The relation between the proliferative activity and the differentiation pattern of bone marrow cells from Rauscher leukemia virus infected BALB/c mice.

The proliferative activity of bone marrow from Rauscher Leukemia Virus infected mice was studied during the course of the disease. Spleen colony assay and thin-layer agar technique, both presumably reflecting the number of pluripotent hemopoietic stem cells, showed a 2.6 times increase in colony forming units (CFU-S resp. CFU-A) at 12 days after infection. The Bradley method of culturing colonies in agar, which is stated to reflect the number of myeloid precursor cells, resulted in a slower rise in colony forming units (CFU-C) with a maximum of 2.3 times increase at 19 days after infection. These results were compared to the differentiation patterns of the bone marrow at similar intervals after infection. The course of the CFU-C curve parallelled the rise in the number of the myeloblasts in the bone marrow. The pattern of CFU-A and CFU-S curves preceded the rise in number of CFU-C by 7 days. It was found, that RLV infection apart from causing an erythroblastosis in the spleen and a severe anemia is followed by a disappearance of neutrophil granulocytes from the bone marrow. The latter phenomenon is probably the primary cause of the increase of hemopoietic stem cells.