. CMTMR-labelled Tconv cells from WT C57Bl/6 mice or CFP⁺ Tconv cells from β-actin–CFP mice were adoptively transferred 12 h or 4 days, respectively, prior to imaging, into F1 of Foxp3^EGFP × CD11c^EYFP mice. (b) Interactions among Tconv cells (red), resident DCs (yellow) and Tregs (green) under steady-state conditions. Scale bar, 20 μm, see Supplementary Video 5. (c) Superimposed Treg (green) and Tconv (blue) tracks, z compressed and normalized to DC position at the centre (x, y=0, 0). Data from CFP⁺ Tconv cells are shown; similar results were obtained with CMTMR-labelled Tconv cells. Cells were tracked over 15:21 (min:s). (d) Contact durations between cell pairs: Tconvs interacting with DCs (n=61); Tregs interacting with DCs (n=67). Data from CFP⁺ Tconv cells are shown, and are also representative of results with CMTMR-labelled Tconv cells. Three independent experiments, imaging duration >1 h. (e) Observed contact frequencies with endogenous Tregs by labelled Tconvs (n=47) and by resident DCs (n=36), two experiments.