Fig. 2: CD4 help increases the number of effector and memory CD8⁺ T cells by promoting intrahepatic expansion.

a–c Activation marker (CD25/CD69) expression by, and proliferation of, transferred gBT-1 CD8⁺ T cells at early time points post-rAAV^gB-Ag85b treatment. Recipient mice received 1 × 10⁶ CFSE-labelled naïve gBT-1 cells. Representative FACS plots of liver and liver draining LNs (a), proportions of recently activated CD69⁺ (top) and CD25⁺ (bottom) gBT-1 cells at 2-days post-rAAV treatment (b), and CFSE proliferation profiles of gBT-1 T cells isolated from livers and liver draining LNs of rAAV treated recipient mice (c) which had received anti-CD4 mAb or isotype control. d, e Kinetics of total gBT-1 T cell numbers in the liver draining LNs, liver, spleen and 1 ml of blood following rAAV^gB-Ag85b treatment of recipient mice. Comparison of total gBT-1 T cells numbers between CD4-depleted and isotype control treated animals (d), comparison between the different tissues of isotype control treated animals (e). (f–g) Quantification of the level of active cell division (assessed by quantifying the MFI of Ki67) in transferred gBT-1 T cells isolated from CD4 depleted and isotype control treated recipient mice 9-days (f) and 12-days (g) post-rAAV^gB-Ag85b treatment. h, i Representative FACS plot (h) and quantification (i) of the proportion of gBT-1 T cells isolated from the liver and liver draining LNs (dLN) of CD4 depleted and isotype control treated recipient mice 12-days post-rAAV^B-Ag85b treatment. b–i red plots – anti CD4-treated; black plots – isotype control treated. Data are representative of two independent experiments. n = 7 mice (a–e), or n = 5 mice (f–i) per group. Error bars indicate ± SEM. Analysed with a two-tailed unpaired Student’s t test (b) or Mann–Whitney U-test (d, e) and one-way ANOVA with Tukey’s multiple comparisons test (f–i), *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001; Source data are provided as a Source Data file.