1X10^6 C57BL/6 mouse bone marrow cells were surface co-stained with APC Anti-Mouse CD45R (B220) and 0.5 ug FITC Plus Anti-Mouse CD31 (FITC-65058, Clone: 390) or 0.5 ug FITC Rat IgG2a Isotype Control (2A3) (FITC-65209, Clone: 2A3). Cells were not fixed.