Fig. 4.

IRF4 is required for reactivation of CD8⁺ T cells. Rag1^−/− mice were reconstituted, infected, and tamoxifen treated as described in Fig. 2. Following 2 wk after tamoxifen treatment, mice were reinfected with LmOVA. After five d, CD8⁺ T cells were analyzed. (A) The experimental scheme. (B) Frequencies of CD44⁺ CD62L⁻ KLRG⁺ CD127⁻ short-lived CD8⁺ effector T cells (C) of granzyme B⁺ BCL2^lo CD8⁺ T cells, (D) Ki-67⁺ CD8⁺ T cells, and (E) BCL2^hi granzyme B⁻ CD8⁺ T cells in spleens of mice with LmOVA reinfection and of mice similarly treated but without reinfection (infected). Mean fluorescence intensity of staining for EOMES (F) and TBX21 (G) in CD8⁺ T cells from spleens of mice. (B–G) Representative results of three independent experiments with four to six mice in reinfected groups and two to four mice in infected groups. Mean ± SEM, paired t test. *P ≤ 0.05, **P ≤ 0.01.