Specific M-CSF effect on early HSC commitment correlates with better antibacterial protection than G-CSF during HS/PC transplantation. (a) Mice were transplanted, treated, and infected as described in Fig. 1 a. Survival of mice after transplantation and bacterial infection (arrow) for PBS control (n = 10) or mice treated with rmM-CSF (n = 10), rhM-CSF (n = 11), or rhG-CSF (n = 10) is shown. P < 0.05 (rmM-CSF or rhM-CSF) by a Mantel-Cox test. XR, irradiation. (b) Representative FACS profiles and median of GFP expression in HSCs (KSL CD34⁻ Flt3⁻) and multipotent progenitors (MPP; KSL CD34⁺ Flt3⁺) of PU.1-GFP reporter mice 20 h after control PBS, rhM-CSF, or rhG-CSF injection. **, P < 0.01 by a Mann-Whitney U test. (c and d) Survival of nontransplanted lethally irradiated mice treated with three doses of control PBS (n = 6) or 10 µg rmM-CSF (n = 6) after irradiation (6 h, 12 h, and 24 h) and challenged after 8 (c) or 3 (d) d (arrow) by i.p. injection of 500 CFU of P. aeruginosa. Control mice were treated identically but transplanted with 2,500 HS/PCs (n = 6). ****, P < 0.0001 (rmM-CSF + HS/PC) by a Mantel-Cox test. (e) Survival of mice transplanted with donor HS/PCs from mice treated with three doses (−5 h, −3 h, and −1 h) of 10 µg rmM-CSF (n = 10) or PBS (n = 8) and infected after 3 d (arrow) with 500 CFU of P. aeruginosa. Control recipient mice were treated with three doses of 10 µg rmM-CSF (n = 8) during transplantation. ***, P < 0.001 (rmM-CSF–treated donor HS/PCs) by a Mantel-Cox test. Transplantation (n = 4) and irradiation controls (n = 4) are shown in all survival analyses. All data are representative of two independent experiments.