CD8⁺ TRLs were isolated by FACS from the spleens of healthy young mice. (A–I) Young male stroke mice were treated intravenously with CD8⁺ TRLs or PBS 2 hours after tMCAO. (A) Flow cytometry to detect adoptively transferred CD45.1⁺CD8⁺ TRLs in CD45.2 congenic mice. (B) Quantification of CD45.1⁺CD8⁺ TRLs in various tissues 1, 3, and 7 days after tMCAO. n = 3–4/group. (C) Quantification of MAP2 staining 3 days after tMCAO in 0, 0.5 × 10⁶, 1 × 10⁶, or 2 × 10⁶ CD8⁺ TRL–treated mice. n = 6–8/group. (D) Neurological deficit score. n = 6–7/group. Sensorimotor dysfunction was assessed by the rotarod (E) and adhesive removal (F) tests up to 14 days after tMCAO. n = 8–12/group. (G–I) Morris water maze 10–14 days after tMCAO. (G) Representative swim paths. (H) Time needed to reach the hidden platform (probe phase). (I) Time spent in the quadrant where the platform had previously been placed was measured 14 days after tMCAO (cued phase). n = 8–12/group. (J–P) Aged (20-month-old) male mice were treated intravenously with 1 × 10⁶ FACS-isolated CD8⁺ TRLs or PBS 24 hours after distal MCAO (dMCAO). n = 10/group. Sensorimotor dysfunction was assessed by the rotarod (J), adhesive removal (K), and foot-fault tests (L) up to 35 days after dMCAO. (M and N) The Morris water maze test at 21–25 days after dMCAO. (O) Nonspatial memory was assessed 35 days after dMCAO using the passive avoidance test. Latency until entry into the dark room from the light room was recorded. (P) Quantification of MAP2 staining 35 days after dMCAO. The areas of contralesional hemisphere are reflected on the ipsilesional hemisphere (dashed white outlines). Yellow dashed line indicates the areas of tissue loss. *P < 0.05; **P < 0.01; ***P < 0.001. Two-tailed Student’s t test (I and N–P), Mann-Whitney test (D), 1-way (C) or 2-way ANOVA (E, F, H, and J–M) and post hoc Bonferroni’s test.