Figure 4. Circulating memory CD8 T cells need to be reactivated to form TRMs under the influence of VEOs.

(A and B) C57BL/6J mice received 10⁴ CD45.1⁺ naive P14 CD8 T cells and were infected with LCMV. At 70 dpi, SLOs were harvested, and TCMs (live CD8a⁺CD45.1⁺CD62L⁺) and TEMs (live CD8a⁺CD45.1⁺CD62L⁻) were flow sorted and incubated with VEOs for 10 days. In some cases, the cells were exposed to epithelial cells loaded with gp33 peptide (0.2 μg/mL) labeled as reactivated cells. Naive CD8 T cells differentiated in vitro and co-cultured with VEOs were included as a control (effector). Representative flow plots are shown in (A), gated on live congenic marker (CD45.1) T cells, and percentages are enumerated in (B). Data are representative of two repeats with n = 3–5/condition. Bars indicate mean ± SEM. One-way ANOVA with Tukey’s multiple comparison test (B). ****p < 0.0001.