Fig. 6: The expression patterns of E-cadherin by activated T cells are consistent with the characteristics of their internalisation into BEC.

a Airyscan super-resolution confocal micrographs of 4 h co-cultured BEC and 48 h activated CD8⁺ T cells, stained by immunocytochemistry (ICC) for CD8 (yellow) and E-cadherin (magenta). Middle panels show 3D-volume rendered versions of left panel that were acquired using Z-stack microscopy. Right panels show zoomed images of 3D reconstructed Z-stacks from left panel. Bottom section of right panels shows colocalised CD8 and E-cadherin signal (grey). b Representative graphs (contour plot and histogram) of surface E-cadherin staining of CD8⁺ T cells 48 h following α-CD3/CD28 stimulation, as assessed by flow cytometry. c–f Flow cytometry phenotyping of peripheral blood mononuclear cells (PBMCs) isolated from patients undergoing venesection treatment for haemochromatosis (HFE). Cells were phenotyped either when non-activated or 24 h (magenta data points) or 48 h (cyan data points) after α-CD3/CD28 activation. c Percentage of E-cadherin⁺ CD8⁺ T cells comparing non-activated and 48 h-activated CD4⁺ and CD8⁺ T cells. Error bars present median and interquartile range. n = 14 biologically independent patient samples. d Percentage of E-cadherin⁺ CD8⁺ cells without activation and either 24 h or 48 h post-activation. Error bars present median and interquartile range. n = 14 biologically independent patient samples. e Representative flow cytometry contour plots comparing E-cadherin and CD69 expression patterns in CD8⁺ T cells in the absence of activation (black) or following 24 h (red) or 48 h (cyan) activation with α-CD3/CD28. f Percentage of CD8⁺ T cells expressing E-cadherin, CD69, and CD103 assessed via flow cytometry. Error bars present median and interquartile range. n = 14 biologically independent patient samples. All p-values in the figure were generated using two-way Friedman Tests, corrected for multiple comparisons, and are displayed in the figure for each statistical comparison made.