M-CSF provides antibacterial protection of HS/PC transplant recipients for early infection and single-dose or postinfection cytokine treatment. (a) Mice were transplanted and treated with PBS, M-CSF, or G-CSF as described in Fig. 1 a but infected after 3 d. Survival of mice after transplantation and bacterial infection (arrow) for PBS control (n = 10) or mice treated with three doses of 10 µg rmM-CSF (n = 10) or rhG-CSF (n = 10) is shown. **, P < 0.01 (rmM-CSF) by Mantel-Cox test. XR, irradiation. (b and c) Confocal images with quantification of bacterial colonies (b) or donor cells (c) in spleens 24 h after early infection on day 3 of transplanted mice treated with rmM-CSF or control PBS. ****, P < 0.0001 by a Mann-Whitney U test. Bars, 50 µm. Arrowheads indicate the maximum colony size in the M-CSF–treated group. (d) Mice were transplanted and infected as described in Fig. 1 a but treated with a single dose of control PBS, M-CSF, or G-CSF during transplantation (5 h). Survival of mice after transplantation and bacterial infection (arrow) for PBS control (n = 12) or mice treated with a single dose of 10 µg rmM-CSF (n = 12) or rhG-CSF (n = 12) is shown. **, P < 0.01 by a Mantel-Cox test. (e) Mice were transplanted and infected as described in Fig. 1 a but treated with three doses (1 h, 3 h, and 5 h) of 10 µg rmM-CSF or PBS after infection. Survival of mice after transplantation and bacterial infection (arrow) for PBS control (n = 10) or rmM-CSF (n = 12) is shown. *, P < 0.05 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.