A soluble activity from adherent marrow cells cooperates with IL 3 in stimulating growth of pluripotential hematopoietic precursors.
Marrow cells from 5-fluorouracil (5-FU)-treated mice formed few or no mixed erythroid colonies when plated in semisolid medium with interleukin 3 (IL 3) and erythropoietin (Ep) alone. When conditioned medium (CM) from plastic-adherent marrow or thymus cells was also included, however, growth of mixed erythroid colonies was strongly stimulated. Both IL 3 and the accessory activity (AA) had to be present at the initiation of the cultures for growth to occur. AA was also produced by a cloned immortalized line (95/1.7) of fibroblastoid marrow cells that lacked macrophage-specific cell surface markers. Colony-stimulating factor-1 (CSF-1) was also released, but not granulocyte colony-stimulating activity. When 95/1.7 CM was analyzed by gel filtration, AA eluted with an apparent size of 35 kd and separated completely from the CSF-1. Biologic assays failed to detect IL 1 or IL 3 activity in 95/1.7 CM. Growth of mixed erythroid colonies from 5-FU-treated marrow is thus stimulated by adherent marrow cell-derived factors that appear distinct not only from the known CSFs including IL 3, but also from IL 1.
Iscove
N N
NN
Ontario Cancer Institute, Toronto, Canada.
Fagg
B
B
Keller
G
G
D000818:Animals; D001853:Bone Marrow / Q000502:physiology*; D001854:Bone Marrow Cells; D002448:Cell Adhesion; D002478:Cells, Cultured; D003470:Culture Media / Q000494:pharmacology; D004357:Drug Synergism; D004920:Erythropoiesis / Q000187:drug effects; D005347:Fibroblasts / Q000378:metabolism / Q000502:physiology; D006133:Growth Substances / Q000502:physiology*; D006410:Hematopoiesis / Q000187:drug effects*; D016298:Hematopoietic Cell Growth Factors; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D007377:Interleukin-3 / Q000494:pharmacology*; D051379:Mice; D008808:Mice, Inbred CBA; D013950:Thymus Gland / Q000166:cytology / Q000502:physiology
D003470:Culture Media; D006133:Growth Substances; D016298:Hematopoietic Cell Growth Factors; D007377:Interleukin-3