Figure 1.

Motility of islet-antigen-specific CD8⁺ and CD4⁺ T lymphocytes in vivo. Irradiated InsHA-mCherry mice adoptively transferred with Clone 4-GFP CD8⁺ and HNT-CFP CD4⁺ T cells were subjected to intra-vital microscopy on day 8. (A) Still image from a representative movie (left panel; scale: 100- and 200-µm Z-projection; red: mCherry, green: GFP, blue: CFP) (see Video S1 in Supplementary Material) and the corresponding T cell tracks (right panel), color-coded as a function of time. Islet is circled. Movie duration: 15 min. (B) Average velocities of pooled CD4⁺ and CD8⁺ T cells in exocrine and endocrine tissues (n = 4 mice/condition; 1–2 movies/mouse, Mann–Whitney). Dots correspond to individual T cells. (C) Directionality indexes (ratio between displacement and total track length) of T cells in exocrine and endocrine tissues (n = 4 mice/condition; 1–2 movies/mouse, Mann–Whitney). Dots correspond to individual T cells. (D) Mean squared displacement (MSD) of T cells as a function of time in islets, best fitted with a confined model of migration for Clone4-GFP cells and with sub-diffusive random walk for HNT-CFP cells. Bars correspond to SEM (n = 4 mice/condition; 1–2 movies/mouse). (E) Still image from a representative movie in the exocrine tissue (left panel; scale: 100- and 200-µm Z-projection; green: GFP, blue: CFP) (see Video S2 in Supplementary Material) and the corresponding T cell tracks (right panel), color-coded as a function of time. Movie duration: 19 min. (F) MSD of T cells as a function of time in the exocrine tissue, best fitted with a Lévy walk model of migration. Between brackets are R²-values of fit for ballistic (directed) motility. Bars correspond to SEM (n = 4 mice/condition; 1–2 movies/mouse).