[Regulation of the functional activity of the stem cell precursors of granulo- and monopoiesis by polypeptide factors of the thymus and bone marrow].

Effect of polypeptide thymic and bone marrow factors on functional activity of stem cells was studied with the use of two-layer agar system containing human bone marrow hemopoietic cells. Unlike bone marrow factor, thymic factor appreciably increased the cluster- and colony-forming abilities of cells - precursors of granulomonopoiesis. The results indicate that thymic and bone marrow factors regulate different stages of stem cell differentiation.