Hemopoietic colony forming units in fresh and cryopreserved peripheral blood cells of canines and man.

Colony forming units (CFUa) were assayed in the peripheral blood and separated mononuclear cells of canines and man. Fresh and cryopreserved samples were studied. By plating 3 x 10-5 canine buffy coat cells or 3 x 10-6 human buffy coat cells between 33 plus or minus 6.6 and 38 plus or minus 1.0 colonies were observed. A high degree of reproducibility was shown for duplicate plates and on repeated testing. Cryopreservation for a one-month period resulted in a minimal recovery of 80 per cent CFUa for canine cells and 96 per cent for human cells. In vivo correlation between peripheral blood CFUa and marrow repopulation was assessed indogs following supralethal whole body irradiation. Prompt repopulation of the marrow was observed and this correlated well with the CFUa assay following infusion of stored buffy coat cells. It was concluded that the peripheral blood of both man and dog have significant numbers of cells with CFUa capabilities that may be potentially useful for marrow grafting purposes.