Fig. 8: [Ca²⁺]_ex dynamics and integrin αLβ2 activation on the surface of homing T cells in mice.

Splenic T cells from R26-LSL-CEPIAexternal;Itgal-LSL-Clover;Itgb2-LSL-mRuby2;CD4-Cre mice were labeled with Cell-tracer 647 or Cell-tracer 405 for cell tracking in CEPIAexternal imaging and integrin tail FRET imaging respectively, and then injected via tail vein into recipient mice. a Two-photon intravital micrographs of T cells in the psoriasis skin vascular network. Mice were injected with dextran Texas Red and CD31-Alexa Fluor 594 to identify vessels (red). Images are representative of three independent intravital movies. b Intravital micrographs of representative rolling T cells labeled with Cell-tracer 647 (red) in vessels of recipient mice. Square highlights rolling cell. Images are from Supplementary Movie 1. Time is shown in min:s. c Time series showing the dynamic changes of CEPIAexternal ratio and αLβ2 tail FRET in representative T cells during rolling to arrest transition. Pseudocolor signals were shown as an iso-surface (lower left) pattern based on the original fluorescence (upper right) of T cells. Images are from Supplementary Movie 2. Scale bars, 6 µm. d, e Quantification of CEPIAexternal ratio shown in (d) and αLβ2 tail FRET ratio dynamic changes of the cells shown in (e). The αLβ2 tail FRET ratio is normalized to the mean value of cells in a rolling state (R/R₀). Solid lines represent the mean; shaded areas, s.e.m. (n = 12). f Correlation among [Ca²⁺]_ex, αLβ2 activation amplitude and rolling velocity of T cells during rolling to arrest transition. Integrin activation amplitude was defined as the extent of a decrease in the normalized FRET ratio compared with the value of rolling T cells. Solid lines represent the mean; shaded areas, s.e.m. (n = 12). Source data are provided as a Source Data file.