CD62L-selectin identifies CD8⁺ T cells with superior in vivo antitumor properties. (A) CD62L^high subset possesses superior in vivo antitumor properties. WT mice bearing 10-day-old established subcutaneous B16 tumors were sublethally irradiated and left untreated as control or received adoptive transfer of 1 × 10⁶ of pmel-1 CD62L^high or CD62L^low cells with exogenous rhIL-2 (36 μg per dose) with or without rFPhgp100 vaccination. Results for tumor area are the mean of measurements from 5 mice per group (± SEM). Data shown are representative of 3 independent experiments. (B and C) CD62L^high subset expands vigorously in vivo. (B) Absolute numbers of adoptively transferred CD8⁺ pmel-1cells in the spleen of tumor-bearing, sublethally irradiated WT mice. Mice were treated with FPhgp100, rhIL-2 (36 μg per dose), and 1 × 10⁶ of pmel-1 CD62L^high or CD62L^low cells. Data shown are the mean of 2 mice per group. This experiment was performed twice, with similar results. (C) Percentage of CD8⁺ pmel-1cells in the tumor. Mice were treated with FPhgp100, rhIL-2 (36 μg per dose), and 1 × 10⁶ of pmel-1 CD62L^highLy5.1 or CD62L^lowThy1.1 cells. Data shown are the mean of 2 mice per group. This experiment was performed twice with similar results. (D) CD62L expression is required to maximize the antitumor efficacy of adoptively transferred T cells. WT mice bearing 10-day-old established s.c. B16 tumors were sublethally irradiated and left untreated as control or received adoptive transfer of 1 × 10⁶ one-week-cultured pmel-1 CD62L^+/+ cells or pmel-1 CD62L^–/– cells in conjunction with rFPhgp100 vaccination and exogenous rhIL-2 (36 μg per dose). Tumor area results are the mean of measurements from 5 mice per group (± SEM). Data shown are representative of 3 independent experiments.