Figure 3

TCR-induced L-selectin shedding promotes the clonal expansion of effector T cells in virus-infected mice. (A) Thy1.2 CD8⁺ T cells co-expressing the F5 transgenic TCR and either wildtype (F5/B6) or shedding-resistant (F5/L∆P) L-selectin were labelled with CFSE and injected intravenously into naïve Thy1.1 mice. After 24 hours, mice were inoculated intraperitoneally with vaccNP. Non-draining inguinal lymph nodes (ndLN) and draining mediastinal lymph nodes (dLN) were harvested at days 1 and 2 after virus challenge, and donor cells were analyzed for CD69 expression and dilution of CFSE. (B) Bar charts show CD69⁺ F5/B6 and F5/L∆P CD8⁺ T cells in the draining mediastinal lymph nodes at days 1 and 2 post-infection (mean ± SEM, n = 3). (C) Representative histograms show CFSE label in F5/B6 and F5/LΔP CD8⁺ T cells in the draining mediastinal lymph nodes of uninfected mice (control) and infected mice at day 2 after inoculation with vaccNP. Unlabelled cells are shown as light grey histograms. (D) Scatter plots of division indices for F5/B6 and F5/LΔP CD8⁺ T cells at day 2 after infection with vaccNP. Symbols represent individual mice, and lines indicate mean values. (E,F) Bar charts show total numbers of donor F5/B6 and F5/LΔP CD8⁺ T cells in draining mediastinal lymph nodes and non-draining inguinal lymph nodes at days 1 (E) and 2 (F) after infection with vaccNP. Uninfected mice injected with F5 transgenic CD8⁺ T cells are shown for comparison (control). Results are shown as mean ± SEM (n = 3). Statistical significance was assessed using unpaired Student’s 2-tailed t test in panels (D) and two-way ANOVA with Tukey’s post-hoc test in panel (E). *P < 0.05; **P < 0.01.