HEMATOPOIETIC-CELLS OF FETAL LIVER .1. GROWTH-FACTORS OF DIFFERENT ORIGIN AND ACTIVITY OF GRANULOCYTE-MACROPHAGE CELL PRECURSORS

The liver is the leading hemopoietic organ of 5-22-week embryo and fetus. Hepatic hemopoiesis activity is assessed by concentration, total count and proliferative capacity of granutomonocytic cell precursors (GMCP). Cloning efficacy (GMCP CE) in the liver of 7 fetuses of 16-22 weeks of gestation was evaluated in vitro. Growth factor sources were: healthy subjects (fider), medium conditioned by the umbilical cord, granulocytic-macrophagal colony-stimulating factor (GM CSF), interleukin-3 (IL-3) (Shering Plough), GM CSF+IL-3, serum from patients with chronic glomerulonephritis-Morphological and cytochemical examination of the colonies was performed. There appeared different sensitivity of GMCP of the liver to growth factors. The highest CE (40.8 +/- 5.4 per 2.5 10(5) cells) was found in the usage of GM CSF and GM CSF+IL-3. The colonies reached, 200-500 cells. Low CE occurred after addition to the culture of IL-3 evidencing for minor sensitivity of liver GMCP to this growth factor. Total count of GMCP in the liver was 43.8-146-10(4). Numerous GMCP and predominance of large granulomonocytic colonies in the cultures indicate enhanced activity of GMCP in the livers of 16822 week fetuses. However, GMCP concentration in the above fetuses was 2 times lower than in the marrow of a child with normal hemopoiesis. The discussion covers the adequacy of transplantation to one child with body weight 20-50 kg of the cells obtained from. the liver of one fetus 15-20 weeks old.