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

The liver is the leading hemopoietic organ of 5-22-week embryo and fet us. Hepatic hemopoiesis activity is assessed by concentration, total c ount and proliferative capacity of granutomonocytic cell precursors (G MCP). Cloning efficacy (GMCP CE) in the liver of 7 fetuses of 16-22 we eks of gestation was evaluated in vitro. Growth factor sources were: h ealthy subjects (fider), medium conditioned by the umbilical cord, gra nulocytic-macrophagal colony-stimulating factor (GM CSF), interleukin- 3 (IL-3) (Shering Plough), GM CSF+IL-3, serum from patients with chron ic glomerulonephritis-Morphological and cytochemical examination of th e 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 col onies reached, 200-500 cells. Low CE occurred after addition to the cu lture of IL-3 evidencing for minor sensitivity of liver GMCP to this g rowth factor. Total count of GMCP in the liver was 43.8-146-10(4). Num erous GMCP and predominance of large granulomonocytic colonies in the cultures indicate enhanced activity of GMCP in the livers of 16822 wee k fetuses. However, GMCP concentration in the above fetuses was 2 time s lower than in the marrow of a child with normal hemopoiesis. The dis cussion 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.