Characterization and enrichment of murine hemopoietic stem cells by fluorescence activated cell sorting.

Several methods for supravital staining of mouse bone marrow cells are described. These methods were employed to sort fractions of bone marrow cells by a light activated cell sorter and to determine cytochemical properties of hemopoietic stem cells. Labelling with fluoresceinated wheat germ lectin confirmed that the stem cells are among the bone marrow cells with the highest surface density of N-acetylneuraminic acid. Staining with tetracycline revealed that the stem cells contain relatively active or relatively many mitochondria. Staining with the bisbenzimide H33342, a supravital DNA stain, indicated that most pluripotent stem cells are in a G0/G1 state of the cell cycle. Using these and other measurements, separation protocols can be devised to concentrate stem cells. Some of these are discussed.