S1PR5 expression during memory CD8⁺ T cell differentiation. (A) Gene expression of skin, SI-IEL, or lung T_RM cells relative to splenic T_CM and T_EM cells >30 d after HSV (skin T_RM), LCMV (intestine intraSI-IEL T_RM), or WSN.gB (lung T_RM) infection. Gene expression was extracted from the Mackay et al. (2013) dataset (GEO accession no. GSE47045). (B and C) Heatmap representations of gene expression (z-score normalized by row) of mouse and human CD8⁺ T cell subsets. (B) Gene expression of indicated mouse CD8⁺ T cell subsets was analyzed from the Mackay et al. (2013) dataset (GEO accession no. GSE47045) and plotted after log₂ transformation. (C) Gene expression of human CD8⁺ T cell subsets analyzed by qPCR and plotted as a heatmap (z-score normalized by row). Memory T cells were identified as CD8⁺CD45RO⁺ or CD8⁺CD69⁺CD103^+/− in PBMCs or skin, respectively. (D and E) qPCR analysis of gBT-I T cells isolated from the spleen or skin at indicated time points following HSV infection. (D) Gene expression was normalized to naive gBT-I T cells. Graph shows mean ± SD. (E) Gene expression of mouse CD8⁺ T cell subsets analyzed by qPCR and plotted as a heatmap (z-score normalized by row). In D and E, data are from two independent experiments, with n = 5–10 mice per time point. rel., relative; Sk., skin; Spl., spleen; T_N, naive T cell.