Hematopoietic parameters of CD166^−/−mice. (A) Absolute numbers of LSK48⁻ and LSK48⁻150⁺ cells in the BM and Lin-48⁻ cells in the PB of WT and KO mice (6 mice per group). *P < .05 compared with WT. (B) Percentages of HSPC classes in the marrow of WT and KO mice (6 mice/group). Classes of HSPC were identified as such: LSK (Lin⁻Sca1⁺Kit⁺); MPP (LSKCD34⁺CD135⁺); ST-HSC (LSKCD34⁺CD135⁻); LT-HSC (LSKCD34⁻CD135⁻); 150⁺LT (CD150⁺LSKCD34⁻CD135⁻). *P < .05 compared with WT. (C) Numbers of colony forming unit-granulocyte/macrophage (CFU-GM) in 1 mL of PB and in BM contained in 1 femur from WT and KO mice (n = 5-6 mice per group). *P < .05 compared with WT. (D) Numbers of CFU-GM in 1 mL of PB and in BM contained in 1 femur from WT and KO mice mobilized with G-CSF (2 daily injections of 1 µg/mouse for 4 days). Cells were collected on day 5 (n = 4-5 mice per group). *P < .05 between KO and WT vehicle (Veh) control. #P < .05 compared with Veh in each set. †P < .05 between G-CSF KO and WT. Values in parentheses are fold-increase in CFU-GM numbers between Veh and G-CSF in each tissue. (E) Lethally irradiated F1 mice (n = 13 per group from 3 independent experiments) received 1000 LSK cells from the central region of CD166^−/− mice plus 10e5 CD45.1 competitor cells. *P < .05 compared with WT at corresponding time point. (F) BM chimerism at 4-months PT of LSK cells from 1 of the 3 experiments in (E). *P < .05 compared with WT. (G) Lethally irradiated F1 mice (n = 5 per group) received 1000 LSK cells from the endosteal region of CD166^−/− mice plus 10e5 CD45.1 competitor cells. *P < .05 compared with WT at corresponding time point. (H) Engraftment of 1000 GFP⁺ LSK cells from GFP⁺ WT mice transplanted with 10e5 CD45.1 competitor cells into lethally irradiated WT or KO mice (n = 5 per group). *P < .05 compared with WT at corresponding data points. Chimerism is reported as a percentage of GFP⁺ cells in PB. (I) BM chimerism at 4-months PT of GFP⁺ LSK cells in mice in (H). *P < .05 compared with WT. (J) Survival of lethally irradiated recipients (700 and 400 cGy split dose) over a 30-day period after transplantation with 10e5 low-density BM cells from WT or KO donors. *P < .05 compared with WT group. (K) Numbers of colony-forming units per 10e3 sorted LSK cells from the BM of WT or KO donors retained on WT or KO OB after 16 hours of coculture of both cell types. *P < .05 compared with WT OB-LSK coculture. (L) Fold increase in the number of colony-forming unit produced after 7 days of coculture combinations as shown in the table. Each culture received 1000 LSK cells on day 0. Data are reported as fold-increase relative to the colony-forming unit number obtained from freshly isolated 1000 LSK cells on day 0. *P < .05 compared with WT OB and CD166⁺ LSK coculture (third bar from the left). (M) Expression of different adhesion markers on BM cells from WT and CD166^−/− donors. All antibodies were obtained from Becton-Dickinson or Pharmingen.