[Primary hemopoietic stem cell].

A complex of experimental original laboratory findings is presented to demonstrate a restricted proliferative potential of stem hemopoietic cells. Development of new methodologies to study primitive stem hemopoietic cells, i. e. the cells that are responsible for maintenance of continuous blood formation, allowed for confirming their existence, assessing their content in the hemopoietic tissue, determining the time and site of their embryonic origin, and for showing their limited capacity for regeneration. The obtained evidence is important for the understanding the mechanisms governing hemopoiesis.