[Abolishment of allogeneic inhibition of colony formation with the aid of various RNA classes].

The authors analysed the capacity of various temperature fractions of RNA isolated from the spleen of donors of the bone marrow cells (of mice C57BL/6I) and recipients--hybrids (CBA X C57BL/6I) F1 to abolish the depression of colony formation in the nonsyngenous organism. In the administration of bone marrow cells of mice of parental genotype C57BL/6I of the irradiated recipients F1 there is observed a sharp depression of the number of colony forming units in the spleen F1. This depression can be eliminated by preliminary incubation of the bone marrow cells of mice of parental genotype with a 63 degrees fraction of the recipient's RNA. Preliminary inculation of the bone marrow cells of mice of parental genotype with 85 degrees and cytoplasmic fractions of recipient's RNA led to a partial restoration of colony formation only. The 45 degrees and 55 degrees RNA fractions of the recipient's RNA produced no restoring action. None of the temperature RNA fractions of the RNA of donor bone marrow cells were capable of abolishment of the colony formation depression in the nonsyngenous organism. It is supposed that restoration of the colony forming capacity in the nonsyngenous organism was connected with the activity of matrix RNA of the 63 degrees fraction obtained from the recipient's spleen.