The regulation of hemopoiesis in long-term bone marrow cultures. III. The role of burst forming activity.
The addition of burst forming activity (BFA) from mouse spleen conditioned medium (MSCM) to serum-free long-term cultures induced the formation of day 4 BFUE demonstrating that MSCM has an erythropoietin-independent activity on erythroid development. Conditioned medium (CM) from long-term mouse marrow cell cultures was inhibitory to burst formation at concentrations as low as 0.01% when bone marrow cells were used as the external source of BFA, whereas significant levels of inhibition were apparent only at 100-fold greater concentrations of CM in cultures containing MSCM. CM did not inhibit erythropoietin-stimulated erythropoiesis in liquid subcultures of long-term culture cells nor did it stimulate erythroid maturation in the absence of erythropoietin. Adherent cells from the long-term cultures, used as feeder cells, were more active than normal bone marrow cells in enhancing erythroid burst formation.
D000818:Animals; D001854:Bone Marrow Cells; D002448:Cell Adhesion; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D003470:Culture Media; D004920:Erythropoiesis; D004921:Erythropoietin / Q000494:pharmacology; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D013154:Spleen / Q000378:metabolism; D013997:Time Factors
D003470:Culture Media; D004921:Erythropoietin