title: Growth of a cultured leukemia subline was promoted by conditioned medium of thymic reticuloepithelial-like cells (B6TE).
abstract: A murine leukemia subline (L17R) was selectively developed in the presence of conditioned medium of a thymic reticuloepithelial-like cell line (B6TE). Cytotoxicity tests and immunofluorescence microscopy showed that L17R cells were negative in the expression of Thy 1.1, Lyt 1.2 and terminal deoxynucleotidyl transferase (TdT), however, 35% positive in Lyt 2.1 phenotype, and 95% positive in the expression of peanut agglutinin (PNA) receptor. B6TE conditioned medium had no activity of interleukin 1 (IL 1), interleukin 2 (IL 2), interleukin 3 (IL 3) and granulocyte/macrophage colony-stimulating factor (GM-CSF). When L17R leukemic cells were plated at a low cell density, their growth was accelerated 40 times by the addition of concentrated B6TE culture supernatant. This growth activity, tentatively designated leukemia-growth-promoting factor (LGPF), was heat sensitive, and its mol. wt was estimated to be approx. 25,000 from the elution pattern of Sephadex G-100 chromatography.
mesh_terms: D000818:Animals; D002450:Cell Communication; D002460:Cell Line; D003470:Culture Media; D004847:Epithelial Cells; D007942:Leukemia, Experimental / Q000473:pathology*; D051379:Mice; D013950:Thymus Gland / Q000166:cytology*
chemical_list: D003470:Culture Media