Murine side population cells contain cobblestone area-forming cell activity in mobilized blood.

Primitive hematopoietic stem cells (HSCs) can be purified from murine bone marrow by sorting Hoechst 33342-effluxing side population (SP) cells. The aim of this study was to establish whether SP cells from peripheral blood contain primitive HSCs and whether this is altered in mice following mobilization. SP cells were analyzed and isolated from bone marrow and blood of mice after mobilization; the HSC content of isolated SP cells was determined through surrogate cobblestone area-forming cell (CAFC) assays.