Cell cycle status and BrdU incorporation of donor Sca-1⁺ cells in BM and spleen at 1, 3, 6, and 24 hours following transplantation in irradiated or nonirradiated recipients.

Irradiated (A,C) or nonirradiated (B,D) mice received 17-90 × 10⁶ LDBM cells, killed at the indicated time points, and donor Sca-1⁺ cells in BM and spleen analyzed for cell cycle status by PI (A-B) or BrdU incorporation (C-D) by flow cytometry as described in “Materials and methods.” Data are expressed as the mean ± SEM percent of Sca-1⁺ donor cells in G0/G1 phase of cell cycle (A-B) and the mean ± SEM percent of Sca-1⁺ BrdU⁺ donor cells (C-D) at different time points after transplantation. Horizontal lines on panels A and B represent the mean percent of Sca-1⁺ cells in the original graft in G0/G1. The low number of donor Sca-1⁺cells attainable from PB precluded cell cycle analyses of these cells. For each time point, n = 3-9 for panel A, n = 3 for panel B, n = 2-4 for panel C, and n = 3-4 for panel D.