[Clonogenic hematopoietic cells (CFU-S) of mouse embryonic liver during short-term in-vivo cultivation].

The stem cell compartment of hemopoietic clonogenic cells (CFU-S) of mouse embryos in a closed system was studied, when the hemopoietic tissue was devoid of supply of the hemopoietic cells and grafted into adult recipients with diverse regulatory influences. The content of hemopoietic clonogenic cells (CFU-S-7, CFU-S-11, and CFU-S-el) was determined in the transplants of the 14-day embryonic liver placed under the renal capsule of preirradiated syngeneic adult recipients. Relatively younger clonogenic cells (CFU-S-11) were practically absent from the transplant in the end of cultivation, while the more advanced stages (CFU-S-7) became more abundant. CFU-S-el were preserved in the transplant for 24 h, and they were absent by the fourth day of cultivation. Disappearance of the clonogenic cells, which are referred to according to some properties as pre-CFU-S (CFU-S-el) from the stem compartment, a decreased content of another category of the clonogenic cells (CFU-S-11), and an increased content of the more advanced cells (CFU-S-7) suggest that in a closed system, maturation of the hemopoietic cells is accompanied by the exit of CFU-S to differentiation and is not compensated by their reproduction from the cells of earlier stages or self-reproduction.