Abstract: | In the system of non-syngeneic transfer of stem hemopoietic cells, the preliminary incubation of the cells of bone marrow or embryonic liver of the C57BL mice with different temperature RNA fractions isolated from the spleen of (CBAXC57BL) F1 was shown to lead to the complete or partial restoration of the colony forming ability of the donor cells. The 63 degrees RNA fraction was shown to have the greatest restorative effect. |