Spleen, blood, bone marrow (BM) and BAL cells were harvested and single cell suspensions were created by passing the cells through 70 μm pore sized cell strainers (BD Falcon, Durham, NC). Erythrocytes were then lysed using ammonium chloride lysis buffer and washed two times using phosphate-buffered saline (PBS) without calcium, phenol red, or magnesium. Cells were stained with the following antibodies for flow cytometric studies: PE Cy7 anti-CD11b, APC anti-Gr-1, and Pacific Blue anti-Ly6G (BD Pharmingen, Billerica, MA). Additional antibodies used were anti-lineage mixture (Lin; BD Biosciences, San Jose, CA), anti-ckit, anti-Sca-1, anti-CD135, anti-CD150 (eBioscience, San Diego, CA). Sytox Blue (Invitrogen, Carlsbad, CA) was used for cell viability analysis and samples were acquired and analyzed using an LSRII flow cytometer (BD Biosciences) and FACSDiva™ (BD Biosciences)(37 (link), 38 (link)).