Figure 1: Endogenous Foxp3+ Treg regional behaviour and interaction with Tconvs.
From: Imaging regulatory T cell dynamics and CTLA4-mediated suppression of T cell priming
(a) Tregs in inguinal lymph node from a Foxp3EGFP mouse under steady-state conditions. Green, EGFP+ endogenous Tregs; blue, second-harmonic collagen signal in capsular boundary. Single plane image, scale bar, 100 μm. White square represents area imaged in c. See Supplementary Video 2. (b) T-zone and follicular Tregs (both green), visualized 72 h after adoptive transfer of CFP+CD19+ B cells (blue) and CMTMR-labelled Tconv cells (red). Note: Tregs colocalized with B cells within the dotted outline and at higher density with Tconv cells throughout the T-cell zone. Scale bar, 50 μm. (c) Non-overlapping populations of Tregs in the T-zone and the follicle. Treg movements represented by tracks within (light blue tracks) and outside the B-cell follicle (bright green). Cells tracked over 29:38 (min:s); 35-μm z-stack 50-μm tick marks. (d) Treg velocities in three regions of the lymph node. Each circle represents mean velocity in the T-cell zone (n=174 tracks), in the follicle (n=397 tracks), and within 50 μm of the capsule (n=343 tracks). Data pooled from four experiments. Open circles represent measurements from individual cell tracks; red bars indicate overall mean values and P values are marked in the figures as *P<0.05, **P<0.01, ***P<0.001 and ****P<0.0001 using Mann–Whitney U-test. (e) CMTMR-labelled Tconv cells adoptively transferred 24 h before imaging and tracked with Tregs over 12 min. Still image (top left, scale bar, 30 μm) and corresponding tracks (top right) of Tconv cells (red) and Tregs (green) in the T-zone. Lower panels: magnified views of representative individual Tconv cells and endogenous Tregs (scale bar, 20 μm). Asterisks mark cellular processes. See Supplementary Video 4. (f) Velocities of individual Tregs (n=217 tracks) and Tconvs (n=166 tracks) in the T-zone. Data pooled from three experiments. (g) Tconvs (red) and Tregs (green) in the absence of antigen; right panel pseudocoloured to highlight areas of contact; scale bar, 10 μm.
