[Effect of syngeneic lymphocytes, T immunodeficiency and the genotype of bone marrow donors on the differentiation of early and late splenic colonies].

The formation of "early" (5-8 days) and "late" (12-14 days) colonies in spleen of lethally irradiated syngeneic or hybrid recipients after transplantation of bone marrow cells has been studied. The differentiation pattern did not depend on bone marrow cell donor's genotype and the donor-recipient combination. Erythroid to granulocyte colonies ratio (E/G) equals 2. Change of direction of bone marrow colony-forming units (CFU) differentiation has the same pattern at different stages of colony-formation. Under the influence of antigen-stimulated lymphocytes the granulopoiesis (E/G 0.3-0.5) dominanted. The thymectomy of adult animals leads to a predominant formation of erythroid colonies (E/G 3.5-5.1). When T-immunodeficiency is reversed with syngeneic lymphocytes, the differentiation of CFU is normalized at all stages of colony-formation. The process of differentiation of haemopoietic precursors, that form "early" and "late" colonies, is under T-lymphocyte control.