GVL is preserved in myeloablated allogeneic BMT recipients treated with R524. BALB/c mice were lethally irradiated (800 cGy) and transplanted with 5 × 106 C57BL/6 TCD-BM cells alone (n = 4) or in addition to 1 × 106 total T cells from WT C57BL/6 and treated twice daily by gavage with vehicle (n = 10) or 40 mg/kg R524 (n = 10) beginning on day 0 (the day of BMT) and continuing daily for 6 weeks. Additionally, recipients were intravenously injected with 2 × 103 A20 luciferase-transduced lymphoma cells at the time as BMT. Recipients were monitored throughout the experimental period for survival (A), weight change (B), and tumor expansion by luciferin intraperitoneal injection and whole body BLI (C). Average survival and weight changes across 2 separate repeat experiments and recipient BLI images from 1 of the 2 replicated experiments are shown. *P < .05; **P < .01; ***P < .001 (compared with vehicle-treated recipients). In a separate experiment in which recipient mice were treated with vehicle or R524 twice daily for 14 days post-BMT, splenocytes were assayed for preserved cytotoxic T lymphocyte (CTL) activity against control EL4 or mismatched P815 tumor target cells ex vivo (D). CTL assay was run in triplicate and normalized to % CD8+ cells in recipient spleens.
