Septic HSPCs show functional defects in BM transplantation assays. C57BL/6J CD45.2 mice were injected intraperitoneally with LPS from P aeruginosa (0.8 mg/kg) or PBS. BM was harvested at 24 hours from injection, and Lin⁻ or LSK cells, IL-7R⁻ (to exclude contamination from CLPs), were sorted by FACS. Sorted populations were transplanted into irradiated CD45.1 donors, and engraftment was evaluated at each indicated time point by analysis of CD45.2⁺ cells in the peripheral blood. (A) A total of 2 × 10⁵ Lin⁻CD45.2⁺ sorted cells were injected into a lethally irradiated CD45.1⁺ Boy/J recipient together with 3 × 10⁵ Lin⁻CD45.1⁺ competitor cells. Line graph shows engraftment as percentage of CD45.2 cells during time. Values are average of 10 to 12 mice from 3 independent experiments. Bars indicate SE. P value is nonsignificant. (B) A total of 2500 LSK/CD45.2⁺ sorted cells were injected into a lethally irradiated CD45.1 Boy/J recipient together with 10⁵ CD45.1⁺ competitor total BM cells. Line graph shows engraftment as percentage of CD45.2 cells during time. Values are average of 10 to 12 mice from 3 independent experiments. Bars indicate SE. *P < .001. (C) Bar graph shows level of donor engraftment in the PB at 4 weeks of transplantation in mice receiving decreasing doses (2500, 1000, 500) of LSK cells derived from PBS controls or LPS-challenged mice. Values are average of 5 to 8 mice. *P < .001. (D) PB cells were collected and stained with antibodies directed to the myeloid lineage. Bar graph shows percentages of donors Gr1⁺/CD45.2⁺ cells on total GR1⁺ cells (100%) at 2, 4, and 8 weeks from transplantation. Values are average of 8 to 12 mice. Error bars indicate SE. *P < .001.