Fig. 4: The duration of cognate antigen presentation and the formation of functional memory CD8⁺ T cells are uncoupled.

a WT mice were infected with indicated Lm strains. At specified times, OT-I, gBT, P14 or L9.6 cells were labeled ex vivo with CTV and adoptively transferred to previously infected hosts. Spleen cells were stained for FACS analysis 4 days later. Representative FACS histograms show the dilution of CTV staining in transferred T cells. b Il2ra^mut/mut and WT OT-I cells adoptively transferred to naïve WT mice were subsequently infected the day after with Lm-Ova N4. Antigen presentation was disrupted by injecting anti-MHC-I K^b/Ova_256–264 mAb 48 h post-infection and spleen cells were stained for FACS analysis either 7.5 days later or 6.5 days after re-transfer of sorted memory cells (as in Fig. 2a). Bar graph shows the relative frequency of Il2ra^mut/mut versus WT OT-I cell expansion in 2–5 replicate experiments (n = 10–24 mice). c Same design as in (b), but with Il2ra^mut/mut and WT OT-I cells adoptively transferred to CD11c^DTR/WT recipient mice further injected with diphtheria toxin (DT) 48 h post-infection to deplete CD11c⁺ cells. The bar graph shows the relative frequency of Il2ra^mut/mut versus WT OT-I cell expansion across 2–4 independent replicate experiments (n = 7–16 mice; each symbol represents one mouse).