Survival, weight changes, chimerism, and blood-borne BCL₁ cells in recipients with progressive tumor growth treated with infusion of total T cells or memory CD8⁺ T cells. (A) Experimental scheme. Lethally irradiated BALB/c recipient mice were injected with 100 BCL₁ cells 6 hours after irradiation. The next day (day 0), they received 2 × 10⁶ C57BL/6 TCD BM cells (n = 10). On day 16 after BMT, some mice received an intravenous infusion of 0.5 × 10⁶ sorted memory phenotype CD8⁺ T cells (n = 8) or total T cells (n = 8). (B) Survival of recipients with or without infusion. (C) Percentage of starting body weight of host mice given TCD BM with or without infusion as in panel A. (D) Top panels shows 2-color flow cytometric analysis of CD19 versus BCL₁-idiotype markers in the peripheral blood from recipients at day 28 after transplantation of 2 × 10⁶ TCD BM cells with (right panel) or without (left panel) infusion. The boxes enclose BCL₁-idiotype–positive CD19⁺ cells. Bottom panels show representative flow cytometric analysis of the peripheral blood at day 28 stained for donor (H-2K^b+) cells versus TCRβ⁺ cells among gated TCRβ⁺ cells. (E) Representative examples of BLI of lymphoma growth in mice with or without infusion. After total body irradiation, 100 BCL₁-luc⁺–transduced lymphoma cells were injected into BALB/c hosts, followed by injection of 2 × 10⁶ TCD-BM on the next day (day 0). Sixteen days after BMT, experimental mice received an infusion of 0.5 × 10⁶ memory phenotype CD8⁺ T cells, and controls received no infusion. Imaging was performed days 16 and 30 after BMT. Two representative mice from each group of 5 mice are shown. (F) Percentage of donor-type cells among TCRβ⁺ and Mac1/Gr1⁺ cells in the blood and BMT recipients with and without memory-cell infusion.