The Long‐term Preservation of Bone Marrow

Murine bone marrow has been preserved for two years and tested for its ability to repopulate the hematopoietic tissues of an irradiated mouse. We have shown that marrow suspended in 12 per cent glycerol and stored at ‐ 196 C retains its repopulating potential, its differentiating capacity, and its ability to undergo selfrenewal. DMSO and temperature of solid CO2 were less efficient. Technics used for the banking of human marrow must rely upon experience gained from studies in other mammals. In vitro assays applicable to both human and animal marrows have suggested that DMSO and ‐ 80 C are satisfactory for marrow preservation. Using more specific assays in the mouse we have shown this combination to be ineffective and suggest that glycerol is a superior cryoprotectant and ‐196 C a more optimal storage temperature for the banking of human marrow.