CCR7 and CXCR3 expression demarcates distinct subpopulations of human CD8⁺ T cells with functional effector and memory properties. (A) Sorted CD8⁺ CD45RA⁺ cells were activated with IL-12 plus IFN-α to day 7. Cells were then sorted into separate CCR7^high/CXCR3^low or CXCR3^high/CCR7^low populations. (B) Sorted cells were rested overnight in the absence of IL-2 and subjected to a ⁵¹Cr-redirected lysis assay with THP-1 target cells at the indicated E:T ratios. (C) Sorted cells were labeled with CFSE and left untreated (resting) or activated with 1.5 μg/mL plate-bound anti–human CD3 for 3 days (anti-CD3). On day 3, cells were assessed for proliferation by CFSE dilution. (D) Sorted cells were activated, as described in panel C, and examined at day 3 for expression of perforin and granzyme B by bivariant dot plot analysis. (E) Sorted cells were either left untreated (resting) or activated with 1.5 μg/mL anti-CD3 for 3 days (anti-CD3). On day 3, CCR7^high/CXCR3^low cells (left panel) and CXCR3^high/CCR7^low cells (right panel) were subjected to a redirected lysis assay, as described above. Each of these experiments was performed twice with 2 separate healthy donors with similar results.