title: Formation of macrophage (M) colony-stimulating factor by murine leukemia x fibroblast hybrid cells.
abstract: Clonogenic assays for M, GM, and G precursors of rat or mouse marrow cells were performed in the presence of medium conditioned by the growth of ASL-1 leukemia X LM fibroblast hybrid cells. Both GM- and M-colony-forming units (CFUs) were present in marrow cultures maintained in conditioned medium (CM) from hybrid cells (up to 162 +/- 10 total colonies per 10(5) cells) and from LM cells (65 +/- 5). Conditioned medium from ASL-1 cells did not lead to the formation of CFUs. The hybrid cell-derived CM supported the development of M and GM-CFUs from the marrows of DBA, CAF1, BDF1, C3D2F1, and C57B1/6 mice as well as Lewis, Brown Norway, and Wistar Furth rats. G-CFU were not detected in any of the preparations. Hybrid cell-CM supported the long-term growth and proliferation of macrophage-like cells from mouse spleen, consistent with the presence of M-colony-stimulating factor (CSF). Evidence that M-CSF formed by the hybrid cells and M-CSF formed by L cells shared structural features was provided by antibody neutralization studies. The CFU-promoting activity of hybrid cell-derived M-CSF was neutralized by an antiserum raised in goats against M-CSF purified from L cells. Independently prepared ASL-1 X LM hybrid cells, like the original, led to the formation of GM and M-CFUs. Attempts to detect each of several other previously defined growth factors in medium conditioned by the hybrid cells were unsuccessful. Interleukins 1, 2, and 3; B cell growth factors interferons alpha, beta, and gamma; erythropoietin; and burst promoting factor were not detected.
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells; D002460:Cell Line; D002478:Cells, Cultured; D003115:Colony-Stimulating Factors / Q000096:biosynthesis*; D006822:Hybrid Cells / Q000378:metabolism; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000032:analysis; D007377:Interleukin-3 / Q000032:analysis / Q000096:biosynthesis*; D007942:Leukemia, Experimental / Q000503:physiopathology*; D008264:Macrophages / Q000502:physiology*; D051379:Mice
chemical_list: D003115:Colony-Stimulating Factors; D007376:Interleukin-2; D007377:Interleukin-3