Effect of pregnancy on the activity of hematopoietic stem cells.

Effect of allogenic and syngenic pregnancy on the activity of multifunctional hematopoietic stem cells of bone marrow and spleen was studied. It was observed that bone marrow of mice mated syngenically and allogenically was more capable of restoring hematopoiesis in lethally irradiated recipients as compared to the bone marrow of nonpregnant mice. Increased number of colony forming hematopoietic cells (CFU-S) was recorded also in the spleen of female mice with syngenic pregnancy. When the spleen of pregnant mice mated allogenically, was the source of the multifunctional hematopoietic spleen cells, the animals displayed suppressed capability to restore hematopoiesis which manifested by a decreased number of CFU-S. Splenectomy appeared to have no influence upon the number of CFU-S in the bone marrow of pregnant mice mated allogenically.