Distribution of colony-forming cells in the bone marrow and spleen of irradiated mice

Two hours after transplantation of 2×10⁵ bone marrow cells, 1.7–2.8% and 14–16% of colonyforming units (CFU) were retained respectively in the femoral bone marrow and spleen of the recipients. After 24 h, 1–2% and 21–26% of CFU respectively remained in these organs. If 2.5×10⁶–1.7×10⁷ bone marrow cells were transplanted, the fractionf in the bone marrow and spleen of the recipients (under saturation conditions) was unchanged during the 24-h period. The value for CFU settling in the spleen was 20–22%, whereas for CFU settling in the femoral marrow the value off was 2.4–2.7%. It is postulated that the same number of CFU settles in the whole volume of the bone marrow as in the whole spleen. The total number of CFU settling in the spleen and in the whole volume of the bone marrow averages 40–50%. The fate of the remaining CFU is unknown.Presented by Academician of the Academy of Medical Sciences of the USSR P. D. Gorizontov.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 7, pp. 827–829, July, 1976.