FIG. 3.

Twenty-four month old AhR-KO mouse BM cells have decreased long-term competitive repopulation units (CRU) and competitive repopulation ability. (A) Five separate doses of donor CD45.2⁺ BM cells (2, 1, 0.5, 0.1, and 0.05×10⁶) from WT or AhR-KO mice along with 2×10⁵ BM cells from competitive donor mice (CD45.1⁺) were injected into irradiated CD45.1⁺ mice (8 per cell dose per group). Recipient BM cells were analyzed after 20 weeks. (B) Donor BM cells from 24-month old WT and AhR-KO mice were mixed with competitor (CD45.1⁺) cells at a ratio of 1:1 (0.5×10⁶ cells each) and injected into irradiated CD45.1⁺ recipients (6 each for WT and KO). Subsequent serial transplant of BM cells harvested after 6 weeks of transplantation were performed as described in Materials and Methods. BM cells were analyzed for cells of donor (CD45.2⁺) and recipient origin (CD45.1⁺) at each stage of transplantation. Data are presented as mean±S.D. *Values significantly different from control (P<0.05).