Characterization of mouse hematopoietic stem and progenitor cells.

The unit describes functional assays for the quantification of mouse hematopoietic stem cells and progenitor cells. The competitive repopulating unit (CRU) assay detects transplantable mouse hematopoietic stem cells with the capacity to regenerate all of the blood cell lineages for extended time periods in vivo. The long-term culture-initiating cell (LTC-IC) assay, founded on the bone marrow long-term culture system, measures primitive hematopoietic progenitors based on their capacity to produce myeloid progeny for at least four weeks. Colony-forming cell (CFC) assays, performed in semisolid medium cultures to assess mouse pre-B, megakaryocyte, erythroid, granulocyte-monocyte, and multipotential hematopoietic progenitors are also described. These assays are powerful tools for evaluating human stem cell (HSC) and progenitor content in various hematopoietic tissues, during development as well as in the adult animal, and in cell populations manipulated ex vivo. (c) 2008 by John Wiley & Sons, Inc.